What would an asteroid inside of Mercury's orbit be called?

What would an asteroid inside of Mercury's orbit be called?

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The first Vatira asteroid has been discovered. This makes me wonder if there is already a name for the hypothetical class of asteroids that orbit entirely inside of Mercury's orbit. It wouldn't be the first time that an astronomical class is named before being actually observed.

Is there a name to designate the hypothetical subclass of Atira asteroids whose aphelion is closer to the Sun than Mercury's perihelion ?

The name used for such objects is vulcanoids. This term refers to the hypothetical intra-Mercurian planet Vulcan, which was proposed by Urbain Le Verrier (best known for his successful prediction of the existence of Neptune) to account for the anomalous precession of Mercury's orbit that is now explained by general relativity.

Note that the expected number of vulcanoids is low: the Yarkovsky effect should clear out objects smaller than 1 km on ~gigayear timescales (Vokrouhlický et al., 2000), while the YORP effect would be effective at destroying larger objects by spinning them up until they break apart (Collins, 2020). Observational constraints from NASA's STEREO mission suggest the number of objects larger than 1 km may be no more than 76 (Steffl et al., 2013).


Enter your search terms:
asteroid, planetoid, or minor planet, small body orbiting the sun. More than 300,000 asteroids have been identified and cataloged more than a million are believed to exist in the main belt between Mars and Jupiter, with many more in the Kuiper belt beyond Neptune.

Asteroid, also called minor planet or planetoid, any of a host of small bodies, about 1,000 km (600 miles) or less in diameter, that orbit the Sun primarily between the orbits of Mars and Jupiter in a nearly flat ring called the asteroid belt.

Asteroids: the rocky debris of space
Asteroids, though neglected scientifically and publicly for a long time, have been the subject of much interest and debate over the past fifteen years.

Braille (1992 KD) was discovered on May 27, 1992 by astronomers Eleanor Helin and Kenneth Lawrence using the 46 centimeter (18 inch) Shmidt telescope at Palomar Observatory, .

s larger than 200 km in diameter.

s larger than 200 km in diameter.

s are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids.

s might be tiny compared with the other bodies in the solar system, but they're still important. Leftovers from the solar system's earliest days, these rocks preserve the record of planet formation in their makeup. They also make for fun (and sometimes challenging) observing targets.

s are celestial bodies thought to be the remnants of a star's protoplanetary disk, from which larger planets formed. They are larger than meteors while being smaller than planets and are sometimes alternatively known as 'minor planets'.

99942 Apophis will pass within 19,000 miles of the Earth's surface on April 13, 2029, which is closer than some satellites currently orbiting our planet.

s, Meteoroids, and Comets
Start with the name of any of the solar system objects listed in row 1. Find the path that takes you through correct descriptions of that object in each of the subsequent rows. If you've found the correct path, you should finish at the box that restates the object in row 8.

At the dawn of the 19th century, a group of European astronomers known as the Celestial Police was searching for a new planet. A popular mathematical formula suggested that a planet should orbit between Mars and Jupiter.

Rendezvous) Spacecraft. It was taken on June 26, 1997 at a distance of 250,000 miles from the surface. (Courtesy of NASA).

Name and Number* Diameter (km) Mass (kg) Mean Distance from the Sun (km) Orbital Period Discoverer, Date of Discovery
1. Ceres
960 x 932 .

3200 Phaethon, Likely Source of Geminid Meteor Shower, Flies by Earth This Week
Credit: Gianluca Masi/Virtual Telescope Project .

s, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, smaller than planets but larger than meteoroids.
s or minor planet
Minor planet .

Lutetia a rare survivor of Earth's birth
Posted: 11 November 2011 .

Belt Statistics:
Location: 2.2 and 3.2 astronomical units (AU) from the sun.
Average Distance between objects: 600,000 mi/965606.4 km
History of the Name: .

s are actually really useful! .

belt, which is more like a loose grouping than a belt, and lies between 1.8 and 4.5 A.U. (1 A.U. is the average distance between Earth and the sun) from the sun - between the orbits of Mars and Jupiter.

s - Introduction
We have discussed at length the major components of our Solar System. At the center is the Sun and surrounding the Sun are nine planets, many with its own system of moons.

in a given group. The approximate number of known members of each group is listed in the following table (Minor Planet Center).

Gaspra, as photographed by the Galileo space probe (Ref).

. Image credit: Mark A. Garlick, / University of Warwick / University of Cambridge.

will be no closer than 10 times the distance between Earth and the moon. Image credit: NASA/JPL-Caltech .

belt remain there, but some have highly eccentric orbits that take them out of the belt and across the orbital path
of the Earth, as well as the paths of other terrestrial planets.

s are primoridal objects left over from the formation of the Solar System.

known as 16 Psyche. It's our first mission to a world that isn't primarily rocky or icy, but instead metallic. Scientists have said Psyche might be the exposed metal core of an early planet that failed to form.

belt, including citizens of civilised belts such as the Barnard Belt, Sol Main Belt, the Mirthsen-Simoris Spinward Marches, or any of the other innumerable belts in known space.

Belt between Mars & Jupiter.
Orbits are strongly influenced by Jupiter.
Made of rock, metal, or a mix of the two.
Monoliths & Rubble Piles .

(also called planetoid) - A medium-sized rocky object that orbits the Sun. It's smaller than a planet but larger than a meteoroid. Also, any number of small bodies that revolve around the Sun.
Atmosphere - The air all around Earth.

is Ceres, with a diameter of 1,000 km, followed by Pallas (600 km), Vesta (540 km), and Juno (250 km).

s that are basically the same as meteoroids, just larger. Sometimes these objects are also called minor planets.

Click to enlarge NASA concept of
NEAR at 433 Eros .

s are subdivided into several classes. The most distant--those that can cross the orbit of Mars, but that have perihelion distances greater than 1.3 AU's, are dubbed Mars crossers.

ever detected, Vesta, is 530 kilometres wide.

to be discovered wasn't found until 1801 and was named Ceres.

s we've seen up close show cratered surfaces similar to yet different from much of the cratering on comets. Credit: NASA .

. It has a diameter of about about 914 km which is roughly the size of Texas.

? Comet? Alien Solar Sail?
This is not a UFO but stretches the imagination so one can believe. No entities. Check it out. If anything it's a probe.
- .

Jump to Shownotes
Jump to Transcript
Show Notes .

s Milestones
How to Participate in Astronomy Research
Naming of Astronomical Objects
Naming of Exoplanets
Buying Star Names
Naming Stars
Pluto and the Solar System
IAU Member Statistics
Our Moon: the Moon
Meteors & Meteorites: The IAU Definitions of Meteor Terms .

2002 NY40 passed just outside of the Moon's orbit in the morning ours of August 18, 2002. The above movie shows its movement among stars of Hercules from 6:13:16 UT (start of the first frame) to 6:53:31 UT (the end of the last frame).

s database, including UCAS database, 1996
See also[edit] .

s and comets are known to exist in our solar system. Scientists study these space rocks because they are remnants of our solar system's formation 4.6 billion years ago.

s orbit in a belt between Mars and Jupiter astro a prefix that means "star" in the Greek language astronaut a person who travels in space.

s--Small and numerous orbiting rockpiles. A rare possibility of one hitting Earth.
Jupiter--largest, most strongly magnetized, huge radiation belt, polar aurora, colorful active atmosphere
Io and other Jupiter moons--4 big moons: outer ones icy, innermost Io volcanic.

s are made of rock, but some are composed of metal, mostly nickel and iron.

s are similar to comets but do not have a visible coma (fuzzy outline and tail) like comets do.

s are definitely not stars. They are too small even to be classified as planets. Astronomers often refer to them as "minor planets," or sometimes "planetoids." .

s are thought to be fragments of much larger bodies that broke apart early in the life of a Solar System.

belt, located between the orbits or Mars and Jupiter.

Chapter index in this window " " Chapter index in separate window
This material (including images) is copyrighted!. See my copyright notice for fair use practices.

s take them close to the Sun, which also takes them across the paths of the planets. .

- a large rock (which may also include metal) in space, typically in orbit around the Sun more
Be star - a hot star, typically with a disk of material around it more
BCA - beam combining area: see MROI .

s are called meteorites if they fall to the ground.

s orbit the Sun between Mars and Jupiter, and are the source of most meteorites.

A minor planet orbiting the Sun with a diameter greater than one metre and mainly composed of minerals and rock.
Astigmatism .

(Minor Planet): A solid body orbiting the Sun that consists of metal and rock. Most are only a few miles in diameter and are found between the orbits of Mars and Jupiter, too small and far away to be seen easily in a small telescope. A few venture closer to the Sun and cross Earth's orbit.

colors: a novel tool for magnetic field detection? The case of Vesta p. L43
P. Vernazza, R. Brunetto, G. Strazzulla, M. Fulchignoni, P. Rochette, N. Meyer-Vernet and I. Zouganelis
DOI: .

s can be found in a belt between the orbits of Mars and Jupiter. These can be mapped with radio telescopes using radar.
Astrochemistry .

s, some 130,000 of which have an official number. They form the largest group in the category of Small Solar System Bodies.

s: most of them lie in the main belt between the orbits of Mars and Jupiter, while the Trojans move in the same orbit as Jupiter, 60 in front of or behind it.

Belt between Mars and Jupiter.
Atla -- In Norse mythology, a giantess, mother of Heimdall.

Ryugu. Hayabusa 2 entered orbit around Ryugu in July, 2018. It aims to deploy small rovers to the surface, capture a surface sample, and return it to Earth in 2020.

s [A84]
Plano-Concave Lens
A diverging lens with one plane face and once concave face. [DC99] .

is a lump of rock or ice drifting around in space. Some are huge and some are small. When a small one falls into the Earth's atmosphere at high speed, it heats up and glows brightly.

s are small chunks of rock or metal that orbit the Sun in paths that lie largely, but not exclusively, between Mars and Jupiter.

s and dwarf planets.
Astronomical Unit An astronomical unit is the average distance between the centre of the Earth and the centre of the Sun (about 150 million kilometres).

means "star-like." referring to their emission of light.

Distinguishing Orbital Characteristics
Number of Known Bodies
Atens .

s lie.
Astrometry: The precise measurement of objects' positions in the sky.

s II. 1989. R.P. Binzel, T. Gehrels, and M.S. Matthews, Eds., University of Arizona Press, Tucson.

to be discovered by a spacecraft. Its orbit is tilted at an angle of 22.

- (n.)
One of thousands of small planetlike bodies orbiting between Mars and Jupiter having diameters from a fraction of a kilometer to about 1,000 km.
astrobiology - (n.) .

s a very different "absolute magnitude" is used. It tells how bright they would appear to an observer standing on the Sun if the object were one astronomical unit away.
Deep Sky objects .

with orbit inside ours
Galileo and Jupiter .

Orbital Elements Database
The Astronomical Almanac
Astronomy Magazine
Astronomy Now
Astrophysical Data: Planets and Stars by K.R. Lang
Bright Star Catalogue, Fifth Revised Edition by D. Hoffleit and W.H. Warren, Jr.
Burnham's Celestial Handbook by R. Burnham, Jr.

Double Star
A grouping of two stars. This grouping can be apparent, where the stars seem close together, or physical, such as a binary system.

s are also known as the Minor Planets.
Comets .

isotopic signature
SNC meteorites, Sherrgotty India, Nakhla Egypt, Chassigny France .

is just under a kilometer in size and will pass within 14.5 times the distance from the Earth to the Moon. is should be visible in moderate or larger size telescopes near the border of the constellations Lepus and Columba.

whose orbit brings it close to Earth's orbit. The criterion is a perihelion distance

Meet 2020 AV2, the 1st asteroid entirely within the orbit of Venus

Asteroid 2020 AV2 on January 8, 2020. The image is a composite, consisting of 14 60-second exposures, remotely collected with the Elena robotic unit available at the Virtual Telescope Project. The asteroid – 2020 AV2 – is indicated by a white arrow. Image via

Among hundreds of thousands of known asteroids, only 21 ones are known/suspected to have an orbit entirely inside that of the Earth. The just discovered 2020 AV2 is the first one to move entirely inside the orbit of Venus. That fact makes it a very special object. The Virtual Telescope Project contributed to confirm its discovery, and we are proud to present our image (above).

This object is certainly special: it is the first one ever found on an orbit entirely inside that of Venus.

We know quite a number of asteroids. The Minor Planet Center said on May 18, 2019, that it has about 792,000 orbits in its archives. These asteroids are orbiting around the sun at distances spanning a very large range. If we query that database, asking how many of those objects have an orbit entirely inside of the Earth, we get back only 21 asteroids. Clearly, these Inner-Earth Objects, or IEOs – defined by their aphelia Q The orbit of asteroid 2020 AV2, via NASA’s Jet Propulsion Laboratory.

Many years ago, I studied the problem of finding Inner-Earth Objects in depth. It was the topic of my degree thesis, and I published the results on Icarus, suggesting a possible strategy to look for them. I remembered this to make clear how much I’m interested in these very special objects.

On January 4, 2020, the Minor Planet Center reported the discovery by the Palomar Transient Factory of an object labeled ZTF09k5. Its very preliminary orbit indicated it was, indeed, a very interesting finding: it was likely spending all its time around the sun inside the orbit of Venus.

Needless to say, as soon as I learned about it, I wanted to observe this object via the Virtual Telescope Project and contribute to its discovery. Unfortunately, I had to face clouds for several days, making impossible to observe such a very low object at dusk. Last night, at last, the weather was with me, and soon after sunset I managed to carefully prepare the robotic telescope in Ceccano, Italy, a site recognized by the Minor Planet Center with the code 470.

I had more or less 30 minutes to try!

Taking those images was hard, because the object was quite low (25 degrees or less) above the western horizon, at dusk. The sky background was bright, an almost full moon was up in the sky too and the target was lower and lower, minute after minute.

Carefully combining the images, taking the apparent motion of the object into account, I could record ZTF09k5, measure its positions and send them to the Minor Planet Center by email. A few hours later, the Minor Planet Center issued the discovery circular MPEC 2020-A99, with the object now named 2020 AV2 and including my observations (indicated by my observatory code 470 – Ceccano).

Now, I’m pleased to share the image of this rare object with you.

Now we know that 2020 AV2 really has its orbit entirely inside that of Venus, so being the first one of this kind to be ever discovered also, it is the natural object with the smallest known aphelion distance in our solar system (excluding planet Mercury).

With asteroid 2019 AQ3, discovered by the same team, 2020 AV2 has the shortest orbital period known so far in the asteroid population.

The Planevawe 17?-f/6.8 (432/2939 mm) Corrected Dall-Kirkham Astrograph telescope. It is named “Elena” after Elena Persichilli (1940-2016), Gianluca Masi’s mother. This telescope was used to obtain the time at top of 2020 AV2. Image via Virtual Telescope Project.

Bottom line: Report from Gianluca Masi of the Virtual Telescope Project, based in Rome, on his participation in the confirmation of 2020 AV2, the first known asteroid to orbit entirely within the orbit of Venus.

What would an asteroid inside of Mercury's orbit be called? - Astronomy

Could there be another planet that is closer to the Sun than Mercury?

Astronomers in the nineteenth century noticed that Mercury's observed orbital motion differed slightly from what they had calculated. Many thought that these anomalies could be explained by an unseen planet (they called it Vulcan), which would be closer to the Sun than Mercury. The gravitational interactions between Mercury and this hypothetical planet could explain Mercury's observed behavior. A number of astronomers searched for Vulcan, but it was never found. Mercury's orbital motion was eventually explained by Albert Einstein, with general relativity.

There are some smaller objects (asteroids) that go near Mercury. As of July 2015, there are over 200 known asteroids that come within 46 million kilometers of the Sun, meaning that they cross Mercury's orbit, and they can get closer to the Sun than Mercury ever does. (Over the course of Mercury's orbit, its distance from the Sun varies between 46 million km and 70 million km that's 0.31 to 0.47 AU.)

Wait - doesn't mean that Mercury has not "cleared its orbit"? According to the IAU definition, shouldn't Mercury be considered a dwarf planet?

In order for Mercury to be "demoted" from planet to dwarf planet, there would have to be another object of comparable mass that crosses Mercury's orbit (or comes very close to doing so). The asteroids that pass near Mercury are much less massive than Mercury.

But isn't it possible that there is another planet-sized object in there? How can astronomers be sure that "Vulcan" doesn't exist?

It is difficult to observe objects that are close to the Sun, but we have enough observations to say that there cannot be any other bodies in the inner solar system that are large enough to be considered planets.

Asteroids that orbit completely interior to Mercury would be called vulcanoids. As of July 2015, no vulcanoids have ever been found. A study in 2013, using data from NASA's Sun-observing STEREO spacecraft, concluded that there can be no vulcanoids larger than six kilometers in diameter, since none were ever seen by STEREO. The closest known thing to a vulcanoid would be asteroid 2007 EB26, which occasionally gets closer to the Sun than Mercury, but it still spends most of its time outside Mercury's orbit.

New evidence suggests large asteroid strike may have influenced Mercury's spin

( -- Planets orbiting a sun generally, but not always spin on their axis. Some spin east to west, others west to east. Those that don’t spin are said to be tidal locked with their sun always showing it the same face, such as the moon does with planet Earth. In these instances, the planet tends to develop different properties than it would were it spinning. One side is cold, the other hot, for example leading to unique geophysical properties. Also because of the sun’s gravitational pull, more asteroids are likely to hit the far side of the planet, leaving more craters.

It’s partly because of evidence like this that a group of European researchers is proposing that Mercury, the planet closest to the sun in our solar system, was once tidal locked with the sun, but now is not, because, as they assert in their paper published in Nature Geoscience, it was knocked into its current spin by a large asteroid. They even have a likely crater made by the impact to back up their theory.

It’s called Caloris Basin, the largest impact crater on Mercury's surface, and it appears to be just the right size to fit the computer model the team has created. What happened, they suggest, is that long ago, Mercury had an east to west (retrograde) spin, but then over millions of years, slowed till it spun no more. Then, at some later time, the planet was struck by an asteroid large enough to cause it to begin spinning again. But this time, in the opposite direction, though not very fast, causing Mercury’s current 3/2 (three spins on its axis for every two trips around the sun) spin it has today.

The team points out that one side of Mercury clearly has more craters than the other, but perhaps more concretely suggest that the thus far inexplicable hollows inside the Caloris Basin could be the result of ice that was once buried by matter from the asteroid when it hit, then melted as sunlight began to fall on it as a result of the planet spinning again.

And finally, they say, the side that would have been the hot side before being struck by the asteroid would have been flatter than the opposite, more cratered side, do to molten activity. Evidence from Mariner 10 and MESSENGER, suggest that this is the case as well.

It all adds up, the team concludes, to a planet that once spun one way, stopped, then was knocked into spinning the other way.

The planet Mercury rotates three times about its spin axis for every two orbits about the Sun, in a 3/2 spin–orbit resonance. This unique state has been explained by an initial rapid prograde rotation, which was then decelerated by tidal torques to the present resonance. When friction at the core–mantle boundary is accounted for, capture into the 3/2 resonance occurs with a probability of only 26%, whereas the most likely outcome is capture into one of the higher-order resonances7. Here we use a numerical model of Mercury’s rotational evolution to investigate the consequences of an initial retrograde rotation of Mercury. We find that in this case, the planet would be captured into synchronous rotation, with one hemisphere always facing the Sun, with a probability of 68%. Strong lateral variations in the impact cratering rate would have existed, consistent with the observed distribution of large impact basins. Escape from this highly stable resonance can be initiated by the momentum imparted by large, basin-forming impact events, and subsequent capture into the 3/2 resonance is likely. During synchronous rotation, substantial quantities of volatile deposits would have accumulated on the hemisphere facing away from the Sun, potentially explaining the existence of sublimation hollows on Mercury’s surface

An Asteroid has been Found that Orbits the Sun Closer than Venus

Astronomers at Caltech’s Zwicky Transient Facility (ZTF) have discovered an asteroid that orbits inside Venus. Though other asteroids have a portion of their orbit inside Venus’, this is the first one with an orbit that is completely inside Venus’ orbit. The new object is named 2020 AV2.

2020 AV2 is a member of a small class of asteroids called Atiras, objects with orbits inside Earth’s. There are only 21 of them confirmed as of now. They’re also called Interior-Earth Objects (IEOs) because they orbit inside Earth. 2020 AV2 is the first “Vatira” asteroid, where the V stands for Venus.

The asteroid was discovered as part of the ZTF’s Twilight Program. It was first flagged as a candidate on January 4th, 2020, and designated ZTF09k5. After that, an alert was sent out by the Minor Planet Center. After that, other telescopes around the world followed up on the asteroid. That helped confirm the asteroid ‘s orbit and its size.

2020AV2 is about 1 to 3 kilometers in diameter and has an elongated orbit tilted about 15 degrees relative to the plane of our solar system. Its orbit is 151 days long, and its always inside the orbit of Venus. At its perihelion, it comes very close to the orbit of Mercury.

“An encounter with a planet probably flung the asteroid into Venus’s orbit.”

Tom Prince, Professor Physics, Caltech

Tom Prince is a Professor of Physics at Caltech, and a co-investigator of ZTF. In a press release Prince said, “An encounter with a planet probably flung the asteroid into Venus’s orbit. It’s the opposite of what happens when a space mission swings by a planet for a gravity boost. Instead of gaining energy from a planet, it loses it.”

“Getting past the orbit of Venus must have been challenging.”

George Helou, Executive Director, Caltech Astronomy Center

George Helou is the executive director of the IPAC astronomy center at Caltech and a ZTF co-investigator. In a press release, Helou said, “Getting past the orbit of Venus must have been challenging. The only way it will ever get out of its orbit is if it gets flung out via a gravitational encounter with Mercury or Venus, but more likely it will end up crashing on one of those two planets.”

The Samuel Oschin Telescope at the Mount Palomar Observatory. In 2017 it became the host of the Zwicky Transient Facility. Image Credit: Mount Palomar Observatory.

Vatiras are only visible at dusk and dawn, much like Venus, because both are so close to the Sun. The telescope at Zwicky if suited to find objects like this because it scans the sky so quickly. That helped it find 2020 AV2 because the asteroid makes only brief appearances.

As of right now, 2020 AV2 is the only Vatira asteroid that we know of. But nobody really knows how many more there might be. For the team at ZTF, the prospect of finding more is attractive. “We have no idea how many more there are like this or if it’s unique,” said Helou. When the Vera Rubin Observatory (VRO) comes online later this year, it will likely find others, if they’re there.

The Atira asteroids, 2020 AV2, the first Vatira, are not a threat to strike Earth. Their orbits don’t cross Earth’s. But it’s possible that their orbits could change due to gravitational interactions with Venus or Mercury.

Astronomers reveal asteroid 2000 WO107 as a contact binary

In recent days, as asteroid (153201) 2000 WO107 has passed near Earth, radar astronomers at the Goldstone Deep Space Communications Complex in California have been busy observing it. They’ve been bouncing radar signals from its surface and analyzing the signals that are reflected. Astronomers want to observe this asteroid in part because of its relatively large size, and in part because future passes of the asteroid will bring it closer than this year’s pass. This fast-moving asteroid swept closest to Earth on November 29, 2020. Now it’s moving away again, but the astronomers have learned, among other things, that this is no ordinary space rock. Instead, it’s two space rocks that gravitated toward each other until they touched and merged, creating a double asteroid, sometimes called a contact binary asteroid.

It passed at 11.2 times the Earth-moon distance, a very safe distance, on November 29.

Radar observations of asteroids result in images that show us the asteroid’s shape. It’s always lots of fun to see the shapes of these great boulders or mountains hurtling through space. The double aspect of 2000 WO107 was a surprise, however.

Another radar image of contact binary asteroid 2000 WO107 obtained by NASA’s Goldstone Radar in California. Image via NASA/ JPL/ Goldstone.

According to NASA/JPL, the observations of 2000 WO107 might allow scientists to determine the space rock’s composition. The asteroid might be metallic, or it might be an optically dark rock, that is, a rock that is dark in the visible light part of the electromagnetic spectrum.

Before its close pass, astronomers were estimating the space rock’s size at 1,670 feet (510 meters, which is roughly half a kilometer or 1/3 mile) in diameter.

Asteroids come in all sizes. How big is 2000 WO107 in contrast to other asteroids known to pass Earth? In recent years, astronomers have begun catching sight of smaller and smaller asteroids as they sweep past us. Compare the 510 meters of this asteroid to asteroid 2020 SW, which came within 7% of the moon’s distance on September 24, 2020. SW was estimated to be only about 4.5 to 10 meters in diameter (roughly 15 to 30 feet) so at least 50 times smaller. Now compare 2000 WO107’s diameter with the largest object in the asteroid belt between Mars and Jupiter: That object is Ceres, and it’s some 946,000 meters (946 km or 588 miles) in diameter, that is, almost 2,000 times larger than 2000 WO107.

Asteroids travel at different speeds. Large asteroid 2000 WO107 is a fast-moving space rock, traveling through space at the amazing speed of 56,080 miles per hour (90,252 km/h) or 25.1 km per second. By contrast, 2020 SW swept past Earth at “only” 17,336 miles per hour (27,900 km/h), roughly a third of that speed.

Asteroid 2000 WO17 on November 14, 2020, headed for closest approach to Earth on November 29. Image via JPL Small Body Database.

Astronomers at the Lincoln Near-Earth Asteroid Research project (Project LINEAR) in New Mexico discovered 2000 WO107 on November 29, 2000. NASA’s NEOWISE space telescope has also been used to observe it NEOWISE determined that the asteroid’s size is about 510 meters (1,670 feet) in diameter.

Asteroid 2000 WO107 is classified as an Aten type that is, the orbit of this space rock crosses the orbit of the Earth and spends the majority of its time inside Earth’s orbit. The asteroid completes its trip around the sun once every 318 days. Orbit models indicate that, in addition to coming close to Earth on occasion, this asteroid also makes close approaches to Mars, Venus and Mercury.

After the November 29, 2020, visit to Earth, the asteroid will return, passing slightly closer on each subsequent flyby – first in November 2040 – and then in November 2093. An even-closer flyby will happen on December 1, 2140, when the asteroid will pass at about half the Earth-moon distance. Because of its size and occasional relatively close flybys, asteroid 2000 WO107 has been classified as a Potentially Hazardous Asteroid. However, no risk of impact has been detected, as its orbit is well known.

View at EarthSky Community Photos. | Gary Hug in Scranton, Kansas, United States, captured this image of 2000 WO107 in the early morning hours of November 28, 2020, at his Sandlot observatory using a 22-inch telescope. He wrote, “An image of 2000 WO107 taken a little less than a day before its closest approach. It was moving about 1 arcminute (1/60th of a degree) per minute at the time. I added 30 images (causing the star streaks ) moving to the speed and direction of the asteroid.” Fabulous job. Thank you, Guy!

Bottom line: Radar observations of asteroid 2000 WO107 have revealed it as two asteroids stuck together: a contact binary asteroid. The asteroid passed closest on November 29, 2020, at a safe distance of 11.2 times the Earth-moon distance. The asteroid will return, passing slightly closer on each subsequent flyby – first in November 2040 – and then in November 2093.

NASA’s Planetary Defense: “Potentially Hazardous Asteroid” Predicted to Safely Pass by Earth on March 21

This photo shows the view from inside the dome of NASA’s Infrared Telescope Facility during a night of observing. The 3.2-meter (10.5-foot) telescope atop Hawaii’s Mauna Kea will be used to measure the infrared spectrum of asteroid 2001 FO32. Credit: UH/IfA

The interplanetary interloper won’t come closer than 1.25 million miles to Earth, but it will present a valuable scientific opportunity for astronomers.

The largest asteroid predicted to pass by our planet in 2021 will be at its closest on March 21, providing astronomers a rare opportunity to get a good look at a rocky relic that formed at the dawn of our solar system.

Called 2001 FO32, the near-Earth asteroid will make its closest approach at a distance of about 1.25 million miles (2 million kilometers) – or 5 1/4 times the distance from Earth to the Moon. There is no threat of a collision with our planet now or for centuries to come.

“We know the orbital path of 2001 FO32 around the Sun very accurately, since it was discovered 20 years ago and has been tracked ever since,” said Paul Chodas, director of the Center for Near Earth Object Studies (CNEOS), which is managed by NASA ’s Jet Propulsion Laboratory in Southern California. “There is no chance the asteroid will get any closer to Earth than 1.25 million miles.”

Still, that distance is close in astronomical terms, which is why 2001 FO32 has been designated a “potentially hazardous asteroid.” CNEOS computes high-precision orbits for near-Earth objects (NEOs) in support of NASA’s Planetary Defense Coordination Office, relying on telescopes and ground-based radar to help precisely characterize every NEO’s orbit to improve long-term hazard assessments.

During this approach, 2001 FO32 will pass by at about 77,000 mph (124,000 kph) – faster than the speed at which most asteroids encounter Earth. The reason for the asteroid’s unusually speedy close approach is its highly inclined and elongated (or eccentric) orbit around the Sun, an orbit that is tilted 39 degrees to Earth’s orbital plane. This orbit takes the asteroid closer to the Sun than Mercury and twice as far from the Sun as Mars .

This diagram depicts the elongated and inclined orbit of 2001 FO32 as it travels around the Sun (white ellipse). Because of this orbit, when the asteroid makes its close approach to Earth, it will be traveling at an unusually fast speed of 77,000 mph (124,000 kph). Credit: NASA/JPL-Caltech

As 2001 FO32 makes its inner solar system journey, the asteroid picks up speed like a skateboarder rolling down a halfpipe, and then slows after being flung back out into deep space and swinging back toward the Sun. It completes one orbit every 810 days (about 2 1/4 years).

After its brief visit, 2001 FO32 will continue its lonely voyage, not coming this close to Earth again until 2052, when it will pass by at about seven lunar distances, or 1.75 million miles (2.8 million kilometers).

Astronomical Geology

Asteroid 2001 FO32 was discovered in March 2001 by the Lincoln Near-Earth Asteroid Research (LINEAR) program in Socorro, New Mexico, and had been estimated, based on optical measurements, to be roughly 3,000 feet (1 kilometer) wide. In more recent follow-up observations by NEOWISE, 2001 FO32 appears to be faint when observed in infrared wavelengths, which suggests the object is likely less than 1 kilometer in diameter. Analysis by the NEOWISE team shows that it is between 1,300 to 2,230 feet (440 to 680 meters) wide.

Even if it is at the smaller end of the scale, 2001 FO32 will still be the largest asteroid to pass this close to our planet in 2021. The last notably large asteroid close approach was that of 1998 OR2 on April 29, 2020. While 2001 FO32 is somewhat smaller than 1998 OR2, it will be three times nearer to Earth.

The March 21 encounter will provide an opportunity for astronomers to get a more precise understanding of the asteroid’s size and albedo (i.e. how bright, or reflective, its surface is), and a rough idea of its composition.

This will be achieved, in part, with the use of NASA’s Infrared Telescope Facility (IRTF), a 3.2-meter (10.5-foot) telescope atop Hawaii’s Mauna Kea that will observe the asteroid in the days leading up to close approach using its workhorse infrared spectrograph, SpeX. “We’re trying to do geology with a telescope,” said Vishnu Reddy, associate professor at the University of Arizona’s Lunar and Planetary Laboratory in Tucson.

When sunlight hits an asteroid’s surface, minerals in the rock absorb some wavelengths while reflecting others. By studying the spectrum of light reflecting off the surface, astronomers can measure the chemical “fingerprints” of the minerals on the surface of the asteroid. “We’re going to use the IRTF to get the infrared spectrum to see its chemical makeup,” Reddy explained. “Once we know that, we can make comparisons with meteorites on Earth to find out what minerals 2001 FO32 contains.”

For example, should 2001 FO32 be identified as iron-rich, that would mean it’s denser and therefore more massive than a stony asteroid of a similar size observations showing a surface with low albedo (meaning that it’s dark) may indicate the asteroid contains a lot of carbon, suggesting it could be the nucleus of a long-dead comet.

A Closer Look

In addition, radar observations by the Deep Space Network (DSN) may be carried out to get a detailed view of the asteroid. An operation of NASA’s Space Communications and Navigation program (SCaN), the DSN comprises three ground stations – one in California (Goldstone), one in Spain (Madrid), and one in Australia (Canberra). Their dish antennas can be used to bounce radio signals off 2001 FO32 so that other radio antennas can receive them. Such radar observations can offer additional insight into the asteroid’s orbit, provide a better estimate of its dimensions and rotation rate, and help glimpse surface features (like large boulders or craters). They could even reveal any small satellites that may be in tow.

“Observations dating back 20 years revealed that about 15% of near-Earth asteroids comparable in size to 2001 FO32 have a small moon,” said Lance Benner, principal scientist at JPL . “Currently little is known about this object, so the very close encounter provides an outstanding opportunity to learn a great deal about this asteroid.”

Over 95% of near-Earth asteroids the size of 2001 FO32 or larger have been discovered, tracked, and cataloged. None of the large asteroids in the catalog has any chance of impacting Earth over the next century, and it is extremely unlikely that any of the remaining undiscovered asteroids of this size could impact Earth, either. Still, efforts continue to discover all asteroids that could pose an impact hazard. The more information that can be gathered about these objects, the better mission designers can prepare to deflect them if any were to threaten Earth in the future.

Meanwhile, amateur astronomers can gather information of their own about 2001 FO32. “The asteroid will be brightest while it moves through southern skies,” said JPL’s Chodas. “Amateur astronomers in the southern hemisphere and at low northern latitudes should be able to see this asteroid using moderate size telescopes with apertures of at least 8 inches in the nights leading up to closest approach, but they will probably need star charts to find it.”

JPL hosts CNEOS for NASA’s Near-Earth Object Observations Program in NASA’s Planetary Defense Coordination Office. The University of Hawaii manages IRTF under contract with NASA. The SpeX instrument was built at the University of Hawaii.

Zwicky Transient Facility

News &bull February 5th, 2019

Astronomers have discovered an asteroid looping through the inner solar system on an exotic orbit. The unusual object is among the first asteroids ever found whose orbit is confined almost entirely within the orbit of Venus. The asteroid's existence hints at potentially significant numbers of space rocks arcing unseen in uncharted regions nearer to the sun.

A state-of-the-art sky-surveying camera, the Zwicky Transient Facility, or ZTF, detected the asteroid on January 4, 2019. Designated 2019 AQ3, the object has the shortest "year" of any recorded asteroid, with an orbital period of just 165 days. It also appears to be an unusually big asteroidal specimen.

"We have found an extraordinary object whose orbit barely strays beyond Venus' orbit&mdashthat's a big deal," said Quanzhi Ye, a postdoctoral scholar at IPAC, a data and science center for astronomy at Caltech. Ye called 2019 AQ3 a "very rare species," further noting that "there might be many more undiscovered asteroids out there like it."

ZTF is installed on the 48-inch Samuel Oschin Telescope at the Palomar Observatory, located about 122 miles south-east of Los Angeles. It began operations in March 2018 and has already observed more than a billion Milky Way stars, as well as over a thousand of supernovae outside the Milky Way, and other extreme transient cosmic events. ZTF was made possible by funding from the National Science Foundation (NSF). Asteroid research with ZTF is also directly funded by NSF through support of Ye as a Caltech postdoctoral scholar.

A chief science goal of ZTF is rounding up near-Earth asteroids (NEAs), which along with comets that buzz our planet are known as near-Earth objects (NEOs). Scientists at ZTF are especially interested in finding NEAs between about 10 and 100 meters in diameter&mdashnot monstrous in size, but that could still be large enough to severely impact a city should they collide with Earth. Of this potentially Earth-bound set of space rocks, the most concerning are those that come from the direction of the sun, which get lost in the glare and are difficult to measure.

"These small asteroids are only bright enough to be detected during the short period that they are very close to the Earth," said Tom Prince, the Ira S. Bowen Professor of Physics at Caltech with a joint appointment as a senior research scientist at the Jet Propulsion Laboratory, managed by Caltech for NASA, who works on finding NEOs using ZTF. "During this brief window, the asteroids are moving very fast, posing challenges for astronomers to find and track them."

To have any hope of locating such objects, the sky must be scanned very frequently. ZTF surveys the entire northern visible sky every three nights. This excellent coverage comes courtesy of its vast field of view, which in a single exposure, can image approximately two hundred and thirty times the size of the full moon. "The large field-of-view makes ZTF an ideal instrument to find and track rare objects, such as near-Earth asteroids," said Frank Masci, a Staff Scientist at Caltech / IPAC, who oversees and manages the ZTF science data processing system, which is located at IPAC. "ZTF is definitely up to the game."

Leveraging ZTF's capabilities, Ye and Wing-Huen Ip&mdasha professor of astronomy and space science at the Institute of Astronomy and Space Science at the National Central University in Taiwan&mdashproposed the Twilight Survey, which looks for asteroids inbound from the sun. This survey turned up 2019 AQ3 and could yield other interesting asteroids down the road.

A history of asteroidal and cometary successes

Finding NEOs before they find us has long been a major topic at Caltech / IPAC. The center has led the science operations and data processing for NASA&rsquos Wide-field Infrared Survey Explorer (WISE) and NEOWISE missions since their launch in 2009. This asteroid hunter has discovered more than 34,000 new asteroids, including nearly 300 NEAs. ZTF''s predecessor, the Palomar Transient Factory, likewise revealed a bevy of NEOs during its sky survey.

"The sizes of NEOs are best estimated by combining visible and infrared data, which is precisely what we strive to do here at IPAC," said George Helou, Research Professor of Physics at Caltech and the Executive Director of IPAC. "Since its inception, IPAC has been involved in infrared studies of asteroids."

So far, ZTF has logged nearly 60 new near-Earth asteroids. Two of these were spotted in July 2018 mere hours before they gave Earth quite a close shave. Designated 2018 NW and 2018 NX, the duo of bus-sized asteroids whipped past at a distance of about 70,000 miles, or only a third of the way to the moon. Fortunately, the newfound 2019 AQ3 poses no threat the closest it ever comes to Earth is about 22 million miles.

Tracking down 2019 AQ3

The story of how researchers nailed down 2019 AQ3's orbit begins with Ye noting the object in ZTF's images on January 4, 2019. Ye reported the object to the IAU Minor Planet Center, the official worldwide organization charged with gathering data on sun-orbiting objects that are not full planets, such as asteroids and comets. Ye then spent some time mining the ZTF images taken before and after this date to improve projections of the asteroid's orbit.

Two days later, Marco Micheli, a scientist at the European Space Agency, pointed out the target&rsquos uniqueness to the global astronomical community. Multiple other telescopes observed 2019 AQ3 on January 6 and 7, further documenting its uniqueness. A dig through the archives of the Pan-STARRS 1 telescope at the Haleakalā Observatory on the island of Maui, Hawaii, turned up evidence of 2019 AQ3 going back to 2015. With those data in hand, astronomers confidently mapped the object's complete path around the sun.

The orbit, as it turns out, is angled vertically, taking 2019 AQ3 above and below the plane where the planets run their laps around the sun. Over its short year, 2019 AQ3 plunges inside of Mercury, then swings back up just outside of Venus' orbit.

For now, 2019 AQ3 is placed among a peculiar population usually referred to as the Atira or Apohele asteroids, which have orbits interior to Earth's orbit. Among the approximately 800,000 known asteroids, only 20 or so are Atiras. Far greater numbers of these potentially dangerous space rocks are thought to exist, however, the discovery and characterization of which are among the motivations behind the proposed Near-Earth Object Camera (NEOCam) infrared space telescope. Presently funded by NASA for an extended concept study phase, NEOCam is designed to look closer to the sun than previous surveys, which would empower it to pick out hidden asteroids that have long defied detection.

Learning more about known and newfound Atiras, for example their sizes, is an additional goal of ZTF and its fellow instruments. Although the true size of 2019 AQ3 is not yet discernible, limited readings relating to the asteroid's brightness, mass, and density suggest it could be nearly a mile across. If so, 2019 AQ3 would stack up as one of the largest members of the exclusive Atiras group. "In so many ways, 2019 AQ3 really is an oddball asteroid," said Ye.

Finding more space rocks in 2019 AQ3's neck of the woods could lend credence to the long-held idea of vulcanoids&mdashasteroids that swarm inside the orbit of Mercury. The hypothetical population's name derives from a likewise hypothetical planet, Vulcan. Bearing no relation to the fictional home world of Mr. Spock in Star Trek, Vulcan was proposed in the 19th century as the planet closest to the sun whose gravity would explain anomalies measured in Mercury's orbit. Albert Einstein's gravitational framework, the theory of general relativity, explained away these anomalies in 1915, nixing the Vulcan conjecture.

Although ZTF will not have the ability to find vulcanoids, its observing prowess, coupled with that of future telescopes, will enable scientists to at last examine an uncharted region in the inner solar system. ZTF should turn up fresh surprises, as well as give old ideas new chances of being substantiated. "The origin of Atiras is an intriguing and open question," said Ip. "With every additional object, we get closer to formulating and testing models about that origin, and about the history of our Solar System."

For more information about the data in this release visit the IAU Minor Planet Center at:

Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW.

Global Relay of Observatories Watching Transients Happen (GROWTH) is an international collaboration in astronomy with 16 partners from the USA, Sweden, Taiwan, Japan, India, UK, Australia, Germany and Israel. Led by Mansi Kasliwal, an Assistant Professor of Astronomy at Caltech, GROWTH operates a global network of observatories to study cosmic transient events such as supernovae, merging neutron stars, fast moving near-earth asteroids and gamma-ray bursts.

IPAC manages the ZTF Science Data System, handling the calibration and processing of single epoch images, astrometry and photometry, image co-addition and differencing, alert generation, and moving object finding, as well as data archiving and distribution.

Inside Mercury’s orbit

Regular readers may know me as the beloved online blogger for Discover Magazine, but I also sometimes write longer articles for the print version as well.

Last summer, I wrote a piece on the search for small solar system objects that might, theoretically, circle the Sun inside Mercury’s orbit. Called vulcanoids, they are extremely difficult to observe, which is why it’s still not certain if they exist or not (I wrote a brief post about this back in 2008). Two astronomers (and friends of mine), Dan Durda and Alan Stern, are hot on the trail of the purported possible planetesimals I talked to them about their chase and the history of the search for these hot little objects.

Until now, the article was only available in the print magazine or to online subscribers, but now my brilliant prose is open to the public. Seriously, this is a pretty cool topic, and one that most people don’t know about. The region between the Sun and Mercury is closer to the Earth than the main asteroid belt, yet we know much less about it. Read the article and find out why.

Watch the video: Βροχή μετεωριτών στην κεντρική Ρωσία - 15022013 (June 2022).