NASA is Ready to try and fix Lucy’s Unlatched Solar Panel

NASA’s Lucy spacecraft, currently on its way to the outer Solar System to study Jupiter’s Trojan asteroids, has a solar panel problem. Shortly after its launch last October, engineers determined that one of Lucy’s two solar panels failed to open completely. While the spacecraft has enough power to function, the team is concerned about how the unlatched panel might hinder Lucy’s performance going forward. In an attempt to fix the problem, the team will carry out a new procedure next month that is designed to unfurl the solar panel the rest of the way, and latch it firmly in place.

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Astronomers Lined up Under an Asteroid’s Shadow to Measure its Size Precisely

Astronomers will go to great lengths for science. Recently, dozens of astronomers had the misfortune of traveling to one of the most tempting locales in the southwestern US – Las Vegas.  But they weren’t there for the city’s bright lights – they were there to observe a very dim light of a star thousands of light-years away.  And what they specifically wanted to see was the light from that star blink out for a few seconds.  That lack of light provided the exact kind of data they needed to help them determine the size of Eurybates, one of the Trojan asteroids that will be the focal point of NASA’s Lucy mission.

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NASA’s Mission to Visit 8 Asteroids, Lucy, Launches on October 16th

A United Launch Alliance Atlas V rocket with the Lucy spacecraft aboard is seen at Space Launch Complex 41, Thursday, Oct. 14, 2021, at Cape Canaveral Space Force Station in Florida. Credit: NASA/Bill Ingalls.

An early morning launch is planned for the Lucy spacecraft, the first space mission to study Jupiter’s Trojan asteroids. Tomorrow, October 16 at 5:34 a.m. EDT is the first day and time in Lucy’s 21-day launch window, and current weather conditions show a 90% chance of favorable conditions for liftoff from Cape Canaveral Space Force Station in Florida. The launch window remains open for 75 minutes.

Lucy will embark on a 12-year mission to explore the “fossils of planet formation,” Jupiter’s Trojan asteroid swarms. This mission provides the first opportunity to observe these intriguing objects close-up.

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Trojan Mission Lucy Tested its Solar Panels for the First Time. Those Things are Huge

Space missions often have to go where the sun don’t shine. Or at least where it shines very faintly.  That is particularly important if the mission draws its power from the sun.  Luckily, engineers have a way of dealing with that problem – just make really really big solar panels.  That is exactly what they did for Lucy, a mission to visit the Trojan asteroids around Jupiter.  Those sails have now been tested on the ground, and they are magnificent.

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Jupiter has Added a Comet to its Trojan Collection

NASA's Hubble Space Telescope snapped this image of the young comet P/2019 LD2 as it orbits near Jupiter's captured ancient asteroids, which are called Trojans. This icy object is the first comet astronomers have spotted near the Trojan population. CREDITS: NASA, ESA, STScI, B. Bolin (IPAC/Caltech)

Jupiter is notorious for capturing objects that venture too close to the gas giant and its enormous pull of gravity. Asteroids known as Jupiter Trojans are a large group of space rocks that have been snared by the planet, which usually remain in a stable orbit near one of the Jupiter’s Lagrangian points.  

But now, the Hubble Space Telescope has spotted a comet near Jupiter’s Trojan asteroid population. This is the first time a comet has been found in this region, and the team of scientists studying the object  – named P/2019 LD2 (LD2) – think the unexpected comet is only a temporary visitor.

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Jupiter’s Trojan Asteroids Offer Surprises Even Before NASA’s Lucy Mission has a Chance to Visit Them.

Artist’s Rendering of Lucy. Credit: Southwest Research Institute

A new study out this month suggests that Jupiter’s Trojan asteroids may be more peculiar than previously thought. The Trojan asteroids are rocky objects which orbit the Sun just ahead of and just behind the gas giant, in gravitational sweet spots known as Lagrange points. The swarm ahead of Jupiter, known as the L4 (Greek) group, is slightly larger than the L5 (Trojan) swarm behind, but until now, astronomers believed that there was otherwise little differentiation between the two swarms. The paper released this month appears to change that.

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One Mars Trojan asteroid has the same chemical signature as the Earth’s moon

The trojan asteroids of Mars. Credit: Armagh Observatory

Although Mars is much smaller than Earth, it has two moons. Deimos and Phobos were probably once asteroids that were captured by the gravity of Mars. The red planet has also captured nine other small bodies. These asteroids don’t orbit Mars directly, but instead, orbit gravitationally stable points on either side of the planet known as Lagrange points. They are known as trojans, and they move along the Martian orbit about 60° ahead or behind Mars. Most of these trojans seem to be of Martian origin and formed from asteroid impacts with Mars. But one of the trojans seems to have a different origin.

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New Ideas for the Mysterious Tabby’s Star: a Gigantic Planet or a Planet With Rings

Artist's concept of KIC 8462852, which has experienced unusual changes in luminosity over the past few years. Credit: NASA, JPL-Caltech

KIC 8462852 (aka. Tabby’s Star) captured the world’s attention back in September of 2015 when it was found to be experiencing a mysterious drop in brightness. A week ago (on May 18th), it was announced that the star was at it again, which prompted observatories from all around the world to train their telescopes on the star so they could observe the dimming as it happened.

And just like before, this mysterious behavior has fueled speculation as to what could be causing it. Previously, ideas ranged from transiting comets and a consumed planet to alien megastructures. But with the latest studies to be produced on the subject, the light curve of the star has been respectively attributed to the presence of a debris disk and Trojan asteroids in the system and a ring system in the outer Solar System. Continue reading “New Ideas for the Mysterious Tabby’s Star: a Gigantic Planet or a Planet With Rings”

Five New Neptunian Trojans Discovered

Artist's concept of Trojan asteroids, small bodies that dominate our solar system. Credit: NASA

The Solar System is filled with what are known as Trojan Asteroids – objects that share the orbit of a planet or larger moon. Whereas the best-known Trojans orbit with Jupiter (over 6000), there are also well-known Trojans orbiting within Saturn’s systems of moons, around Earth, Mars, Uranus, and even Neptune.

Until recently, Neptune was thought to have 12 Trojans. But thanks to a new study by an international team of astronomers – led by Hsing-Wen Lin of the National Central University in Taiwan – five new Neptune Trojans (NTs) have been identified. In addition, the new discoveries raise some interesting questions about where Neptune’s Trojans may come from.

For the sake of their study – titled “The Pan-STARRS 1 Discoveries of Five New Neptune Trojans“- the team relied on data obtained by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). This wide-field imaging facility – which was founded by the University of Hawaii’s Institute for Astronomy – has spent the last decade searching the Solar System for asteroids, comets, and Centaurs.

PS1 at dawn. The mountain in the distance is Mauna Kea, about 130 kilometers southeast. Credit:
The PS1 telescope at dawn, with the mountain of Mauna Kea visible in the distance. Credit:

The team used data obtained by the PS-1 survey, which ran from 2010 to 2014 and utilized the first Pan-STARR telescope on Mount Haleakala, Hawaii. From this, they observed seven Trojan asteroids around Neptune, five of which were previously undiscovered. Four of the TNs were observed orbiting within Neptune’s L4 point, and one within its L5 point.

The newly detected objects have sizes ranging from 100 to 200 kilometers in diameter, and in the case of the L4 Trojans, the team concluded from the stability of their orbits that they were likely primordial in origin. Meanwhile, the lone L5 Trojan was more unstable than the other four, which led them to hypothesize that it was a recent addition.

As Professor Lin explained to Universe Today via email:

“The 2 of the 4 currently known L5 Neptune Trojans, included the one L5 we found in this work, are dynamically unstable and should be temporary captured into Trojan cloud. On the other hand, the known L4 Neptune Trojans are all stable. Does that mean the L5 has higher faction of temporary captured Trojans? It could be, but we need more evidence.”

In addition, the results of their simulation survey showed that the newly-discovered NT’s had unexpected orbital inclinations. In previous surveys, NTs typically had high inclinations of over 20 degrees. However, in the PS1 survey, only one of the newly discovered NTs did, whereas the others had average inclinations of about 10 degrees.

Animation showing the path of six of Neptune's L4 trojans in a rotating frame with a period equal to Neptune's orbital period.. Credit: Tony Dunn/Wikipedia Commons
Animation showing the path of six of Neptune’s L4 trojans in a rotating frame with a period equal to Neptune’s orbital period.. Credit: Tony Dunn/Wikipedia Commons

From this, said Lin, they derived two possible explanations:

“The L4 “Trojan Cloud” is wide in orbital inclination space. If it is not as wide as we thought before,  the two observational results are statistically possible to generate from the same intrinsic inclination distribution. The previous study suggested >11 degrees width of inclination, and most likely is ~20 degrees. Our study suggested that it should be 7 to 27 degrees, and the most likely is ~ 10 degrees.”

“[Or], the previous surveys were used larger aperture telescopes and detected fainter NT than we found in PS1. If the fainter (smaller) NTs have wider inclination distribution than the larger ones, which means the smaller NTs are dynamically “hotter” than the larger NTs, the disagreement can be explained.”

According to Lin, this difference is significant because the inclination distribution of NTs is related to their formation mechanism and environment. Those that have low orbital inclinations could have formed at Neptune’s Lagrange Points and eventually grew large enough to become Trojans asteroids.

Illustration of the Sun-Earth Lagrange Points. Credit: NASA
Illustration of the Sun-Earth Lagrange Points. Credit: NASA

On the other hand, wide inclinations would serve as an indication that the Trojans were captured into the Lagrange Points, most likely during Neptune’s planetary migration when it was still young. And as for those that have wide inclinations, the degree to which they are inclined could indicate how and where they would have been captured.

“If the width is ~ 10 degrees,” he said, “the Trojans can be captured from a thin (dynamically cold) planetesimal disk. On the other hand, if the Trojan cloud is very wide (~ 20 degrees), they have to be captured from a  thick (dynamically hot) disk. Therefore, the inclination distribution give us an idea of how early Solar system looks like.”

In the meantime, Li and his research team hope to use the Pan-STARR facility to observe more NTs and hundreds of other Centaurs, Trans-Neptunian Objects (TNOs) and other distant Solar System objects. In time, they hope that further analysis of other Trojans will shed light on whether there truly are two families of Neptune Trojans.

This was all made possible thanks to the PS1 survey. Unlike most of the deep surveys, which are only ale to observe small areas of the sky, the PS1 is able to monitor the whole visible sky in the Northern Hemisphere, and with considerable depth. Because of this, it is expected to help astronomers spot objects that could teach us a great deal about the history of the early Solar System.

Further Reading: arXiv