Lucy will explore the Jupiter Trojan asteroids– believed to be “fossils of world formation.” Credit: NASAs Goddard Space Flight Center
Even before its launch in October 2021, NASAs Lucy mission was already on course to break records by going to more asteroids than any previous mission. Now, the mission can include one more asteroid to the list, after a surprise result from a long-running observation campaign.
Lucys science team discovered on March 27 that the tiniest of the objectives Trojan asteroid targets, Polymele, has a satellite of its own. On that day, Polymele was anticipated to pass in front of a star. This would permit the group to observe the star blink out as the asteroid briefly blocked, or occulted, it. The Lucy group planned to determine the area, size, and shape of Polymele with unmatched precision while it was described by the star behind it. To do so, they spread 26 groups of amateur and expert astronomers throughout the path where the occultation would be noticeable.
A graphic showing the observed separation of asteroid Polymele from its discovered satellite. Credit: NASAs Goddard Space Flight
These occultation projects have been tremendously successful in the past, providing important details to the objective on its asteroid targets, but this day would hold an unique perk.
We were delighted that 14 groups reported observing the star blink out as it passed behind the asteroid. However, as we examined the information, we saw that 2 of the observations were not like the others,” stated Marc Buie, Lucy occultation science lead at the Southwest Research Institute, which is headquartered in San Antonio. “Those 2 observers identified a things around 200 km (about 124 miles) away from Polymele. It had to be a satellite.”
A graphic showing the observed separation of asteroid Polymele from its discovered satellite. Credit: NASAs Goddard Space Flight
Utilizing the occultation information, the researchers determined that this satellite is roughly 3 miles (5 km) in size, orbiting Polymele, which is itself around 17 miles (27 km) along its best axis. The observed distance in between the two bodies was around 125 miles (200 km).
Following planetary calling conventions, the satellite will not be released an official name till the group can determine its orbit. As the satellite is too near to Polymele to be clearly seen by Earth-based or Earth-orbiting telescopes– without the aid of a luckily positioned star– that decision will have to wait until Lucy approaches the asteroid in 2027, unless the team gets lucky with future occultation efforts before then.
At the time of the observation, Polymele was 480 million miles (770 million km) from Earth. Those distances are roughly equivalent to discovering a quarter on a sidewalk in Los Angeles– while attempting to identify it from a high-rise building thousands of miles away in Manhattan.
Utilizing the occultation information, the team assessed that this satellite is approximately 3 miles (5 km) in diameter, orbiting Polymele, which is itself around 17 miles (27 km) along its widest axis. The observed range between the two bodies was about 125 miles (200 km). Credit: NASAs Goddard Space Flight Center
The Lucy team originally prepared to check out one main belt asteroid and 6 Trojan asteroids, a previously unexplored population of asteroids that follow and lead Jupiter in its orbit around the Sun. Now with this brand-new satellite, Lucy is on track to check out nine asteroids on this exceptional 12-year trip.
” Lucys tagline started: 12 years, 7 asteroids, one spacecraft,” said Lucy program scientist Tom Statler at NASA Headquarters in Washington. “We keep needing to change the tagline for this mission, however thats a good problem to have.”
As it turns out, Eurybates, one of the asteroids along Lucys course, has a little satellite. The asteroids emerged from behind the Sun in July 2020, and considering that then, the Lucy team has actually been able to observe the satellite with Hubble on multiple events, enabling the group to specifically define the satellites orbit and enabling the little satellite to finally get a main name– Queta.
Lucys principal detective is based out of the Boulder, Colorado, branch of Southwest Research Institute, headquartered in San Antonio, Texas. Lucy is the 13th objective in NASAs Discovery Program.
Lucys science team discovered on March 27 that the tiniest of the objectives Trojan asteroid targets, Polymele, has a satellite of its own. The Lucy group initially planned to visit one primary belt asteroid and 6 Trojan asteroids, a formerly undiscovered population of asteroids that lead and follow Jupiter in its orbit around the Sun. Now with this brand-new satellite, Lucy is on track to go to 9 asteroids on this remarkable 12-year trip.
As it turns out, Eurybates, one of the asteroids along Lucys course, has a small satellite. The asteroids emerged from behind the Sun in July 2020, and since then, the Lucy team has actually been able to observe the satellite with Hubble on multiple occasions, allowing the team to exactly specify the satellites orbit and permitting the little satellite to finally get an official name– Queta.
