456P/Panstars, an active main-belt asteroid first discovered in 2021, is repeatedly active, and its activity is linked to volatile ice formations, according to new observations from the Magellan-Baade and Lowell Discovery telescopes. It is likely that this is caused by sublimation.
456P/PanSTARS image taken on October 3, 2024 with the Magellan Baade Telescope in Chile and with the Lowell Discovery Telescope in Arizona on October 26, 2024. At the center of each image is the comet’s head or nucleus, the tail extends to the right. Image credits: Scott S. Sheppard / Carnegie Institution for Science / Audrey Thirouin, Lowell Observatory / Henry H. Hsieh, Planetary Science Institute.
“Main-belt comets are icy objects found in the asteroid belt between Mars and Jupiter, rather than outside the cold solar system, where icy objects would normally be expected,” said Henry Hsieh, senior scientist at the Planetary Science Institute.
“They have comet-like features, such as tails that extend away from the sun and fuzzy clouds as the sun’s heat evaporates the ice.”
These objects were first discovered in 2006 at the University of Hawaii by Dr. Hsieh and his then-doctoral supervisor, Professor David Jewitt.
“Main-belt comets belong to a larger group of Solar System objects known as active asteroids, which look like comets but have asteroid-like orbits in the warm inner Solar System,” the astronomers said.
“This large group includes not only objects that emit dust from evaporated ice, but also objects that have clouds or tails of ejected dust from collisions or rapid rotation.”
“Both main-belt comets and active asteroids in general are still relatively rare, but scientists are discovering them.”
456P/PANSTARRS was discovered as P/2021 L4 (PANSTARRS) through observations by Pan-STARRS1 on June 9 and 14, 2021, and observations by Canada, France, and Hawaii telescopes on June 14, 2021.
Dr. Hsieh and his co-authors observed the object twice in October 2024 using the Magellan-Baade Telescope and the Lowell Discovery Telescope, establishing its status as a main-belt comet.
“This object is not just an asteroid that experienced a one-off event, but is essentially an active icy object, like other comets in the outer solar system,” Hsieh said.
If 456P/PANSTARRS’s activity is due to something other than ice evaporation, its tail would be expected to appear only once, randomly, and not repeatedly as it approaches the Sun.
On the other hand, icy objects heat up every time they approach the sun, and the evaporated ice is carried away with the dust.
As the object moves away from the sun and cools, it ceases to be active.
Observations of repeated dust ejection activity during their approach to the Sun are currently considered the best and most reliable method of identifying main-belt comets.
“Confirmed main-belt comets are still largely unknown,” Dr. Xie said.
“We want to grow the population so we can understand more clearly what its broader characteristics are, such as its size, active period, and distribution within the asteroid belt. We will be able to better utilize them to track ice within the asteroid belt and across the solar system.”
of findings Published in American Astronomical Society Research Notes.
_____
Henry H. Shea others. 2024. Recurrence activity of main belt comet 456P/Panstars (P/2021 L4) confirmed. Resolution memo AAS 8,283;doi: 10.3847/2515-5172/ad90a6
This article is a reprint of a press release provided by the Planetary Science Institute.
Source: www.sci.news
