Commission F4 Asteroids, Comets & Transneptunian Objects

News

The ESA Hera mission, which will measure in details DART impact outcome and the properties of Didymos through a rendezvous with the system and various close proximity operations, passed successfully the Critical Design Review in November 2022. The primary launch window opens in October 2024 and the mission is on track to meet this date and arrive at Didymos for 6 months of investigations over the first semester of 2027 (https://www.heramission.space/).

Highlights in asteroids, comets & TNOs study in 2022

EVENTS:

The Double Asteroid Redirection Test (DART) arrived at the Didymos system and on 26 September 2022 (UTC) successfully executed its intentional crash into Dimorphos, the satellite of Didymos. The immediate aftermath of the crash was imaged by the LICIACube cubesat contributed to DART by the Italian Space Agency. Telescopes around the globe and in space monitored the resulting ejecta cloud as it evolved into a tail, and measured a roughly half-hour change in Dimorphos’ orbit period around Didymos. Official NASA news releases can be found about the impact into Dimorphos (https://www.nasa.gov/press-release/nasa-s-dart-mission-hits-asteroid-in-first-ever-planetary-defense-test), the announcement of the period change (https://www.nasa.gov/press-release/nasa-confirms-dart-mission-impact-changed-asteroid-s-motion-in-space), and other early results presented at the American Geophysical Union conference in December 2022 (https://www.nasa.gov/feature/early-results-from-nasa-s-dart-mission).

· The Data Release 3 by the Gaia mission (ESA), appeared in June 2022 (https://www.cosmos.esa.int/web/gaia/data-release-3), is the first large scale publication of asteroid astrometry by the mission, for 158,152 small bodies (asteroids of all types, TNOs, natural satellites of the planets), observed over 34 months. It also includes visible spectra for 60,518 asteroids. The survey properties illustrated by two articles appeared in the special issue of Astronomy and Astrophysics devoted to DR3: https://doi.org/10.1051/0004-6361/202243796; https://doi.org/10.1051/0004-6361/202243791. Coupled with improved orbital determinations, GDR3 photometric and spectroscopic data are expected to be a primary source for any advancement in asteroids science in the next years.

· NASA Planetary Decadal Survey highlighted key science questions and identified priority missions, giving high billing to asteroid Planetary Defense missions and mission concepts for comet sample return, a centaur tour, and a Ceres lander (https://nap.nationalacademies.org/catalog/26522/origins-worlds-and-life-a-decadal-strategy-for-planetary-science).

PUBLICATIONS:

More than 1450 peer-reviewed papers were published in 2022 according to NASA-ADS database, including ~900 papers on asteroids, ~400 papers on comets, and ~150 papers on TNOs and Pluto. The most popular topics were investigations of near-Earth asteroids in particular targets of the space missions DART, OSIRIX-Rex, Hayubusa2.

SOME RESULTS:

Composition and origin of asteroid Ryugu from the analysis of its samples after the success of the Jaxa Hayabusa2 sample returning mission: https://www.science.org/doi/10.1126/science.abn8671; https://www.science.org/doi/10.1126/sciadv.add8141; https://www.science.org/doi/10.1126/science.abo0431; https://www.science.org/doi/10.1126/sciadv.abo7239; https://www.science.org/doi/10.1126/science.abn7850; https://www.nature.com/articles/s41550-022-01745-5; https://www.science.org/doi/10.1126/science.abj8624 .

First full impact simulations of cratering on low-gravity asteroids: formation of the crater produced by the Hayabusa2 SCI and implications on Ryugu’s surface properties and age: https://www.nature.com/articles/s41467-022-34540-x

Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu: https://www.nature.com/articles/s41467-022-32288-y.

First results of the Calern Asteroid Polarimetric Survey, one of the major currently active projects aimed at increasing the available database of asteroid polarimetric data: https://doi.org/10.1051/0004-6361/202142960.

The discovery and characterization of a surprisingly large a kilometer sized asteroid inside the orbit of Venus: https://doi.org/10.1093/mnrasl/slac089.