NASAのボランティアが15個の珍しい “活動的な小惑星” を発見(NASA Volunteers Find Fifteen Rare “Active Asteroids”)

2024-03-16

2024-03-15 NASA

NASAのアクティブアステロイドプロジェクトは、15個の小惑星で彗星のような尾やガスと塵のエンベロープなどの「活動」を発見し、太陽系に関する従来の考え方に挑戦しています。これらの15個の稀なオブジェクトを見つけるために、8000人以上のボランティアがチリのビクトルM.ブランコ望遠鏡のダークエネルギーカメラ（DECam）から43万枚の画像を調査しました。これらの活動する小惑星の研究は、太陽系の形成と進化、地球上の水の起源などについて科学者に教えるとともに、将来の宇宙探査を支援する可能性があります。

＜関連情報＞

活動小惑星市民科学プログラム：概要と最初の成果 The Active Asteroids Citizen Science Program: Overview and First Results

Colin Orion Chandler, Chadwick A. Trujillo, William J. Oldroyd, Jay K. Kueny, William A. Burris^, Henry H. Hsieh, Jarod A. DeSpain, Nima Sedaghat, Scott S. Sheppard, Kennedy A. Farrell ,＋
The Astronomical Journal Published:2024 March 14
DOI:10.3847/1538-3881/ad1de2

Abstract

We present the Citizen Science program Active Asteroids and describe discoveries stemming from our ongoing project. Our NASA Partner program is hosted on the Zooniverse online platform and launched on 2021 August 31, with the goal of engaging the community in the search for active asteroids—asteroids with comet-like tails or comae. We also set out to identify other unusual active solar system objects, such as active Centaurs, active quasi-Hilda asteroids (QHAs), and Jupiter-family comets (JFCs). Active objects are rare in large part because they are difficult to identify, so we ask volunteers to assist us in searching for active bodies in our collection of millions of images of known minor planets. We produced these cutout images with our project pipeline that makes use of publicly available Dark Energy Camera data. Since the project launch, roughly 8300 volunteers have scrutinized some 430,000 images to great effect, which we describe in this work. In total, we have identified previously unknown activity on 15 asteroids, plus one Centaur, that were thought to be asteroidal (i.e., inactive). Of the asteroids, we classify four as active QHAs, seven as JFCs, and four as active asteroids, consisting of one main-belt comet (MBC) and three MBC candidates. We also include our findings concerning known active objects that our program facilitated, an unanticipated avenue of scientific discovery. These include discovering activity occurring during an orbital epoch for which objects were not known to be active, and the reclassification of objects based on our dynamical analyses.