地球から1100万キロ離れた場所で、宇宙船と小惑星が意図的に衝突したときの余波を、エジンバラの科学者を含むチームが研究した結果です。 The aftermath of a deliberate collision between a spacecraft and an asteroid, 11 million kilometers from Earth, has been studied by a team that includes Edinburgh scientists.
2023-03-22 エディンバラ大学
◆DART宇宙船のディモルフォス小惑星への衝突は、わずか一瞬でしたが、これによって数年間にわたって小惑星の研究に与える影響が感じられるでしょう。物理学と天文学の学校の科学者たちは、ヨーロッパ南天天文台の超大型望遠鏡を使用して、ディモルフォスとの最初の衝突後1か月間、放出された物質の進化を追跡しました。 衝突前よりも放出された物質の雲は青みがかっており、非常に微細な塵粒子で構成されている可能性があることを示しています。
◆研究チームは、雲から発展する他の構造物-塊、螺旋、太陽放射によって押し出された塵の長い尾-を発見しました。螺旋と尾は最初の雲よりも赤みがかっており、大きな塵粒子で構成されている可能性があります。チームはまた、衝撃によって露出した氷から出てくる酸素や水分子を探しましたが、何も見つかりませんでした。
＜関連情報＞
- https://www.ed.ac.uk/news/2023/spacecraft-collision-with-asteroid-impact-analysed
- https://www.aanda.org/articles/aa/full_html/2023/03/aa45960-23/aa45960-23.html
VLT/MUSEによるDART衝突噴出物の形態とスペクトル特性 Morphology and spectral properties of the DART impact ejecta with VLT/MUSE
C. Opitom, B. Murphy, C. Snodgrass, S. Bagnulo, S. F. Green, M. M. Knight, J. de Léon, J.-Y. Li and D. Gardener
Astronomy & Astrophysics Published:21 March 2023
DOI:https://doi.org/10.1051/0004-6361/202345960
Abstract
Context. On September 26, 2022, the NASA DART mission impacted the asteroid Dimorphos, the smaller component of the Didymos binary asteroid system. This provided a unique opportunity to observe, in real time, the evolution of the ejecta cloud produced by the impact and the formation of a tail.
Aims. We present observations performed with the MUSE instrument at the Very Large Telescope to characterise the morphology, spectral properties, and evolution of the ejecta. The Didymos system was observed with MUSE on 11 nights from just before impact to almost one month post-impact, using both wide-field observations without adaptive optics and narrow-field observations with adaptive optics.
Methods. We produced white light images that were used to study the morphology of the ejecta at different spatial scales. The spectral information was used to search for gas emission from either exposed ice or propellant, and to study the spatial and temporal variation of the ejecta dust reflectance through reflectance maps.
Results. We searched for, but did not detect, emission from [OI], Xe, NH2, and H2O+ in a 1′×1′ field of view in our observations starting almost 4h after impact. We detected a number of morphological features, including a short-lived ejecta cloud visible on September 27 towards the east, spirals, clumps, and a tail that started forming only a few hours after impact. The analysis of the reflectance maps showed that the initial ejecta was bluer than the system before impact, while the tail and spirals were redder than the initial ejecta, consistent with them being made of larger particles. Over the few weeks following impact, the tail became redder. No significant colour differences could be seen between the clumps and the initial ejecta.
