학술논문
Optical monitoring of the Didymos-Dimorphos asteroid system with the Danish telescope around the DART mission impact
Document Type
Working Paper
Author
Rożek, Agata; Snodgrass, Colin; Jørgensen, Uffe G.; Pravec, Petr; Bonavita, Mariangela; Rabus, Markus; Khalouei, Elahe; Longa-Peña, Penélope; Burgdorf, Martin J.; Donaldson, Abbie; Gardener, Daniel; Crake, Dennis; Sajadian, Sedighe; Bozza, Valerio; Skottfelt, Jesper; Dominik, Martin; Fynbo, J.; Hinse, Tobias C.; Hundertmark, Markus; Rahvar, Sohrab; Southworth, John; Tregloan-Reed, Jeremy; Kretlow, Mike; Rota, Paolo; Peixinho, Nuno; Andersen, Michael; Amadio, Flavia; Barrios-López, Daniela; Baeza, Nora Soledad Castillo
Source
Subject
Language
Abstract
The NASA's Double-Asteroid Redirection Test (DART) was a unique planetary defence and technology test mission, the first of its kind. The main spacecraft of the DART mission impacted the target asteroid Dimorphos, a small moon orbiting asteroid (65803) Didymos, on 2022 September 26. The impact brought up a mass of ejecta which, together with the direct momentum transfer from the collision, caused an orbital period change of 33 +/- 1 minutes, as measured by ground-based observations. We report here the outcome of the optical monitoring campaign of the Didymos system from the Danish 1.54 m telescope at La Silla around the time of impact. The observations contributed to the determination of the changes in the orbital parameters of the Didymos-Dimorphos system, as reported by arXiv:2303.02077, but in this paper we focus on the ejecta produced by the DART impact. We present photometric measurements from which we remove the contribution from the Didymos-Dimorphos system using a H-G photometric model. Using two photometric apertures we determine the fading rate of the ejecta to be 0.115 +/- 0.003 mag/d (in a 2" aperture) and 0.086 +/- 0.003 mag/d (5") over the first week post-impact. After about 8 days post-impact we note the fading slows down to 0.057 +/- 0.003 mag/d (2" aperture) and 0.068 +/- 0.002 mag/d (5"). We include deep-stacked images of the system to illustrate the ejecta evolution during the first 18 days, noting the emergence of dust tails formed from ejecta pushed in the anti-solar direction, and measuring the extent of the particles ejected sunward to be at least 4000 km.
Comment: 20 pages, 6 figures. Accepted for publication in The Planetary Science Journal
Comment: 20 pages, 6 figures. Accepted for publication in The Planetary Science Journal