Asteroid observations with the Hubble Space Telescope. II. Duplicity search and size measurements for 6 asteroids

Paolo Tanga (1, 2) , Daniel Hestroffer (3) , Alberto Cellino (2) , M. Lattanzi (2) , Mario Di Martino (2) , V. Zappalà (2)

1 LG - Laboratoire Gemini
2 INAF, Osservatorio Astronomico di Torino, Strada Osservatorio 20, 10025 Pino Torinese (TO), Italy
3 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides

We present the results of the observations of five Main Belt asteroids and one Trojan obtained using the Fine Guidance Sensors (FGS) of the Hubble Space Telescope. For each object, estimates of the spin axis orientation, angular size and overall shape, as well as possible indications of a binary structure, are derived. This enables the computation of new physical ephemerides. While the data concerning (63) Ausonia are clearly compatible with a three-axis ellipsoidal model, other objects show more complex shapes. (15) Eunomia, (43) Ariadne and (44) Nysa could in fact be double asteroids, or highly irregular bodies. The data concerning (624) Hektor are not conclusive as to its supposed binary nature, even if they agree with the signal of a single body. The results presented here strongly support the outstanding capabilities of the FGS for asteroid measurements, provided that the observations are performed over a sufficient time interval.

Domaines: Astrophysique [astro-ph]; Planète et Univers [physics]

Paolo Tanga, Daniel Hestroffer, Alberto Cellino, M. Lattanzi, Mario Di Martino, et al.. Asteroid observations with the Hubble Space Telescope. II. Duplicity search and size measurements for 6 asteroids. Astronomy and Astrophysics - A&A, 2003, 401, pp.733-741. ⟨hal-03786102⟩