Cometary activity in 2060 Chiron at minimum brightness

SILVA, A. M.; CELLONE, S. A.

PLANETARY AND SPACE SCIENCE

Elsevier Ltd.

Año: 2001 vol. 49 p. 1325 - 1330

0032-0633

We present two-colour CCD imaging of 2060 Chiron obtained between 1996 and 1998 with the 2.15m telescope at CASLEO (San Juan, Argentina). These post-perihelion observations show that Chiron was then near its historical brightness minima, however, a coma was clearly detected. The dynamical state of the coma is studied by means of azimuthally averaged surface brightness profiles, which show the signatures of radiation pressure on the dust grain distribution. Aperture photometry shows an achromatic dimming with an amplitude ~0.09mag in approximately 1h. If due to rotation of the nucleus, this rather high amplitude is used to derive a new value for the nuclear magnitude, m0~6.80mag.