Letter to the Editor
Evidence for water ice and estimate of dust production rate in comet Hale-Bopp at 2.9 AU from the Sun *
E. Lellouch 1,
J. Crovisier 1,
T. Lim 2, 3,
D. Bockelée-Morvan 1,
K. Leech 2,
M.S. Hanner 4,
B. Altieri 2,
B. Schmitt 5,
F. Trotta 5 and
H.U. Keller 6
Received 2 July 1998 / Accepted 14 September 1998
We report observational evidence for water ice in comet C/1995 O1 (Hale-Bopp) when it was at 2.9 AU from the Sun, from emission features at 44 and 65 µm, and possibly an absorption feature at 3.1 µm, observed with ISO/LWS and PHT. We find that icy grains have mean radii of 15 µm within a factor of 2, lifetimes of 2 days, a temperature of 153 K, and a total mass of 2109 kg. From investigation of the continuum spectrum at 43-195 µm, we also infer a production rate of large particles ( 100 µm) dust of about 4104 kg s-1.
Key words: comets: general comet: individual: C/1995 O1 (Hale-Bopp) infrared: solar system
* Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with participation of ISAS and NASA.
Send offprint requests to: J. Crovisier
This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 1998
Online publication: September 30, 1998