Water production and release in Comet C/1995 O1 Hale-Bopp

Citation
N. Dello Russo et al., Water production and release in Comet C/1995 O1 Hale-Bopp, ICARUS, 143(2), 2000, pp. 324-337
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ICARUS
ISSN journal
0019-1035 → ACNP
Volume
143
Issue
2
Year of publication
2000
Pages
324 - 337
Database
ISI
SICI code
0019-1035(200002)143:2<324:WPARIC>2.0.ZU;2-4
Abstract
Water (H2O) was detected in Comet C/1995 O1 Hale-Bopp on 10 dates between U T January 21.8 and May 1.2, 1997, using high-resolution infrared spectrosco py. This is the first study of the heliocentric dependence of water release d from a comet using direct detection of H2O itself. Production rates and r otational temperatures were measured, and the derived heliocentric dependen ce for the water production rate is Q = (8.35 +/- 0.13) x 10(30) [R-h((-1.8 8+/-0.18))] molecules s(-1). The spatial distribution of H2O molecules in t he coma is consistent with water being released directly from the nucleus w ithin 1.5 AU of the Sun, although release of a small fraction from icy grai ns cannot be excluded. When our derived water production rates are compared to the production of native carbon monoxide and dust, we obtain a dust to ice mass ratio of 5.1 +/- 1.2 within a heliocentric distance of 1.5 AU. The abundance of H2O provides a benchmark for the volatile inventory in Hale-B opp and, when compared to interstellar and nebular material, helps constrai n the origin of cometary ices and their processing histories. These product ion rates derived from the direct detection of H2O provide a sound basis wi th which water production rates inferred by indirect methods can be compare d. (C) 2000 Academic Press.