A cometary origin for CO in the stratosphere of Saturn?

被引：37
作者：
Cavalie, T. [1 ]
Hartogh, P. [1 ]
Billebaud, F. [2 ,3 ]
Dobrijevic, M. [2 ,3 ]
Fouchet, T. [4 ]
Lellouch, E. [4 ]
Encrenaz, T. [4 ]
Brillet, J. [2 ,3 ]
Moriarty-Schieven, G. H. [5 ]
机构：
[1] Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany
[2] Univ Bordeaux, LAB, Bordeaux, France
[3] CNRS, INSU, UMR 5804, F-33271 Floirac, France
[4] Observ Paris, LESIA, F-92195 Meudon, France
[5] Herzberg Inst Astrophys, Natl Res Council, Victoria, BC V9E 2E7, Canada
来源：
ASTRONOMY & ASTROPHYSICS | 2010年 / 510卷
关键词：
planets and satellites: individual: Saturn; radio lines: planetary systems; CARBON-MONOXIDE; WATER-VAPOR; ATMOSPHERE; JUPITER; URANUS; SHOEMAKER-LEVY-9; PHOTOCHEMISTRY; OXYGEN; IMPACT;
D O I：
10.1051/0004-6361/200912909
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
Context. The CO(3-2) line has been observed in the atmosphere of Saturn. The CO(3-2) observation proves that an external source of CO exists in the stratosphere of the planet. Aims. We attempt to constrain the type and magnitude of the external source of CO in the atmosphere of Saturn, by observing the emission core of the CO(6-5) line. Methods. We observed the CO(6-5) line at the limbs of Saturn. We analysed the observations by means of a 1-D transport model of the atmosphere of Saturn, coupled with a radiative transfer model. Results. We obtained a high signal-to-noise ratio spectrum that confirms the existence of an external source of CO in the stratosphere of Saturn. We demonstrated that a cometary origin of CO is the most probable, an impact occurring 220 +/- 30 years ago and depositing (2.1 +/- 0.4) x 10(15) g of CO above 0.1 mbar. However, we cannot totally reject the possibility of CO originating (at least partially) in a steady source. Conclusions. Complete photochemical modelling of the oxygen compounds is required to determine realistic error bars of the inferred quantities and to conclude on the origin of CO.
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页数：7
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