New Limits to CO Outgassing in Centaurs
Abstract
Centaurs are small Solar system objects orbiting between Jupiter and Neptune. They are widely believed to be escapees from the trans-Neptunian region on their way to become Jupiter-family comets. Indeed, some Centaurs exhibit the characteristic cometary appearance. The sublimation of carbon monoxide has been proposed as a driver of activity in distant comets, but no strong detection of gaseous CO in a Centaur other than 29P/Schwassmann-Wachmann 1 has been reported to date. Here we report the results of a deep search for CO outgassing in three Centaurs: (315898), (342842), and (382004). Our survey was carried out using the Caltech Submillimeter Observatory on nine nights in late 2011. The targeted rotational line J(2–1) of CO is undetected in all three objects in spite of high instrumental sensitivity. We find the model-dependent 3σ upper limits to the CO production rate of 2.13 × 10^(27) molecules s^(−1) for (315898), 1.32 × 10^(27) molecules s^(−1) for (342842), and 1.17 × 10^(27) molecules s^(−1) for (382004), which are among the most sensitive obtained to date. These upper limits are consistently analysed in the context of published CO data of 14 Centaurs and one well-observed long-period comet, C/1995 O1 (Hale-Bopp), and support an earlier suggestion that the surfaces of most Centaurs are not dominated by exposed CO ice.
Additional Information
© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 September 2. Received 2016 September 1; in original form 2015 September 4. Published: 06 September 2016. The majority of the work of MD was performed at Caltech and supported through a Jansky Fellowship of the National Radio Astronomy Observatory. MD also greatly appreciates earlier support from UCLA, and is indebted to Lech Walesa, the leader of Solidarnosc, for his key role in the fall of communism in Europe, which made it possible to conduct this study. DJ appreciates support from NASA's Origins programme. The data presented herein were obtained at the CSO, supported through NSF grant AST-0540882 at the time of the observations. The authors thank the telescope staff and I-Ting Ho for support, Nicolas Biver for comments and for providing published CO production rates of comet Hale-Bopp, and an anonymous referee for helpful suggestions.Attached Files
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Additional details
- Eprint ID
- 78516
- Resolver ID
- CaltechAUTHORS:20170623-105430763
- National Radio Astronomy Observatory
- NASA
- AST-0540882
- NSF
- Created
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2017-06-23Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field