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Main-belt comets in the Palomar Transient Factory survey – I. The search for extendedness

Waszczak, A. and Ofek, E. O. and Aharonson, O. and Kulkarni, S. R. and Polishook, D. and Bauer, J. M. and Levitan, D. and Sesar, B. and Laher, R. and Surace, J. (2013) Main-belt comets in the Palomar Transient Factory survey – I. The search for extendedness. Monthly Notices of the Royal Astronomical Society, 433 (4). pp. 3115-3132. ISSN 0035-8711.

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Cometary activity in main-belt asteroids probes the ice content of these objects and provides clues to the history of volatiles in the inner Solar system. We search the Palomar Transient Factory survey to derive upper limits on the population size of active main-belt comets (MBCs). From data collected from 2009 March through 2012 July, we extracted ∼2 million observations of ∼220 thousand known main-belt objects (40 per cent of the known population, down to ∼1-km diameter) and discovered 626 new objects in multinight linked detections. We formally quantify the ‘extendedness’ of a small-body observation, account for systematic variation in this metric (e.g. due to on-sky motion) and evaluate this method's robustness in identifying cometary activity using observations of 115 comets, including two known candidate MBCs and six newly discovered non-MBCs (two of which were originally designated as asteroids by other surveys). We demonstrate a 66 per cent detection efficiency with respect to the extendedness distribution of the 115 sampled comets, and a 100 per cent detection efficiency with respect to extendedness levels greater than or equal to those we observed in the known candidate MBCs P/2010 R2 (La Sagra) and P/2006 VW_(139). Using a log-constant prior, we infer 95 per cent confidence upper limits of 33 and 22 active MBCs (per million main-belt asteroids down to ∼1-km diameter), for detection efficiencies of 66 and 100 per cent, respectively. In a follow-up to this morphological search, we will perform a photometric (disc-integrated brightening) search for MBCs.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper 10.1093/mnras/stt951 DOIArticle
Ofek, E. O.0000-0002-6786-8774
Aharonson, O.0000-0001-9930-2495
Kulkarni, S. R.0000-0001-5390-8563
Sesar, B.0000-0002-0834-3978
Laher, R.0000-0003-2451-5482
Surace, J.0000-0001-7291-0087
Additional Information:© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 May 30. Received 2013 May 26; in original form 2013 January 8. First published online: June 24, 2013. We thank the referee for useful comments. This work is based on data obtained with the 1.2-m Samuel Oschin Telescope at Palomar Observatory as part of the Palomar Transient Factory project, a scientific collaboration between the California Institute of Technology, Columbia University, Las Cumbres Observatory, Lawrence Berkeley National Laboratory, the National Energy Research Scientific Computing Center, the University of Oxford and the Weizmann Institute of Science (WIS). EOO is incumbent of the Arye Dissentshik career development chair and is grateful for support via a grant from the Israeli Ministry of Science. OA and EOO wish to thank the Helen Kimmel Center for Planetary Science at WIS. SRK and his group are partially supported by NSF grant AST-0507734. DP is grateful to the AXA research fund.
Group:Palomar Transient Factory, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Ministry of Science (Israel)UNSPECIFIED
Subject Keywords:surveys – comets: general –minor planets, asteroids: general
Issue or Number:4
Record Number:CaltechAUTHORS:20130903-160604685
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41072
Deposited By: Tony Diaz
Deposited On:04 Sep 2013 22:20
Last Modified:03 Mar 2020 13:01

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