OBSERVATIONAL AND DYNAMICAL CHARACTERIZATION OF MAIN-BELT COMET P/2010 R2 (La Sagra)
- Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu HI 96822 (United States)
- Department of Astronomy, Faculty of Mathematics, University of Belgrade, Studentski trg 16, 11000 Belgrade (Serbia)
- Institute of Astronomy, National Central University, 300 Jhongda Rd, Jhongli 32001, Taiwan (China)
- Astronomy Research Centre, Queens University Belfast, Belfast BT7 1NN (United Kingdom)
- Department of Physics, P.O. Box 64, 00014 University of Helsinki (Finland)
- Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
- Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)
- Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States)
- Department of Physics and Astronomy, Northern Arizona University, 602 South Humphreys Street, Flagstaff, AZ 86011 (United States)
We present observations of the recently discovered comet-like main-belt object P/2010 R2 (La Sagra) obtained by Pan-STARRS1 and the Faulkes Telescope-North on Haleakala in Hawaii, the University of Hawaii 2.2 m, Gemini-North, and Keck I telescopes on Mauna Kea, the Danish 1.54 m telescope (operated by the MiNDSTEp consortium) at La Silla, and the Isaac Newton Telescope on La Palma. An antisolar dust tail is observed to be present from 2010 August through 2011 February, while a dust trail aligned with the object's orbit plane is also observed from 2010 December through 2011 August. Assuming typical phase darkening behavior, P/La Sagra is seen to increase in brightness by >1 mag between 2010 August and December, suggesting that dust production is ongoing over this period. These results strongly suggest that the observed activity is cometary in nature (i.e., driven by the sublimation of volatile material), and that P/La Sagra is therefore the most recent main-belt comet to be discovered. We find an approximate absolute magnitude for the nucleus of H{sub R} = 17.9 {+-} 0.2 mag, corresponding to a nucleus radius of {approx}0.7 km, assuming an albedo of p = 0.05. Comparing the observed scattering surface areas of the dust coma to that of the nucleus when P/La Sagra was active, we find dust-to-nucleus area ratios of A{sub d} /A{sub N} = 30-60, comparable to those computed for fellow main-belt comets 238P/Read and P/2008 R1 (Garradd), and one to two orders of magnitude larger than for two other main-belt comets (133P/Elst-Pizarro and 176P/LINEAR). Using optical spectroscopy to search for CN emission, we do not detect any conclusive evidence of sublimation products (i.e., gas emission), finding an upper limit CN production rate of Q{sub CN} < 6 Multiplication-Sign 10{sup 23} mol s{sup -1}, from which we infer an H{sub 2}O production rate of Q{sub H{sub 2O}} < 10{sup 26} mol s{sup -1}. Numerical simulations indicate that P/La Sagra is dynamically stable for >100 Myr, suggesting that it is likely native to its current location and that its composition is likely representative of other objects in the same region of the main belt, though the relatively close proximity of the 13:6 mean-motion resonance with Jupiter and the (3,-2,-1) three-body mean-motion resonance with Jupiter and Saturn mean that dynamical instability on larger timescales cannot be ruled out.
- OSTI ID:
- 22034653
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 143, Issue 5; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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