HUBBLE SPACE TELESCOPE OBSERVATIONS OF MAIN-BELT COMET (596) SCHEILA

Journal Article · Fri May 20 00:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/733/1/L4· OSTI ID:21562675

Jewitt, David ^[1]; Weaver, Harold ^[2]; Mutchler, Max ^[3]; Larson, Stephen ^[4]; Agarwal, Jessica ^[5]

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1. Department of Earth and Space Sciences, UCLA, 595 Charles Young Drive East, Box 951567, Los Angeles, CA 90095-1567 (United States)
2. The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States)
3. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
4. Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721-0092 (United States)
5. Institute for Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam (Germany)

We present Hubble Space Telescope Observations of (596) Scheila during its recent dust outburst. The nucleus remained point-like with absolute magnitude H{sub V} = 8.85 {+-} 0.02 in our data, equal to the pre-outburst value, with no secondary fragments of diameter {>=}100 m (for assumed albedos 0.04). We find a coma having a peak scattering cross section {approx}2.2x10{sup 4} km{sup 2}, corresponding to a mass in micron-sized particles of {approx}4x10{sup 7} kg. The particles are deflected by solar radiation pressure on projected spatial scales {approx}2x10{sup 4} km, in the sunward direction, and swept from the vicinity of the nucleus on timescales of weeks. The coma fades by {approx}30% between observations on UT 2010 December 27 and 2011 January 4. The observed mass loss is inconsistent with an origin either by rotational instability of the nucleus or by electrostatic ejection of regolith charged by sunlight. Dust ejection could be caused by the sudden but unexplained exposure of buried ice. However, the data are most simply explained by the impact, at {approx}5 km s{sup -1}, of a previously unknown asteroid {approx}35 m in diameter.

• OSTI ID: 21562675
• Journal Information: Astrophysical Journal Letters, Vol. 733, Issue 1; Other Information: DOI: 10.1088/2041-8205/733/1/L4; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTEROIDS
COMETS
DUSTS