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dc.contributor.authorJewitt, David
dc.contributor.authorKim, Yoonyoung
dc.contributor.authorLuu, Jane
dc.contributor.authorRajagopal, Jayadev
dc.contributor.authorKotulla, Ralf
dc.contributor.authorRidgway, Susan
dc.contributor.authorLiu, Wilson
dc.date.accessioned2020-03-16T10:00:36Z
dc.date.available2020-03-16T10:00:36Z
dc.date.issued2019-05-06
dc.description.abstractWe present imaging and spectroscopic observations of 6478 Gault, a ~6 km diameter inner main-belt asteroid currently exhibiting strong, comet-like characteristics. Three distinct tails indicate that ultra-slow dust (ejection speed 0.15 ± 0.05 m s−1) was emitted from Gault in separate episodes beginning UT 2018 October 28 ± 5 (Tail A), UT 2018 December 31 ± 5 (Tail B), and UT 2019 February 10 ± 7 (Tail C), with durations of ΔT ~ 10–20 days. With a mean particle radius 200 μm, the estimated masses of the tails are M A ~ 4 × 107 kg, M B ~ 6 × 106 kg, and M C ~ 6 × 105 kg, respectively, and the mass-loss rates from the nucleus are 20–40 kg s−1 for Tail A, 4–6 kg s−1 for Tail B, and ~0.4 kg s−1 for Tail C. In its optical colors Gault is more similar to C-type asteroids than to S-types, even though the latter are numerically dominant in the inner asteroid belt. A spectroscopic upper limit to the production of gas is set at 1 kg s−1. Discrete emission in three protracted episodes effectively rules out an impact origin for the observed activity. Sublimation driven activity is unlikely given the inner-belt orbit and the absence of detectable gas. In any case, sublimation would not easily account for the observed multiple ejections. The closest similarity is between Gault and active asteroid 311P/(2013 P5), an object showing repeated but aperiodic ejections of dust over a 9 month period. While Gault is 10 times larger than 311P/(2013 P5), and the relevant timescale for spin-up by radiation torques is ~100 times longer, its properties are likewise most consistent with episodic emission from a body rotating near breakup.en_US
dc.identifier.citationJewitt, D.; Kim, Y.; Luu, J.; Rajagopal, J.; Kotulla, R.; Ridgway, S.; Liu, W. (2019) Episodically Active Asteroid 6478 Gault. <i>Astrophysical Journal Letters, 876</i>, (2), 1-11en_US
dc.identifier.cristinIDFRIDAID 1714833
dc.identifier.doi10.3847/2041-8213/ab1be8
dc.identifier.issn2041-8205
dc.identifier.issn2041-8213
dc.identifier.urihttps://hdl.handle.net/10037/17745
dc.language.isoengen_US
dc.publisherIOP Publishingen_US
dc.relation.journalAstrophysical Journal Letters
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2019 The American Astronomical Societyen_US
dc.subjectVDP::Mathematics and natural science: 400::Physics: 430::Astrophysics, astronomy: 438en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430::Astrofysikk, astronomi: 438en_US
dc.titleEpisodically Active Asteroid 6478 Gaulten_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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