New Active Asteroid 313P/Gibbs

Abstract

We present initial observations of the newly-discovered active asteroid 313P/Gibbs (formerly P/2014 S4), taken to characterize its nucleus and comet-like activity. The central object has a radius $\sim$0.5 km (geometric albedo 0.05 assumed). We find no evidence for secondary nuclei and set (with qualifications) an upper limit to the radii of such objects near 25 m, assuming the same albedo. Both aperture photometry and a morphological analysis of the ejected dust show that mass-loss is continuous at rates $\sim$0.2 to 0.4 kg s${}^{-1}$, inconsistent with an impact origin. Large dust particles, with radii $\sim$50 to 100 $\mu$m, dominate the optical appearance. At 2.4 AU from the Sun, the surface equilibrium temperatures are too low for thermal or desiccation stresses to be responsible for the ejection of dust. No gas is spectroscopically detected (limiting the gas mass loss rate to $<$1.8 kg s${}^{-1}$). However, the protracted emission of dust seen in our data and the detection of another episode of dust release near perihelion, in archival observations from 2003, are highly suggestive of an origin by the sublimation of ice. Coincidentally, the orbit of 313P/Gibbs is similar to those of several active asteroids independently suspected to be ice sublimators, including P/2012 T1, 238P/Read and 133P/Elst-Pizarro, suggesting that ice is abundant in the outer asteroid belt.

24 pages, 7 figures, accepted The Astronomical Journal

References in corpus (18)

• The taxonomic distribution of asteroids from multi-filter all-sky photometric surveys
• The Active Asteroids
• The colours of the Sun
• The formation of Encke meteoroids and dust trail
• Hubble Space Telescope Observations of Main Belt Comet (596) Scheila
• Recurrent Perihelion Activity in (3200) Phaethon
• Collisional Excavation of Asteroid (596) Scheila
• Disintegrating Asteroid P/2013 R3
• The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5
• Hubble Space Telescope Investigation of Main-Belt Comet 133P/Elst-Pizarro
• Main-Belt Comet 238P/Read Revisited
• Interpretation of (596) Scheila's Triple Dust Tails
• Dynamical Constraints on the Origin of Main Belt Comets
• Main-Belt Comet P/2012 T1 (PANSTARRS)
• Rotation State of Comet 103P/Hartley 2 from Radio Spectroscopy at 1 mm
• The dust environment of Main-Belt Comet P/2012 T1 (PANSTARRS)
• Discovery and Characteristics of the Rapidly Rotating Active Asteroid (62412) 2000 SY178 in the Main Belt
• Intermittent dust mass loss from activated asteroid P/2013 P5 (PANSTARRS)

Cited by in corpus (14)

• The Main Belt Comets and Ice in the Solar System
• Asteroid Family Associations of Active Asteroids
• SAFARI: Searching Asteroids For Activity Revealing Indicators
• The Reactivation of Main-Belt Comet 324P/La Sagra (P/2010 R2)
• Observational Constraints on Water Sublimation from 24 Themis and 1 Ceres
• Hubble and Keck Telescope Observations of Active Asteroid 288P/300163 (2006 VW139)
• Nucleus and Mass Loss from Active Asteroid 313P/Gibbs
• X-shooter search for outgassing from Main Belt Comet P/2012 T1 (Pan-STARRS)
• Photometric observations of ecliptic comet 47P/Ashbrook-Jackson and selected quasi-Hilda and main-belt comets at Kyiv Comet Station (MPC code - 585) in 2017
• Study of the physical properties of selected active objects in the main belt and surrounding regions by broadband photometry
• Main-belt comets: sublimation-driven activity in the asteroid belt
• Comet 66P/du Toit: not a near Earth main belt comet
• Nucleus of active asteroid 358P/Pan-STARRS (P/2012 T1)
• Search for Dust Emission from (24) Themis Using the Gemini-North Telescope