Berlin 2014 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 4: Planeten

EP 4.5: Talk

Tuesday, March 18, 2014, 15:15–15:30, DO24 1.103

The multi-tailed asteroid P/2013 P5 — •Jessica Agarwal¹, David Jewitt², Harold Weaver³, Max Mutchler⁴, and Stephen Larson⁵ — ¹Max-Planck-Institut für Sonnensystemforschung, Göttingen, Deutschland — ²University of California, Los Angeles, USA — ³The Johns Hopkins University Applied Physics Laboratory, Laurel, USA — ⁴Space Telescope Science Institute, Baltimore, USA — ⁵University of Arizona, Tucson, USA

We present Hubble Space Telescope observations of the active asteroid P/2013 P5, (P5) and discuss possible mechanisms for its activation. P5 is an inner Main Belt asteroid <240m in diameter, and was discovered in August 2013 by the Pan-STARRS sky survey, following a brightening episode that produced a comet-like appearance. We obtained high-resolution images of P5 with the Hubble Space Telescope and found six tails emerging from the nucleus. Each tail contained dust ejected at a specific date over the spring and summer of 2013. Since the activity of this asteroid is episodic, we exclude an impact as the cause. Also sublimation of subsurface ices is an unlikely cause of activity, because temperatures in the inner Main Belt are too high for asteroids to harbour ices over the age of the solar system. We therefore think that the most likely cause of the activity is rotation-driven break-up, where YORP or other torques have increased the spin rate of the asteroid to the point where surface material breaks loose and escapes the gravity field of the nucleus. P5 is the second asteroid (P/2010 A2 being the first) with indications that we might witness such a process.