Impact flux on Jupiter: From superbolides to large-scale collisions

¹ Física Aplicada I, Universidad del País Vasco UPV/EHU, ETS Ingeniería, Alameda Urquijo s/n, 48013 Bilbao, Spain
e-mail: ricardo.hueso@ehu.es
² Unidad Asociada Grupo Ciencias Planetarias UPV/EHU-IAA(CSIC), 48013 Bilbao, Spain
³ Acquerra Pty. Ltd., 82 Merryville Drive, Murrumbateman NSW 2582, Australia
⁴ Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080-3021, USA
⁵ Physics Department, University of San Carlos, 6000 Cebu City, Philippines
⁶ Association of Lunar and Planetary Observers of Japan, 2-33-12 Misawa, Hino, 191-0032 Tokyo, Japan
⁷ Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando FL 32816-2385, USA
⁸ Department of Earth & Planetary Sciences, University of California Santa Cruz, Santa Cruz CA 95064, USA
⁹ Commission des observations planétaires, Société Astronomique de France, 2 rue de l’Ardèche, 31170 Tournefeuille, France
¹⁰ Astronomy Department, 601 Campbell Hall, University of California, Berkeley CA 94720, USA
¹¹ Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
¹² Space Science Institute, 4750 Walnut Avenue, Suite 205, Boulder CO 80301, USA
¹³ Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91109, USA
¹⁴ National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, 181-8588 Tokyo, Japan
¹⁵ Agrupación astronómica de Sabadell, 08200 Sabadell, Spain

Received: 5 July 2013
Accepted: 27 September 2013

Abstract

Context. Regular observations of Jupiter by a large number of amateur astronomers have resulted in the serendipitous discovery of short bright flashes in its atmosphere, which have been proposed as being caused by impacts of small objects. Three flashes were detected: one on June 3, 2010, one on August 20, 2010, and one on September 10, 2012.

Aims. We show that the flashes are caused by impacting objects that we characterize in terms of their size, and we study the flux of small impacts on Jupiter.

Methods. We measured the light curves of these atmospheric airbursts to extract their luminous energy and computed the masses and sizes of the objects. We ran simulations of impacts and compared them with the light curves. We analyzed the statistical significance of these events in the large pool of Jupiter observations.

Results. All three objects are in the 5−20 m size category depending on their density, and they released energy comparable to the recent Chelyabinsk airburst. Model simulations approximately agree with the interpretation of the limited observations. Biases in observations of Jupiter suggest a rate of 12−60 similar impacts per year and we provide software tools for amateurs to examine the faint signature of impacts in their data to increase the number of detected collisions.

Conclusions. The impact rate agrees with dynamical models of comets. More massive objects (a few 100 m) should impact with Jupiter every few years leaving atmospheric dark debris features that could be detectable about once per decade.