OSSOS

XI. No active centaurs in the Outer Solar System Origins Survey

¹ Institut UTINAM, UMR6213 / CNRS – UBFC, 25000 Besançon, France
e-mail: nahuel.cabral@utinam.cnrs.fr
² Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN, UK
³ Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
⁴ Institute of Astronomy and Astrophysics, Academia Sinica; 11F of AS/NTU Astronomy-Mathematics Building, Nr. 1 Roosevelt Rd., Sec. 4, Taipei 10617, Taiwan
⁵ University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
⁶ Herzberg Astronomy and Astrophysics Research Centre, National Research Council of Canada, 5071 West Saanich Rd, Victoria, British Columbia V9E 2E7, Canada
⁷ Department of Physics and Astronomy, University of Victoria, Elliott Building, 3800 Finnerty Rd, Victoria, BC V8P 5C2, Canada

Received: 3 August 2018
Accepted: 24 September 2018

Abstract

Context. Centaurs are icy objects in transition between the trans-Neptunian region and the inner solar system, orbiting the Sun in the giant planet region. Some centaurs display cometary activity, which cannot be sustained by the sublimation of water ice in this part of the solar system, and has been hypothesized to be due to the crystallization of amorphous water ice.

Aims. In this work, we investigate centaurs discovered by the Outer Solar System Origins Survey (OSSOS) and search for cometary activity. Tentative detections would improve understanding of the origins of activity among these objects.

Methods. We search for comae and structures by fitting and subtracting both point spread functions and trailed point-spread functions from the OSSOS images of each centaur. When available, Col-OSSOS images were used to search also for comae.

Results. No cometary activity is detected in the OSSOS sample. We track the recent orbital evolution of each new centaur to confirm that none would actually be predicted to be active, and we provide size estimates for the objects.

Conclusions. The addition of 20 OSSOS objects to the population of ~250 known centaurs is consistent with the currently understood scenario, in which drastic drops in perihelion distance induce changes in the thermal balance prone to trigger cometary activity in the giant planet region.