Nucleus of active asteroid 358P/Pan-STARRS (P/2012 T1)

TL;DR

This study investigates the role of fast rotation in the active asteroid 358P by deep imaging and photometry, finding no evidence of fragments or debris related to rapid spin, and providing insights into its physical properties.

Contribution

It offers the first detailed rotational analysis of 358P, combining deep imaging and photometry to assess the influence of rotation on activity.

Findings

No fragments or debris detected larger than 8 mm.

The nucleus has an estimated diameter of 530 meters.

The 10-hour light curve shows no clear periodicity.

Abstract

The dust emission from active asteroids is likely driven by collisions, fast rotation, sublimation of embedded ice, and combinations of these. Characterising these processes leads to a better understanding of their respective influence on the evolution of the asteroid population. We study the role of fast rotation in the active asteroid 358P (P 2012/T1). We obtained two nights of deep imaging of 358P with SOAR/Goodman and VLT/FORS2. We derived the rotational light curve from time-resolved photometry and searched for large fragments and debris > 8 mm in a stacked, ultra-deep image. The nucleus has an absolute magnitude of m_R=19.68, corresponding to a diameter of 530 m for standard assumptions on the albedo and phase function of a C-type asteroid. We do not detect fragments or debris that would require fast rotation to reduce surface gravity to facilitate their escape. The 10-hour light curve does not show an unambiguous periodicity.