A Targeted Search for Main Belt Comets

TL;DR

This study conducted a targeted search for Main Belt Comets by observing 534 asteroids near perihelion, identifying potential activity in one object, and supporting the idea of dynamical clustering of MBCs in the asteroid belt.

Contribution

It presents a new targeted observational approach focusing on objects with specific orbital clustering to find MBCs, increasing detection efficiency compared to previous surveys.

Findings

Detected a potential MBC candidate with a faint tail.

Estimated a higher detection rate (~1:300) than previous surveys.

Results support the clustering hypothesis of MBCs in the asteroid belt.

Abstract

Main Belt Comets (MBCs) exhibit sublimation-driven activity while occupying asteroid-like orbits in the Main Asteroid Belt. MBCs and candidates show stronger clustering of their longitudes of perihelion around 15{\deg} than other objects from the Outer Main Belt (OMB). This potential property of MBCs could facilitate the discovery of new candidates by observing objects in similar orbits. We acquired deep r-band images of 534 targeted asteroids using the INT/WFC between 2018 and 2020. Our sample is comprised of OMB objects observed near perihelion, with longitudes of perihelion between 0{\deg} and 30{\deg} and orbital parameters similar to knowns MBCs. Our pipeline applied activity detection methods to 319 of these objects to look for tails or comae, and we visually inspected the remaining asteroids. Our activity detection pipeline highlighted a faint anti-solar tail-like feature around 2001 NL19 (279870) observed on 2018 November 07, six months after perihelion. This is consistent with cometary activity but additional observations of this object will be needed during its next perihelion to investigate its potential MBC status. If it is active our survey yields a detection rate of $\sim$1:300, which is higher than previous similar surveys, supporting the idea of dynamical clustering of MBCs. If not, it is consistent with previously estimated abundance rates of MBCs in the OMB (<1:500).