Monitoring of the cometary activity of distant comet C/2006 S3 (LONEOS)^⋆

¹ University of Franche-Comté, Observatoire des Sciences de l’Univers THETA, Institut UTINAM - UMR CNRS 6213, BP 1615, 25010 Besançon Cedex, France
e-mail: rousselot@obs-besancon.fr
² Main Astronomical Observatory of NAS of Ukraine, 27 Akademika Zabolotnoho Street, 03680 Kyiv, Ukraine
³ Special Astrophysical Observatory of the Russian AS, 369167 Nizhnij Arkhyz, Russia
⁴ Center AMER Observatory of National Academy of Sciences of Ukraine, 27 Akademica Zabolotnoho Street, 03680 Kyiv, Ukraine
⁵ IC AMER Terskol Observatory, Terskol, 361605 Kabardino-Balkaria Republic, Russia

Received: 16 May 2014
Accepted: 28 July 2014

Abstract

Context. The study of small bodies that have a cometary activity at a large heliocentric distance (larger than 5 au) is important for a better understanding of the physical properties of comets and their origin. Such studies require long-term monitoring and a significant observational effort.

Aims. Our goal is to monitor the cometary activity and search for possible emission lines of C/2006 S3 (LONEOS), which is a distant comet that was discovered in 2006 and passed perihelion at 5.13 au in April 2012.

Methods. We performed different observing runs with telescopes, ranging from 2 m to 6 m both in imaging and spectroscopic modes in the optical range, between 2006 and 2014.

Results. The comet C/2006 S3 (LONEOS) was a very active object with Afρ ~ 4000 cm at its maximum of activity, corresponding to a dust production rate of 82 kg s^-1, considering a mean geometric albedo of 0.1 and grain outflow velocities in the range 2−22 m s^-1. It appeared to be more active after its perihelion than before and we did not manage to detect any emission lines. Upper limits for the main cometary species that have emission bands in the optical range are provided. Our dust environment modeling is in agreement with a collimated source of dust that appeared in 2013.