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Abstract: Context. More than ten Centaurs are now known to have cometary activity atlarge heliocentric distance i.e. $\simeq$ 5-13 AU. Among these objects,174P-Echeclus which showed cometary activity at 13 AU from the Sun, is a uniquecase, because of: i the amplitude of its outburst, ii the source ofcometary activity that appears distinct from Echeclus itself.Aims. This paper aims at investigating the physical conditions that have ledto this unusual outburst. The purpose is also to quantify this phenomenon andto provide observational constraints for its modeling.Methods. We use observations from different telescopes, performed before,during, and after the outburst. We performed the main observations on March 23and 30, 2006, with the 8.2-m ESO Very Large Telescope and FORS 1 instrument.They consist of visible images and spectra.Results. Our main results are: i a cometary source distinct from Echeclusitself that presents a brightness distribution compatible with a diffusesource; ii a total dust production rate Q dust equal to about 86 kg.s^-1 anda parameter Afrho equal to 10,000cm; iii no emission lines CN and C 2 canbe detected in the visible range; iv the upper limits for the CN and C 2production rates are about 3.8x10^25 and 10^26 molecules.s^-1 respectively; vwe detected no Echeclus- satellite before the outburst up to M R equal to about26; vi the upper limit for the object generating the coma is about 8 km indiameter; vii and we detected no cometary activity one year later, in March2007.

Autor: P. Rousselot

Fuente: https://arxiv.org/

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