Observations of the 18-cm OH lines of comet 103P/Hartley 2 at Nan\c{c}ay in support to the EPOXI and Herschel missions

TL;DR

This study reports radio observations of OH lines in comet 103P/Hartley 2, providing insights into its water production and gas dynamics during its 2010 perihelion, supporting space missions like EPOXI and Herschel.

Contribution

It offers new measurements of water production rates and gas expansion velocity of the comet during its 2010 perihelion, aiding understanding of cometary activity.

Findings

Gas expansion velocity estimated at 0.83 km/s

Water production peaked at 1.9 x 10^{28} s^{-1}

OH lines detected over several months

Abstract

The 18-cm radio lines of the OH radical were observed in comet 103P/Hartley 2 with the Nan\c{c}ay radio telescope in support to its flyby by the EPOXI mission and to observations with the Herschel Space Observatory. The OH lines were detected from 24 September to 15 December 2010. These observations are used to estimate the gas expansion velocity within the coma to 0.83 \pm 0.08 km/s in October 2010. The water production increased steeply but progressively before perihelion, and reached 1.9 \pm 0.3 X 10E28 s-1 just before the EPOXI flyby.