The variability of the CoRoT target HD171834: gamma Dor pulsations and/or activity?

TL;DR

This study analyzes CoRoT and ground-based data of HD171834, revealing complex variability likely caused by both gamma Dor pulsations and stellar activity, challenging the idea of it being a pure pulsator.

Contribution

It provides a combined space and ground-based analysis showing that HD171834's variability involves both pulsations and activity, a novel insight into its nature.

Findings

Detection of low-amplitude frequencies between 0 and 5 c/d.

Dominance of a frequency near 0.96 c/d and its harmonics.

Stellar activity significantly influences the star's variability.

Abstract

We present the preliminary results of a frequency and line-profile analysis of the CoRoT gamma Dor candidate HD171834. The data consist of 149 days of CoRoT light curves and a ground-based dataset of more than 1400 high-resolution spectra, obtained with six different instruments. Low-amplitude frequencies between 0 and 5 c/d, dominated by a frequency near 0.96 c/d and several of its harmonics, are detected. These findings suggest that HD171834 is not a mere gamma Dor pulsator and that stellar activity plays an important role in its variable behaviour. Based on CoRoT space data and on ground-based observations with ESO Telescopes at the La Silla Observatory under the ESO Large Programmes ESO LP 178.D-0361 and ESO LP 182.D-0356 (FEROS/2.2m and HARPS/3.6m), and data collected with FOCES/2.2m at the Centro Astronomico Hispano Aleman at Calar Alto, SOPHIE/1.93m at Observatoire de Haute Provence, FIES/NOT at Observatorio del Roque de los Muchachos, and HERCULES/1.0m at Mount John University Observatory.