Rotational and Candidate-Eclipsing-Binary Light Curves for Pre-Main-Sequence Stars in the Chamaeleon I Star-Forming Cloud

Publications of the Astronomical Society of Australia

Warrick A. Lawson¹ 

[1] Lisa A. Crause

关键词: open clusters and associations: individual (Chamaeleon I);    stars: individual (CHXR 3;    CHXR 20;    CHXR 33;    CHXR 37;    CHXR 40;    CHXR 47;    CHXR 53;    CHXR 59;    CHXR 71;    CHXR 85);    stars: pre-main sequence;    stars: rotation;    stars: spots;    binaries: eclipsing;   

DOI  :  10.1071/AS08018

学科分类：天文学(综合)

来源: CSIRO

【 摘 要 】

We present the results of a photometric survey for variability in ten X-ray-emitting low-mass stars in the Chamaeleon region. Eight of the stars we observed are bona fide pre-main-sequence members of the ∼2 Myr-old Chamaeleon I star-forming cloud. The other two stars are young with high levels of relative X-ray emission, but with discordant proper motions they are probable non-members of the cloud. In six of the stars we monitored, periodic variations on timescales of 2.5–11.5 d were detected, that we ascribe to stellar rotation and the presence of cool starspots. Two other stars, CHXR 20 and CHXR 85, show large amplitude variations at visual and near-infrared wavelengths and are candidate eclipsing binaries. Compared to the rotational properties of low-mass stars in the ≈8 Myr-old η Chamaeleontis cluster, we find that the older η Chamaeleontis stars have several times higher surface specific angular momentum than the younger Chamaeleon I stars. The apparent increase in angular momentum between ∼2 and 8 Myr might be due to changes in stellar internal structure as the stars evolve, or evidence for a different rotational history between members of the two star-forming regions.

【 授权许可】

Unknown