Protoplanetary disk evolution and stellar parameters of T Tauri binaries in Chamaeleon I

• Published in: Astronomy and astrophysics (Berlin) 2013-06, Vol.554, p.1-25
• Main Authors: Daemgen, S., Petr-Gotzens, M. G., Correia, S., Teixeira, P. S., Brandner, W., Kley, W., Zinnecker, H.
• Format: Article
• Language: English
• Subjects: Accretion disks; Astronomy; binaries: visual; Binary stars; circumstellar matter; Clusters; Cosmic dust; Protoplanets; Star formation; stars: formation; stars: late-type; Stellar evolution
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201321220

Aims. This study aims to determine the impact of stellar binary companions on the lifetime and evolution of circumstellar disks in the Chamaeleon I (Cha I) star-forming region by measuring the frequency and strength of accretion and circumstellar dust signatures around the individual components of T Tauri binary stars. Methods. We used high-angular resolution adaptive optics JHKsL′ -band photometry and 1.5–2.5 μm spectroscopy of 19 visual binary and 7 triple stars in Cha I – including one newly discovered tertiary component – with separations between ~25 and ~1000 AU. The data allowed us to infer stellar component masses and ages and, from the detection of near-infrared excess emission and the strength of Brackett-γ emission, the presence of ongoing accretion and hot circumstellar dust of the individual stellar components of each binary. Results. Of all the stellar components in close binaries with separations of 25–100 AU, 10+15-5% show signs of accretion. This is less than half of the accretor fraction found in wider binaries, which itself appears significantly reduced (~44%) compared with previous measurements of single stars in Cha I. Hot dust was found around 50+30-15% of the target components, a value that is indistinguishable from that of Cha I single stars. Only the closest binaries (