PMO OpenIR  > 分子云与恒星形成研究团组
Young stars in epsilon Chamaleontis and their disks: disk evolution in sparse associations
Fang, M. ; van Boekel, R. ; Bouwman, J. ; Henning, Th. ; Lawson, W. A. ; Sicilia-Aguilar, A.
Corresponding Author房敏
AbstractContext. The nearby young stellar association epsilon Cha has an estimated age of 3-5 Myr, making it an ideal laboratory to study the disk dissipation process and provide empirical constraints on the timescale of planet formation.Aims. We wish to complement existing optical and near-infrared data of the epsilon Cha association, which provide the stellar properties of its members, with mid-infrared data that probe the presence, geometry, and mineralogical composition of protoplanetary disks around individual stars.Methods. We combine the available literature data with our Spitzer/IRS spectroscopy and VLT/VISIR imaging data. We use proper motions to refine the membership of epsilon Cha. Masses and ages of individual stars are estimated by fitting model atmospheres to the optical and near-infrared photometry, followed by placement in the Hertzsprung-Russell diagram. The Spitzer/IRS spectra are analyzed using the two-layer temperature distribution spectral decomposition method.Results. Two stars previously identified as members, CXOU J120152.8 and 2MASS J12074597, have proper motions that are very different from those of the other stars. But other observations suggest that the two stars are still young and thus might still be related to epsilon Cha. HD104237C is the lowest mass member of epsilon Cha with an estimated mass of similar to 13-15 Jupiter masses. The very low mass stars USNO-B120144.7 and 2MASS J12005517 show globally depleted spectral energy distributions, pointing at strong dust settling. 2MASS J12014343 may have a disk with a very specific inclination, where the central star is effectively screened by the cold outer parts of a flared disk, but the 10 mu m radiation of the warm inner disk can still reach us. We find that the disks in sparse stellar associations are dissipated more slowly than those in denser (cluster) environments. We detect C2H2 rovibrational band around 13.7 mu m on the IRS spectrum of USNO-B120144.7. We find strong signatures of grain growth and crystallization in all epsilon Cha members with 10 mu m features detected in their IRS spectra. We combine the dust properties derived in the epsilon Cha sample with those found using identical or similar methods in the MBM12, Coronet, eta Cha associations, and in the cores-to-disks legacy program. We find that disks around low-mass young stars show a negative radial gradient in the mass-averaged grain size and mass fraction of crystalline silicates. A positive correlation exists between the mass-averaged grain sizes of amorphous silicates and the accretion rates if the latter is above similar to 10(-9) M-circle dot yr(-1), possibly indicating that those disks are sufficiently turbulent to prevent grains of several microns in size to sink into the disk interior.
Subject AreaAstronomy & Astrophysics
Document Type期刊论文
Recommended Citation
GB/T 7714
Fang, M.,van Boekel, R.,Bouwman, J.,et al. Young stars in epsilon Chamaleontis and their disks: disk evolution in sparse associations[J]. ASTRONOMY & ASTROPHYSICS,2013,549:A15-A15.
APA Fang, M.,van Boekel, R.,Bouwman, J.,Henning, Th.,Lawson, W. A.,&Sicilia-Aguilar, A..(2013).Young stars in epsilon Chamaleontis and their disks: disk evolution in sparse associations.ASTRONOMY & ASTROPHYSICS,549,A15-A15.
MLA Fang, M.,et al."Young stars in epsilon Chamaleontis and their disks: disk evolution in sparse associations".ASTRONOMY & ASTROPHYSICS 549(2013):A15-A15.
Files in This Item:
File Name/Size DocType Version Access License
2013060Young stars i(1123KB) 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[Fang, M.]'s Articles
[van Boekel, R.]'s Articles
[Bouwman, J.]'s Articles
Baidu academic
Similar articles in Baidu academic
[Fang, M.]'s Articles
[van Boekel, R.]'s Articles
[Bouwman, J.]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[Fang, M.]'s Articles
[van Boekel, R.]'s Articles
[Bouwman, J.]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 2013060Young stars in epsilon Chamaleontis and their disks.pdf
Format: Adobe PDF
This file does not support browsing at this time
All comments (0)
No comment.

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.