Young stellar objects in Lynds 1641 disks, accretion, and star formation history. (2013)
Keywords :
accretion, accretion disks - protoplanetary disks - stars pre-main sequence
Abstract:We investigate the young stellar objects (YSOs) in the Lynds 1641 (L1641) cloud using multi-wavelength data including Spitzer, WISE, the Two Micron All Sky Survey, and XMM covering ~1390 YSOs across a range of evolutionary stages. In addition, we targeted a sub-sample of YSOs for optical spectroscopy with the MMT/Hectospec and the MMT/Hectochelle. We use these data, along with archival photometric data, to derive spectral types, extinction values, masses, ages, and accretion rates. We obtain a disk fraction of ~50% in L1641. The disk frequency is almost constant as a function of stellar mass with a slight peak at log (M_*_/M_{sun}_){approx}-0.25. The analysis of multi-epoch spectroscopic data indicates that the accretion
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We combine newly obtained spectroscopic data from Hectospec and
Hectochelle with photometric data from Paper I (Fang et al., 2009,
Cat. J/A+A/504/461).
The intermediate-resolution spectra of sources were taken with the
Hectospec multi-object spectrograph in the range 3700-9000{AA} with a
resolution of ~5{AA}. The observational data were taken on the nights
of 2011 January 23, 24, and 25.
The high-resolution H{alpha} spectroscopy of sources was obtained with
the Hectochelle multi-object spectrograph which can take a maximum of
240 spectra simultaneously with a spectral resolution of 34000. We
used the OB 26 filter which simultaneously covers H{alpha} emission
line and the Li I(6708) absorption line. The observational data were
taken on the night of 2010 February 5 with two pointings.
- II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
- II/311 : WISE All-Sky Data Release (Cutri+ 2012)
- V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
- II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
- J/ApJ/746/154 : Sco-Cen members spectroscopy (Pecaut+, 2012)
- J/A+A/533/A109 : Pisa pre-main sequence tracks and isochrones (Tognelli+, 2011)
- J/A+A/504/461 : Paper I. YSOs in L1630N and L1641 (Fang+, 2009)
- J/A+A/489/1409 : Infrared photometry and spectroscopy in L1641N (Galfalk+ 2008)
- J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)