The stellar population of the Lupus clouds

Hughes, Joanne; Hartigan, Patrick; Krautter, J.; Kelemen, J.

doi:10.1086/117135

Cited by 183 publications

(293 citation statements)

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“…This is consistent with the faintness of the central source, which is probably due to the obscuration by a circumstellar disk seen nearly edge-on (Hughes et al 1994), despite the lack of the pronounced dip in the mid-infrared spectral energy distribution near 8 μm (Chapman et al 2007) that is characteristic of a near edge-on viewing geometry (D'Alessio et al 1999). The basis of the jet has been studied in depth thanks to the high spatial resolution observations provided by STIS at the Hubble Space Telescope, which have allowed a detailed analysis of the physical conditions near the launching region both along and across the jet, as well as the identification of hints of rotation (Coffey et al 2004(Coffey et al , 2007 and an estimate of the mass-loss rate in the outflow, which is found to be a remarkably high ∼1.2 × 10 −8 M yr −1 (Coffey et al 2008).…”

Section: Th 28 and The Hh 228/hh 989 Jetsupporting

confidence: 85%

News on two jets in Lupus 3

Comerón¹,

Fernández

2011

A&A

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Context. Jets from solar-type and low-mass stars are typical manifestations of stellar youth. Shocks along these jets produce visible, generally fast-moving Herbig-Haro objects whose proper motions are easily measured in nearby star-forming regions using images taken just a few years apart. Herbig-Haro objects have now been observed in association with objects close to the substellar boundary. Aims. We present second-epoch observations of the central area of the Lupus 3 star-forming region that include two of its most interesting Herbig-Haro systems. One is HH 228, produced by the classical T Tauri star Th 28 (=Sz 102), whereas the other is HH 600, which has its origin in the very low-mass star Par-Lup3-4. Methods. Narrow-band imaging through filters centered on the Hα and the [SII] lines was obtained with the FORS2 instrument at the Very Large Telescope (VLT) in mid-2010. The images obtained were compared to others obtained in early 2003, leading to the discovery of HH 600. Results. New Herbig-Haro objects are found at large distances from Th 28 and to be associated with it, representing an extension of the HH 228 jet to a projected distance of 0.32 pc from Th 28. The farthest Herbig-Haro object is HH 989, whose possible relationship with Th 28 had been already suggested in a previous study but is now kinematically confirmed. We find other likely Herbig-Haro objects whose proper motions are less indicative of a connection with Th 28, but which may be caused by oblique shocks near the outer walls of its jet. For the HH 600 jet, the knot discovered by ourselves in 2003 to the southeast of Par-Lup3-4 is found to have clearly moved and faded. Using high resolution spectroscopy obtained in 2003 and the proper motion that we can measure now, we determine a spatial velocity of 170 ± 30 km s −1 . The northwestern jet is found to have grown in prominence in the intervening years. The possible relationship of other Herbig-Haro objects in the region with Th 28, Par-Lup3-4, and other young stellar objects in the area is discussed.

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Section: Th 28 and The Hh 228/hh 989 Jetsupporting

confidence: 85%

News on two jets in Lupus 3

Comerón¹,

Fernández

2011

A&A

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“…From this, we conclude that the star probably has an F-G spectral type. Figure 4 shows the Hughes et al 1994, for Taurus-Auriga TTS from the compilation in Neuhäuser et al 1995. ) location of LTS J054427-692659 in the HR diagram.…”

Section: Resultsmentioning

confidence: 99%

First spectroscopically confirmed discovery of an extragalactic T Tauri star

Wichmann

Schmitt

Krautter³

2001

A&A

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Abstract.We report the first spectroscopic discovery of an extragalactic bona-fide T Tauri star. The object, LTS J054427-692659, is a low-mass, late-type star located within the LMC dark cloud Hodge II 139. It shows Hα emission with an equivalent width of 78Å, in line with galactic T Tauri stars, but in excess of any main-sequence dwarf star. The only known plausible interpretation of LTS J054427-692659 is a LMC T Tauri star.

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“…TWA-30A may harbor a disk because its optical and infrared spectra show emission lines due to accretion activity (Looper et al 2010a). However, there is no infrared data to suggest whether TWA-30A shows excess emission at wavelengths Gauvin & Strom (1992); (8) Hughes et al (1994); (9) Weise et al (2010). shorter than 8 μm. Thus, we do not count this source when calculating the disk fraction in TW Hya.…”

Section: Appendix A: the Disk Frequencies In Star-formation Regionsmentioning

confidence: 99%

Young stars inϵChamaleontis and their disks: disk evolution in sparse associations

Fang

Boekel

Bouwman

et al. 2012

A&A

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Context. The nearby young stellar association 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 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 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 Cha. HD 104237C is the lowest mass member of Cha with an estimated mass of ∼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 μm 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 C 2 H 2 rovibrational band around 13.7 μm on the IRS spectrum of USNO-B120144.7. We find strong signatures of grain growth and crystallization in all Cha members with 10 μm features detected in their IRS spectra. We combine the dust properties derived in the Cha sample with those found using identical or similar methods in the MBM 12, Coronet, η 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 ∼10 −9 M yr −1 , possibly indicating that those disks are sufficiently turbulent to prevent grains of several microns in size to sink into the disk interior.

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The stellar population of the Lupus clouds

Cited by 183 publications

References 0 publications

News on two jets in Lupus 3

News on two jets in Lupus 3

First spectroscopically confirmed discovery of an extragalactic T Tauri star

Young stars inϵChamaleontis and their disks: disk evolution in sparse associations

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