New “weak-line"–T Tauri stars in Lupus

Krautter, J.; Wichmann, R.; Schmitt, J. H. M. M.; Alcalá, J. M.; Neuhäuser, R.; Terranegra, L.

doi:10.1051/aas:1997163

Cited by 114 publications

(121 citation statements)

References 16 publications

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“…Ophiuchus contains one of the nearest, best studied regions of star formation ; Lupus, like Taurus, appears to be forming only stars of low to intermediate mass, including more than 100 T Tauri stars recently discovered by Krautter et al (1997). Both clouds lie at similar distances (D150 pc) and have similar masses (D104 de Geus (1992) has shown that both lie near M _ ) ; the edge of an expanding H I shell surrounding the Upper Scorpius subgroup of the Sco-Cen OB association.…”

Section: First Quadrantmentioning

confidence: 99%

The Milky Way in Molecular Clouds: A New Complete CO Survey

Dame

Hartmann

Thaddeus

2001

ApJ

2,146

178

2,713

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New large-scale CO surveys of the Ðrst and second Galactic quadrants and the nearby molecular cloud complexes in Orion and Taurus, obtained with the CfA 1.2 m telescope, have been combined with 31 other surveys obtained over the past two decades with that instrument and a similar telescope on Cerro Tololo in Chile, to produce a new composite CO survey of the entire Milky Way. The survey consists of 488,000 spectra that Nyquist or beamwidth sample the entire Galactic plane over a (1 8 ¡) strip 4¡È10¡ wide in latitude, and beamwidth or sample nearly all large local clouds at higher lati-1 4 ¡ tudes. Compared with the previous composite CO survey of Dame et al. (1987), the new survey has 16 times more spectra, up to 3.4 times higher angular resolution, and up to 10 times higher sensitivity per unit solid angle. Each of the component surveys was integrated individually using clipping or moment masking to produce composite spatial and longitude-velocity maps of the Galaxy that display nearly all of the statistically signiÐcant emission in each survey but little noise.The composite maps provide detailed information on individual molecular clouds, suggest relationships between clouds and regions widely separated on the sky, and clearly display the main structural features of the molecular Galaxy. In addition, since the gas, dust, and Population I objects associated with molecular clouds contribute to the Galactic emission in every major wavelength band, the precise kinematic information provided by the present survey will form the foundation for many large-scale Galactic studies.A map of molecular column density predicted from complete and unbiased far-infrared and 21 cm surveys of the Galaxy was used both to determine the completeness of the present survey and to extrapolate it to the entire sky at o b o \ 32¡. The close agreement of the observed and predicted maps implies that only D2% of the total CO emission at o b o \ 32¡ lies outside our current sampling, mainly in the regions of Chamaeleon and the Gum Nebula. Taking into account this small amount of unobserved emission, the mean molecular column density decreases from D3 ] 1020 cm~2 at o b o \ 5¡ to D0.1 ] 1020 cm~2 at o b o \ 30¡ ; this drop is D6 times steeper than would be expected from a planeparallel layer, but is consistent with recent measurements of the mean molecular column density at higher latitudes.The ratio of the predicted molecular column density map to the observed CO intensity map provides a calibration of the mass conversion factor Out of the Galactic plane, X shows little systematic variation with latitude from a mean value of (1.8^0.3) ] 1020 cm~2 K~1 km~1 s. Given the large sky area and large quantity of CO data analyzed, we conclude that this is the most reliable measurement to date of the mean X value in the solar neighborhood.

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Section: First Quadrantmentioning

confidence: 99%

The Milky Way in Molecular Clouds: A New Complete CO Survey

Dame

Hartmann

Thaddeus

2001

ApJ

2,146

178

2,713

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“…Makarov (2007) linked the object kinematically to the Lupus association at a distance of approximately 185 pc. Henize (1976) and Krautter et al (1997) classified RXJ1615.3-3255 as a weakline T Tauri star, whereas Merín et al (2010) classified it as a potential transitional disc based on Spitzer spectra. resolved the disc at 880 µm with SMA observations and found that the emission from the disc is highly extended suggesting a large disc extending out to 115 au, and they measure a particularly low-density cavity extending to 30 au.…”

Section: Rxj16153-3255mentioning

confidence: 99%

Sparse aperture masking interferometry survey of transitional discs

Willson

Kraus

Kluska

et al. 2016

A&A

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Context. Transitional discs are a class of circumstellar discs around young stars with extensive clearing of dusty material within their inner regions on 10s of au scales. One of the primary candidates for this kind of clearing is the formation of planet(s) within the disc that then accrete or clear their immediate area as they migrate through the disc. Aims. The goal of this survey was to search for asymmetries in the brightness distribution around a selection of transitional disc targets. We then aimed to determine whether these asymmetries trace dynamically-induced structures in the disc or the gap-opening planets themselves. Methods. Our sample included eight transitional discs. Using the Keck/NIRC2 instrument we utilised the Sparse Aperture Masking (SAM) interferometry technique to search for asymmetries indicative of ongoing planet formation. We searched for close-in companions using both model fitting and interferometric image reconstruction techniques. Using simulated data, we derived diagnostics that helped us to distinguish between point sources and extended asymmetric disc emission. In addition, we investigated the degeneracy between the contrast and separation that appear for marginally resolved companions. Results. We found FP Tau to contain a previously unseen disc wall, and DM Tau, LkHα330, and TW Hya to contain an asymmetric signal indicative of point source-like emission. We placed upper limits on the contrast of a companion in RXJ1842.9-3532 and V2246 Oph. We ruled the asymmetry signal in RXJ1615.3-3255 and V2062 Oph to be false positives. In the cases where our data indicated a potential companion we computed estimates for the value of M cṀc and found values in the range of 10 −5 − 10 −3 M 2 J yr −1 . Conclusions. We found significant asymmetries in four targets. Of these, three were consistent with companions. We resolved a previously unseen gap in the disc of FP Tau extending inwards from approximately 10 au.

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“…ROSAT pre-main sequence stars in the area of the Lupus clouds Krautter et al (1997) report the discovery by the ROSAT X-ray satellite of an extended population of weak-lined T Tauri stars (WTTS) towards the Lupus clouds, which far exceeds in number the CTTS population coincident with the cloud cores. Some of these WTTS are seen projected onto regions of high obscuration, The thick solid and dashed lines are the 1 and 10 Myr isochrones, respectively, from the models by Baraffe et al (1998).…”

Section: Comparison To Other Populationsmentioning

confidence: 99%

“…Wichmann et al (1997b) argue that the age (up to 5−6 × 10 7 yr) and spatial distribution of the ROSAT stars are consistent with their belonging to the Gould Belt rather than to the Lupus clouds themselves, whose mean age is estimated to be around 5 Myr. The UCAC3 catalogue contains counterparts for 91 of the 136 ROSAT stars from Krautter et al (1997). These sources are, with a few exceptions, located in the same area as Group A in the vector-point diagram of Fig.…”

Section: Comparison To Other Populationsmentioning

confidence: 99%

A proper motion study of the Lupus clouds using Virtual Observatory tools

Martí

Jiménez-Esteban

Solano

2011

A&A

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Context. The Lupus dark cloud complex is a well-known, nearby low-mass star-forming region, probably associated with the Gould Belt. In recent years, the number of stellar and substellar Lupus candidate members has been remarkably increased thanks to the Cores to Disks (c2d) Spitzer Legacy Program and other studies. However, most of these newly discovered objects still lack confirmation that they belong to the dark clouds. Aims. By using available kinematical information, we test the membership of the new Lupus candidate members proposed by the c2d program and by a complementary optical survey. We also investigate the relationship between the proper motions and other properties of the objects, in order to get some clues about their formation and early evolution. Methods. We compiled a list of members and possible members of Lupus 1, 3, and 4, together with all available information on their spectral types, disks, and physical parameters. Using Virtual Observatory tools, we cross-matched this list with the available astrometric catalogues to get proper motions for our objects. Our final sample contains sources with magnitudes I < 16 mag and estimated masses 0.1 M . Results. According to the kinematic information, our sources can be divided into two main groups. The first one contains sources with higher proper motions in agreement with other Gould Belt populations and with spatial distribution, optical and near-infrared colours, and disk composition consistent with these objects belonging to the Lupus clouds. In the second group, sources have lower proper motions with random orientations, and they are mostly located outside the cloud cores, making their association with the Lupus complex more doubtful. We investigate the properties of the higher proper motion group, but cannot find any correlations with spatial location, binarity, the presence of a circumstellar disk, or with physical properties such as effective temperature, luminosity, mass, or age. Conclusions. We conclude that the lower proper motion group probably represents a background population or mixture of populations unrelated to the Lupus clouds. The higher proper motion group, on the other hand, has properties consistent with it being a genuine population of the Lupus star-forming region. More accurate proper motions and/or radial velocity information are required for a more detailed study of the kinematic properties of the Lupus stellar members.

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New “weak-line"–T Tauri stars in Lupus

Cited by 114 publications

References 16 publications

The Milky Way in Molecular Clouds: A New Complete CO Survey

The Milky Way in Molecular Clouds: A New Complete CO Survey

Sparse aperture masking interferometry survey of transitional discs

A proper motion study of the Lupus clouds using Virtual Observatory tools

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