A kinematic study and membership analysis of the Lupus star-forming region

Galli, P. A. B.; Bertout, C.; Teixeira, R.; Ducourant, C.

doi:10.1051/0004-6361/201220704

Cited by 47 publications

(85 citation statements)

References 73 publications

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“…The star was found to be SB2 from CORAVEL spectra. Makarov (2007) classified it as a member of the Lupus association (age 5-27 Myr) with a kinematic distance of 89 pc, but the star is not included in the recent study of the Lupus star-forming region by Galli et al (2013). Kinematic parameters are consistent with β Pic, Cha-Near, CrA and Upper Sco.…”

Section: Hip 36948 = Hd 61005mentioning

confidence: 99%

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

Desidera

Covino

Messina

et al. 2015

A&A

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Context. Young, close stars are ideal targets for searching planets using the direct imaging technique. The determination of stellar parameters is crucial for the interpretation of imaging survey results, particularly since the luminosity of substellar objects has a strong dependence on system age. Aims. We have conducted a large program with NaCo at the VLT to search for planets and brown dwarfs in wide orbits around 86 stars. A large fraction of the targets observed with NaCo were poorly investigated in the literature. We performed a study to characterize the fundamental properties (age, distance, and mass) of the stars in our sample. To improve target age determinations, we compiled and analyzed a complete set of age diagnostics. Methods. We measured spectroscopic parameters and age diagnostics using dedicated observations acquired with FEROS and CORALIE spectrographs at La Silla Observatory. We also made extensive use of archival spectroscopic data and the results that are available in the literature. Additionally, we exploited photometric time-series, which are available in ASAS and Super-WASP archives, to derive a rotational period for a large fraction of our program stars. Results. We provided updated characterization of all the targets observed in the VLT NaCo Large program, a survey designed to probe the occurrence of exoplanets and brown dwarfs in wide orbits. The median distance and age of our program stars are 64 pc and 100 Myr, respectively. Nearly all the stars have masses between 0.70 and 1.50 M , with a median value of 1.01 M . The typical metallicity is close to solar with a dispersion that is smaller than that of samples usually observed in radial velocity surveys. Several stars are confirmed or proposed here to be members of close young moving groups. Eight spectroscopic binaries are identified.

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Section: Hip 36948 = Hd 61005mentioning

confidence: 99%

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

Desidera

Covino

Messina

et al. 2015

A&A

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“…Both the Lupus and Taurus-Auriga associations discussed in this paper have been identified by using the convergent point search method applied to proper motion data in our previous studies (Bertout & Genova 2006;Galli et al 2013) and the physical properties of the comoving stars were computed in the same completeness limits as described in Sect. 2.…”

Section: Comparison With the Taurus-auriga Associationmentioning

confidence: 99%

Evolution of the T Tauri star population in the Lupus association

Galli

Bertout

Teixeira

et al. 2015

A&A

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Aims. In a recent study, we derived individual distances for 109 pre-main sequence stars that define the Lupus kinematic association of young stars. Here, we use these new distances to derive the masses and ages of Lupus T Tauri stars with the aim of better constraining the lifetime of their circumstellar disks. Methods. Using the photometric and spectroscopic information available in the literature, we computed the photospheric luminosity of 92 T Tauri stars in the Lupus association. Then, we estimated their masses and ages from theoretical evolutionary models. Based on Monte Carlo simulations and statistical tests, we compare the mass and age distribution of the classical T Tauri stars (CTTS) and weak-line T Tauri (WTTS) in our sample. Results. We show that the CTTSs are on average younger than the WTTSs and that the probability that both T Tauri subclasses are drawn from the same mass and age parental distribution is very low. Our results favor the scenario proposed earlier for the TaurusAuriga association, where the CTTSs evolve into WTTSs when their disks are fully accreted by the star. Based on an empirical disk model, we find that the average disk lifetime for the T Tauri stars in the Lupus association is τ d = 3 × 10 6 (M * /M ) 0.55 yr. Conclusions. We find evidence that the average lifetime of the circumstellar disks in the Lupus association is shorter than in the Taurus-Auriga association and discuss the implications of this result.

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“…The derived disk luminosity, inferred from the spectral energy distribution (SED) integrated excess above the stellar photosphere, is ∼0.13 L (Mortier et al 2011;Merín et al 2008). We adopt the recent value of d = 185 +11 −10 pc derived by Galli et al (2013) for the Lupus 3 cloud, with an improved convergent point search method, for the distance to the source.…”

Section: Introductionmentioning

confidence: 99%

ALMA observations of the Th 28 protostellar disk

Louvet

Dougados

Cabrit

et al. 2016

A&A

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Aims. Recently, differences in Doppler shifts across the base of four close classical T Tauri star jets have been detected with the HST in optical and near-ultraviolet (NUV) emission lines, and these Doppler shifts were interpreted as rotation signatures under the assumption of steady state flow. To support this interpretation, it is necessary that the underlying disks rotate in the same sense. Agreement between disk rotation and jet rotation determined from optical lines has been verified in two cases and rejected in one case. Meanwhile, the near-ultraviolet lines, which may trace faster and more collimated inner spines of the jet than optical lines, either agree or show no clear indication. We propose to perform this test on the fourth system, Th 28. Methods. We present ALMA high angular resolution Band 7 continuum, 12 CO(3−2) and 13 CO(2−1) observations of the circumstellar disk around the T Tauri star Th 28. Results. The sub-arcsecond angular resolution (0.46 × 0.37 ) and high sensitivity reached enable us to detect, in CO and continuum, clear signatures of a disk in Keplerian rotation around Th 28. The 12 CO emission is clearly resolved, allowing us to derive estimates of disk position angle and inclination. The large velocity separation of the peaks in 12 CO, combined with the resolved extent of the emission, indicate a central stellar mass in the range 1−2 M . The rotation sense of the disk is well detected in both 13 CO and 12 CO emission lines, and this direction is opposite to that implied by the transverse Doppler shifts measured in the optical lines of the jet. Conclusions. The Th 28 system is now the second system, among the four investigated so far, where counter-rotation between the disk and the optical jet is detected. These findings imply either that optical transverse velocity gradients detected with HST do not trace jet rotation or that modeling the flow with the steady assumption is not valid. In both cases jet rotation studies that rely solely on optical lines are not suitable to derive the launching radius of the jet.

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A kinematic study and membership analysis of the Lupus star-forming region

Cited by 47 publications

References 73 publications

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

Evolution of the T Tauri star population in the Lupus association

ALMA observations of the Th 28 protostellar disk

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