Evolution of the T Tauri star population in the Lupus association

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

doi:10.1051/0004-6361/201525804

Cited by 35 publications

(25 citation statements)

References 55 publications

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“…Hughes et al (1994) concluded that Lupus may be a region of sub-critical star formation where magnetic fields slow the collapse of the clouds, leading to low mass accretion rates with the consequence that the lowest mass stars in Lupus are less active than similar objects in other regions. On the other hand, Galli et al (2015) provided evidence that the disc lifetimes may be shorter in Lupus in comparison with those in Taurus. A crucial aspect of the models regarding viscously evolving discs is the presence of the correlations of M disc with M andṀ acc (e.g. Lynden-Bell & Pringle 1974;Hartmann et al 2006;Dullemond et al 2006;Tilling et al 2008, and references therein).…”

Section: Discussionmentioning

confidence: 96%

X-shooter spectroscopy of young stellar objects in Lupus

Alcalá

Manara

Natta

et al. 2017

A&A

402

698

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The mass accretion rate,Ṁ acc , is a key quantity for the understanding of the physical processes governing the evolution of accretion discs around young low-mass (M 2.0M ) stars and substellar objects (YSOs). We present here the results of a study of the stellar and accretion properties of the (almost) complete sample of class II and transitional YSOs in the Lupus I, II, III and IV clouds, based on spectroscopic data acquired with the VLT/X-Shooter spectrograph. Our study combines the dataset from our previous work with new observations of 55 additional objects. We have investigated 92 YSO candidates in total, 11 of which have been definitely identified with giant stars unrelated to Lupus. The stellar and accretion properties of the 81 bona fide YSOs, which represent more than 90% of the whole class II and transition disc YSO population in the aforementioned Lupus clouds, have been homogeneously and self-consistently derived, allowing for an unbiased study of accretion and its relationship with stellar parameters. The accretion luminosity, L acc , increases with the stellar luminosity, L , with an overall slope of ∼1.6, similar but with a smaller scatter than in previous studies. There is a significant lack of strong accretors below L ≈0.1L , where L acc is always lower than 0.01 L . We argue that the L acc -L slope is not due to observational biases, but is a true property of the Lupus YSOs. The logṀ acclogM correlation shows a statistically significant evidence of a break, with a steeper relation for M 0.2 M and a flatter slope for higher masses. The bimodality of theṀ acc -M relation is confirmed with four different evolutionary models used to derive the stellar mass. The bimodal behaviour of the observed relationship supports the importance of modelling self-gravity in the early evolution of the more massive discs, but other processes, such as photo-evaporation and planet formation during the YSO's lifetime, may also lead to disc dispersal on different timescales depending on the stellar mass. The sample studied here more than doubles the number of YSOs with homogeneously and simultaneously determined L acc and luminosity, L line , of many permitted emission lines. Hence, we also refined the empirical relationships between L acc and L line on a more solid statistical basis.

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Section: Discussionmentioning

confidence: 96%

X-shooter spectroscopy of young stellar objects in Lupus

Alcalá

Manara

Natta

et al. 2017

A&A

402

698

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“…Figure 16. [OI] line profiles and velocity components for "SCJ" objects, ordered by the HVC EWtot,corr to visualize the correlations shown in Figure 6. Stellar masses are taken from Herczeg & Hillenbrand (2014) for Taurus sources and from the compilation in Salyk et al (2013) for sources in other regions, apart from AS353A (Rigliaco et al 2015), DFTau (Allen et al 2017), EXLup (Galli et al 2015), RXJ1615 (Andrews et al 2011), RYLup (Alcalá et al 2017), and V853Oph (Sartori et al 2003). Figure 17. [OI] line profiles and velocity components for objects with no detection or only HVC.…”

Section: Sc-type Lvcmentioning

confidence: 99%

Kinematic Links and the Coevolution of MHD Winds, Jets, and Inner Disks from a High-resolution Optical [ ] Survey

Banzatti

Pascucci

Edwards

et al. 2019

ApJ

120

236

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We present a survey of optical [OI] emission at 6300Å toward 65 T Tauri stars at the spectral resolution of ∼7 km/s. Past work identified a highly blueshifted velocity component (HVC) tracing microjets, and a less blueshifted low-velocity-component (LVC) attributed to winds. We focus here on the LVC kinematics to investigate links between winds, jets, accretion, and disk dispersal. We track the behavior of four types of LVC components: a broad and narrow component ("BC" and "NC") in LVCs that are decomposed into two Gaussians, which typically have an HVC, and the single-Gaussian LVC profiles separated into those that have an HVC ("SCJ") and those that do not ("SC"). LVC centroid velocities and line widths correlate with HVC equivalent width and accretion luminosity, suggesting that LVC/winds and HVC/jets are kinematically linked and connected to accretion. The deprojected HVC velocity correlates with accretion luminosity, showing that faster jets come with higher accretion. BC and NC kinematics correlate and their blueshifts are maximum at ∼ 35 • , suggesting a conical wind geometry with this semi-opening angle. Only SCs include n 13−31 up to ∼ 3 and their properties correlate with this infrared index, showing that [OI] emission recedes to larger radii as the inner dust is depleted, tracing less dense/hot gas and a decrease in wind velocity. All together, these findings support a scenario where optically thick, accreting inner disks launch radially-extended MHD disk winds that feed jets, and where inner disk winds recede to larger radii and jets disappear in concert with dust depletion.

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“…Finally, it is also possible that the YSO population of Lupus is different from the populations in other regions. For example, Galli et al (2015) have found that the lifetimes of disks may be shorter in this region than the lifetimes for objects located in the Taurus star-forming region. Although this result relies on individual age estimates, it suggests that objects located in different environments might follow different evolutionary paths.…”

Section: Constraints On Accretion and Disk Evolution Theoriesmentioning

confidence: 99%

X-Shooter study of accretion in Chamaeleon I

Manara

Fedele

Herczeg

et al. 2016

A&A

125

163

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We present the analysis of 34 new VLT/X-Shooter spectra of young stellar objects in the Chamaeleon I star-forming region, together with four more spectra of stars in Taurus and two in Chamaeleon II. The broad wavelength coverage and accurate flux calibration of our spectra allow us to estimate stellar and accretion parameters for our targets by fitting the photospheric and accretion continuum emission from the Balmer continuum down to ∼700 nm. The dependence of accretion on stellar properties for this sample is consistent with previous results from the literature. The accretion rates for transitional disks are consistent with those of full disks in the same region. The spread of mass accretion rates at any given stellar mass is found to be smaller than in many studies, but is larger than that derived in the Lupus clouds using similar data and techniques. Differences in the stellar mass range and in the environmental conditions between our sample and that of Lupus may account for the discrepancy in scatter between Chamaeleon I and Lupus. Complete samples in Chamaeleon I and Lupus are needed to determine whether the difference in scatter of accretion rates and the lack of evolutionary trends are not influenced by sample selection.

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Evolution of the T Tauri star population in the Lupus association

Cited by 35 publications

References 55 publications

X-shooter spectroscopy of young stellar objects in Lupus

X-shooter spectroscopy of young stellar objects in Lupus

Kinematic Links and the Coevolution of MHD Winds, Jets, and Inner Disks from a High-resolution Optical [ ] Survey

X-Shooter study of accretion in Chamaeleon I

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