Classical T Tauri stars with VPHAS+ – I. H α and<i>u</i>-band accretion rates in the Lagoon Nebula M8

Kalari, V.; Drew, J. E.; Barentsen, Geert; Drake, J. J.; Eislöffel, J.; Martín, E. L.; Parker, Quentin A.; Unruh, Y. C.; Walton, N. A.; Wright, N. J.

doi:10.1093/mnras/stv1676

Cited by 40 publications

(52 citation statements)

References 82 publications

(219 reference statements)

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“…The Hα photometry confirms that very few stars show Hα excess, usually used as sign of on-going accretion in pre-Main Sequence stars (e.g. Kalari et al 2015). This is in agreement with the fact that stars in the Vela OB2 region are older then 10 Myr and, hence, no accretion discs are expected (Fedele et al 2010 Sacco et al 2015), are listed in Tab.…”

Section: Properties Of the Clusterssupporting

confidence: 85%

A sextet of clusters in the Vela OB2 region revealed by Gaia

Beccari

Boffin

Jeřabková

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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Using Gaia DR2 data, combined with OmegaCAM ground-based optical photometry from the AD-HOC survey, and detailed Radial Velocity measurements from ESO-Gaia, we analyse in detail a 10×5 deg region around the Wolf-Rayet star γ 2 Vel, including the previously known clusters Gamma Vel and NGC2547. Using clustering analysis that considers positions, proper motions and parallax, we discover 6 clusters or associations -4 of which appear new. Analysis of the colour-magnitude diagram for these clusters show that 4 of them formed coevally from the same molecular clouds 10 Myr ago, while NGC 2547 formed together with a newly discovered cluster 30 Myr ago. This study shows the incredible wealth of data provided by Gaia for the study of young stellar clusters.

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Section: Properties Of the Clusterssupporting

confidence: 85%

A sextet of clusters in the Vela OB2 region revealed by Gaia

Beccari

Boffin

Jeřabková

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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“…Manara et al: X-Shooter study of accretion in Chamaeleon I 2014; Kalari et al 2015;Manara et al 2012. These values are in broad agreement with expectations from different theoretical models.…”

Section: Single Power-law Describing the Relation Of Accretion To Stesupporting

confidence: 67%

X-shooter study of accretion in Chamaeleon I

Manara

Testi

Herczeg

et al. 2017

A&A

172

242

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The dependence of the mass accretion rate on the stellar properties is a key constraint for star formation and disk evolution studies. Here we present a study of a sample of stars in the Chamaeleon I star-forming region carried out using spectra taken with the ESO VLT/X-Shooter spectrograph. The sample is nearly complete down to stellar masses (M ) ∼ 0.1M for the young stars still harboring a disk in this region. We derive the stellar and accretion parameters using a self-consistent method to fit the broadband flux-calibrated medium resolution spectrum. The correlation between accretion luminosity to stellar luminosity, and of mass accretion rate to stellar mass in the logarithmic plane yields slopes of 1.9±0.1 and 2.3±0.3, respectively. These slopes and the accretion rates are consistent with previous results in various star-forming regions and with different theoretical frameworks. However, we find that a broken powerlaw fit, with a steeper slope for stellar luminosity lower than ∼ 0.45 L and for stellar masses lower than ∼ 0.3 M is slightly preferred according to different statistical tests, but the single power-law model is not excluded. The steeper relation for lower mass stars can be interpreted as a faster evolution in the past for accretion in disks around these objects, or as different accretion regimes in different stellar mass ranges. Finally, we find two regions on the mass accretion versus stellar mass plane that are empty of objects: one region at high mass accretion rates and low stellar masses, which is related to the steeper dependence of the two parameters we derived. The second region is located just above the observational limits imposed by chromospheric emission, at M ∼ 0.3 − 0.4M . These are typical masses where photoevaporation is known to be effective. The mass accretion rates of this region are ∼ 10 −10 M /yr, which is compatible with the value expected for photoevaporation to rapidly dissipate the inner disk.

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“…We complement the spectroscopic and astrometric data with supporting literature data to aid the identification of young stars across the Lagoon Nebula. This includes membership probabilities for 2427 sources from the Massive Young starforming Complex Study in Infrared and X-rays (MYStIX, Feigelson et al 2013) presented by Broos et al (2013), and VST Photometric Hα Survey (VPHAS, Drew et al 2014) photometric Hα equivalent widths for 235 sources from Kalari et al (2015). Details of how these data were incorporated into our membership selection can be found in the next section.…”

Section: Supporting Datamentioning

confidence: 99%

“…The main sources of ionization are the massive stars 9 Sgr (HD 164794, an O4V(f) star) and the massive binary HD 165052 (O6.5V + O7.5V), as well as a number of late O and B-type stars (see e.g., Tothill et al 2008, and Figure 1). A rich population of relatively unreddened low-mass members has also been uncovered using optical and X-ray data (Sung et al 2000;Damiani et al 2004;Prisinzano et al 2005;Kalari et al 2015). The youngest stars in the region are associated with embedded populations in the Hourglass Nebula, which houses an ultra-compact Hii region, and the M8 E region around the massive protostar M8E-IR (Tothill et al 2008).…”

mentioning

confidence: 97%

The Gaia-ESO Survey: asymmetric expansion of the Lagoon Nebula cluster NGC 6530 from GES and Gaia DR2

Wright

Jeffries

Jackson

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The combination of precise radial velocities from multi-object spectroscopy and highly accurate proper motions from Gaia DR2 opens up the possibility for detailed 3D kinematic studies of young star forming regions and clusters. Here, we perform such an analysis by combining Gaia-ESO Survey spectroscopy with Gaia astrometry for ∼900 members of the Lagoon Nebula cluster, NGC 6530. We measure the 3D velocity dispersion of the region to be 5.35 +0.39 −0.34 km s −1 , which is large enough to suggest the region is gravitationally unbound. The velocity ellipsoid is anisotropic, implying that the region is not sufficiently dynamically evolved to achieve isotropy, though the central part of NGC 6530 does exhibit velocity isotropy that suggests sufficient mixing has occurred in this denser part. We find strong evidence that the stellar population is expanding, though this is preferentially occurring in the declination direction and there is very little evidence for expansion in the right ascension direction. This argues against a simple radial expansion pattern, as predicted by models of residual gas expulsion. We discuss these findings in the context of cluster formation, evolution and disruption theories.

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Classical T Tauri stars with VPHAS+ – I. H α andu-band accretion rates in the Lagoon Nebula M8

Cited by 40 publications

References 82 publications

A sextet of clusters in the Vela OB2 region revealed by Gaia

A sextet of clusters in the Vela OB2 region revealed by Gaia

X-shooter study of accretion in Chamaeleon I

The Gaia-ESO Survey: asymmetric expansion of the Lagoon Nebula cluster NGC 6530 from GES and Gaia DR2

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