A Census of the Low Accretors. I: The Catalog

Abstract

Observations have shown that the disk frequency and the fraction of accreting pre-main-sequence stars decrease with the age of the population and that some stars appear to have disks while their accretion has stopped. Still, it is unclear how disk-bearing stars stop their accretion. To provide insight into the last stages of accretion in low-mass young stars, we conducted a survey of disk-bearing stars that are thought to be non-accretors to identify stars still accreting at very low rates. Here we present the first catalog of the survey of 170 disk-bearing non-accreting stars in Chamaeleon I, Orion OB1, Upper Scorpius, $\gamma$ Velorum, and Upper Centaurus Lupus, using He I $\lambda$10830 as a sensitive probe of accretion. We classify the line profiles into six types and argue that those showing redshifted and/or blueshifted absorption are still accreting. Using these classifications, we found that, among disk-bearing stars previously classified as non-accretors, at least 20-30% are still accreting, with a larger fraction of those at younger population ages. While the difference between the outer disk signature and accretion status is unclear, we find a difference between the inner disk excess and accretion status. There is no preference in the mass of the newly identified accretors, suggesting that the processes inhibiting accretion do not directly depend on mass in the typical mass range of T Tauri stars. Lastly, we found that at a low accretion level, the H$\alpha$ width at the 10% height criteria mischaracterizes a larger fraction of accretors than the line's equivalent width.

Published in AJ. Data tables are available on the Journal's website

References in corpus (20)

• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The unWISE Catalog: Two Billion Infrared Sources from Five Years of WISE Imaging
• A Spitzer view of protoplanetary disks in the gamma Velorum cluster
• Probing T Tauri Accretion and Outflow with 1 Micron Spectroscopy
• The Disk Population of the Chamaeleon I Star-Forming Region
• Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability
• Close companions around young stars
• The Gaia-ESO Survey: Chromospheric Emission, Accretion Properties, and Rotation in $\gamma$ Velorum and Chamaeleon I
• Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars
• An extensive VLT/X-Shooter library of photospheric templates of pre-main sequence stars
• Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates
• Peter Pan Disks: Long-lived Accretion Disks Around Young M Stars
• Active cool stars and He I 10830 Å: the coronal connection
• A spectroscopic census in young stellar regions: the Sigma Orionis cluster
• The Effect of Binarity on Circumstellar Disk Evolution
• The Evolution Of The Inner Regions of Protoplanetary Disks
• A survey for planetary-mass brown dwarfs in the Chamaeleon I star-forming region
• Investigating the rotational evolution of young, low mass stars using Monte Carlo simulations
• Accretion and outflow activity on the late phases of pre-main-sequence evolution. The case of RZ Piscium
• Modulated accretion in T Tauri star RY Tau -- stable MHD propeller or a planet at 0.2 AU?

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• The distribution of accretion rates as a diagnostic of protoplanetary disc evolution
• A Census of the Low Accretors. II: Accretion Properties
• The He I $\lambda$10830 $\mathring{A}$ line as a probe of winds and accretion in young stars in Lupus and Upper Scorpius
• Revisiting the Helium and Hydrogen Accretion Indicators at TWA 27B: Weak Mass Flow at Near-Freefall Velocity
• The NEMESIS Catalogue of Young Stellar Objects for the Orion Star Formation Complex. I. General description of data curation
• Circumstellar disk accretion across the Lagoon Nebula: the influence of environment and stellar mass
• Discovery of Two Different Full Disk Evolutionary Patterns of M-type T Tauri Stars with LAMOST DR8
• Occurrence rates of accreting companions from a new method for computing emission-line survey sensitivity: application to the H-alpha Giant Accreting Protoplanet Survey