Abstract
Abstract I have used high-precision photometry and astrometry from the early installment of the third data release of Gaia (EDR3) to perform a survey for members of the stellar populations within the Sco-Cen complex, which consist of Upper Sco, UCL/LCC, the V1062 Sco group, Ophiuchus, and Lupus. Among Gaia sources with σ π < 1 mas, I have identified 10,509 candidate members of those populations. I have compiled previous measurements of spectral types, Li equivalent widths, and radial velocities for the candidates, which are available for 3169, 1420, and 1740 objects, respectively. In a subset of candidates selected to minimize field star contamination, I estimate that the contamination is ≲1% and the completeness is ∼90% at spectral types of ≲M6–M7 for the populations with low extinction (Upper Sco, V1062 Sco, UCL/LCC). I have used that cleaner sample to characterize the stellar populations in Sco-Cen in terms of their initial mass functions, ages, and space velocities. For instance, all of the populations in Sco-Cen have histograms of spectral types that peak near M4–M5, which indicates that they share similar characteristic masses for their initial mass functions (∼0.15–0.2 M ⊙). After accounting for incompleteness, I estimate that the Sco-Cen complex contains nearly 10,000 members with masses above ∼0.01 M ⊙. Finally, I also present new estimates for the intrinsic colors of young stars and brown dwarfs (≲20 Myr) in bands from Gaia EDR3, the Two Micron All Sky Survey, the Wide-field Infrared Survey Explorer, and the Spitzer Space Telescope.
Highlights
I have used high-precision photometry and astrometry from the early installment of the third data release of Gaia (EDR3) to perform a survey for members of the stellar populations within the Sco-Cen complex, which consist of Upper Sco, Upper Centaurus-Lupus (UCL)/LCC, the V1062 Sco group, Ophiuchus, and Lupus
More recent studies have suggested that UCL and LCC are two sections of a continuous distribution of stars (Rizzuto et al 2011) and have identified an additional compact group associated with V1062 Sco (Roser et al 2018; Damiani et al 2019)
I have used high-precision photometry and astrometry from Gaia EDR3 to identify candidate members of the stellar populations within the Sco-Cen complex, which consist of Ophiuchus, Lupus, Upper Sco, V1062 Sco, and UCL/LCC
Summary
Scorpius-Centaurus (Sco-Cen, Preibisch & Mamajek 2008) is the nearest OB association to the Sun (100– 200 pc, de Zeeuw et al 1999) It contains several thousand stars with ages of 10–20 Myr that historically have been divided into three subgroups: Upper Sco, Upper Centaurus-Lupus (UCL), and Lower CentaurusCrux (LCC, Blaauw 1964; de Zeeuw et al 1999). The Gaia mission is performing an all-sky survey to measure precise photometry, proper motions, and parallaxes for more than a billion stars (Perryman et al 2001; de Bruijne 2012; Gaia Collaboration et al 2016). Those data are extremely valuable for identifying candidate members of nearby stellar associations. A separate study identifies and classifies the circumstellar disks among the Luhman candidate members of Sco-Cen (Luhman 2021)
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