期刊
ASTRONOMICAL JOURNAL
卷 160, 期 1, 页码 -出版社
IOP Publishing Ltd
DOI: 10.3847/1538-3881/ab9599
关键词
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资金
- NASA [80NSSC 18K0444, NNH14CK55B]
- National Optical Astronomy Observatory (NOAO) [2018A-0098, 2019A-0127]
- NSF
- Alfred P. Sloan Foundation
- U.S. Department of Energy Office of Science
- Center for High-Performance Computing at the University of Utah
- Brazilian Participation Group
- Carnegie Institution for Science
- Carnegie Mellon University
- Chilean Participation Group
- French Participation Group
- Harvard-Smithsonian Center for Astrophysics
- Instituto de Astrofisica de Canarias
- Johns Hopkins University
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo
- Korean Participation Group
- Lawrence Berkeley National Laboratory
- Leibniz Institut fur Astrophysik Potsdam (AIP)
- Max-PlanckInstitut fur Astronomie (MPIA Heidelberg)
- Max-Planck-Institut fur Astrophysik (MPA Garching)
- Max-Planck-Institut fur Extraterrestrische Physik (MPE)
- National Astronomical Observatories of China
- New Mexico State University
- New York University
- University of Notre Dame
- Observatario Nacional/MCTI
- Ohio State University
- Pennsylvania State University
- Shanghai Astronomical Observatory
- United Kingdom Participation Group
- Universidad Nacional Autonoma de Mexico
- University of Arizona
- University of Colorado Boulder
- University of Oxford
- University of Portsmouth
- University of Utah
- University of Virginia
- University of Washington
- University of Wisconsin
- Vanderbilt University
- Yale University
- Eberly College of Science
- Pennsylvania Space Grant Consortium
- [GN-2018A-Q-115]
- [GN-2018A-Q-218 (NOAO 2018A-0066)]
- [GN2019A-Q-317 (2019A-0086)]
- [GS-2019A-Q-125 (2019A-0053)]
- [GN-2020A-Q-218 (2020A-0066)]
We have refined the census of stars and brown dwarfs in the Upper Sco association (similar to 10 Myr, similar to 145 pc) by (1) updating the selection of candidate members from our previous survey to include the high-precision astrometry from the second data release of Gaia, (2) obtaining spectra of a few hundred candidate members to measure their spectral types and verify their youth, and (3) assessing the membership (largely with Gala astrometry) of 2020 stars toward Upper Sco that show evidence of youth in this work and previous studies. We arrive at a catalog of 1761 objects that are adopted as members of Upper Sco. The distribution of spectral types among the adopted members is similar to those in other nearby star-forming regions, indicating a similar initial mass function. In previous studies, we have compiled mid-infrared photometry from the Wide-field Infrared Survey Explorer and the Spitzer Space Telescope for members of Upper Sco and used those data to identify the stars that show evidence of circumstellar disks; we present the same analysis for our new catalog of members. As in earlier work, we find that the fraction of members with disks increases with lower stellar masses, ranging from less than or similar to 10% for >1 M-circle dot to similar to 22% for 0.01-0.3 M-circle dot. Finally, we have estimated the relative ages of Upper Sco and other young associations using their sequences of low-mass stars in M-GRP versus G(BP) - G(Rp). This comparison indicates that Upper Sco is a factor of two younger than the beta Pic association (21-24 Myr) according to both nonmagnetic and magnetic evolutionary models.
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