CHROMOSPHERICALLY ACTIVE STARS IN THE RADIAL VELOCITY EXPERIMENT (RAVE) SURVEY. I. THE CATALOG
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia)
- Department of Astronomy and Astrophysics, Villanova University, 800 E Lancaster Avenue, Villanova, PA 19085 (United States)
- Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)
- Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, 11 rue de l'Université, F-67000 Strasbourg (France)
- Sydney Institute for Astronomy, School of Physics A28, Sydney, NSW 2006 (Australia)
- Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany)
- Research School of Astronomy and Astrophysics, Australia National University, Weston Creek, Canberra, ACT 2611 (Australia)
- Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom)
- INAF Osservatorio Astronomico di Padova, I-36012 Asiago (Italy)
- Department of Physics and Astronomy, University of Victoria, Victoria BC, V8P 5C2 (Canada)
- Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia)
- Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, RH5 6NT (United Kingdom)
- Johns Hopkins University, Homewood Campus, 3400 North Charles Street, Baltimore, MD 21218 (United States)
RAVE, the unbiased magnitude limited survey of southern sky stars, contained 456,676 medium-resolution spectra at the time of our analysis. Spectra cover the Ca II infrared triplet (IRT) range, which is a known indicator of chromospheric activity. Our previous work classified all spectra using locally linear embedding. It identified 53,347 cases with a suggested emission component in calcium lines. Here, we use a spectral subtraction technique to measure the properties of this emission. Synthetic templates are replaced by the observed spectra of non-active stars to bypass the difficult computations of non-local thermal equilibrium profiles of the line cores and stellar parameter dependence. We derive both the equivalent width of the excess emission for each calcium line on a 5 Å wide interval and their sum EW{sub IRT} for ∼44,000 candidate active dwarf stars with signal-to-noise ratio >20, with no cuts on the basis of the source of their emission flux. From these, ∼14,000 show a detectable chromospheric flux with at least a 2σ confidence level. Our set of active stars vastly enlarges previously known samples. Atmospheric parameters and, in some cases, radial velocities of active stars derived from automatic pipelines suffer from systematic shifts due to their shallower calcium lines. We re-estimate the effective temperature, metallicity, and radial velocities for candidate active stars. The overall distribution of activity levels shows a bimodal shape, with the first peak coinciding with non-active stars and the second with the pre-main-sequence cases. The catalog will be made publicly available with the next RAVE public data releases.
- OSTI ID:
- 22270811
- Journal Information:
- Astrophysical Journal, Vol. 776, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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