The ASAS-SN catalogue of variable stars VI: an all-sky sample of δ Scuti stars
Abstract
We characterize an all-sky catalogue of ∼8400 δ Scuti variables in ASAS-SN, which includes ∼3300 new discoveries. Using distances from Gaia DR2, we derive period-luminosity relationships for both the fundamental mode and overtone pulsators in the WJK, V, Gaia DR2 G, J, H, Ks, and W1 bands. We find that the overtone pulsators have a dominant overtone mode, with many sources pulsating in the second overtone or higher order modes. The fundamental mode pulsators have metallicity-dependent periods, with log10(P) ∼ -1.1 for $\rm [Fe/H]\lt -0.3$ and log10(P) ∼ -0.9 for $\rm [Fe/H]\gt 0$ , which leads to a period-dependent scale height. Stars with $P\gt 0.100\, \rm d$ are predominantly located close to the Galactic disc ( $\rm |\mathit{ Z}|\lt 0.5\, kpc$ ). The median period at a scale height of $Z\sim 0\, \rm kpc$ also increases with the Galactocentric radius R, from log10(P) ∼ -0.94 for sources with $R\gt 9\, \rm kpc$ to log10(P) ∼ -0.85 for sources with $R\lt 7\, \rm kpc$ , which is indicative of a radial metallicity gradient. To illustrate potential applications of this all-sky catalogue, we obtained 30 min cadence, image subtraction TESS light curves for a sample of 10 fundamental mode and 10 overtone δ Scuti stars discovered by ASAS-SN. From this sample, we identified two new δ Scuti eclipsing binaries, ASASSN-V J071855.62-434247.3 and ASASSN-V J170344.20-615941.2 with short orbital periods of Porb = 2.6096 and 2.5347 d, respectively.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2020
- DOI:
- arXiv:
- arXiv:1910.14187
- Bibcode:
- 2020MNRAS.493.4186J
- Keywords:
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- stars: binaries: eclipsing;
- stars: variables: Delta Scuti;
- stars: variables;
- catalogues;
- surveys;
- catalogues - surveys;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted by MNRAS