Abstract
We characterize an all-sky catalogue of similar to 8400 delta Scuti variables in ASAS-SN, which includes similar to 3300 new discoveries. Using distances from Gaia DR2, we derive period-luminosity relationships for both the fundamental mode and overtone pulsators in the W-JK, V, Gaia DR2 G, J, H, K-s, and W-1 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 log(10)(P) similar to -1.1 for [Fe/H] 0, which leads to a period-dependent scale height.
Stars with P > 0.100d are predominantly located close to the Galactic disc (vertical bar Z vertical bar 9 kpc to log(10)(P) similar to -0.85 for sources with R < 7 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 delta Scuti stars discovered by ASAS-SN.
From this sample, we identified two new delta Scuti eclipsing binaries, ASASSN-V J071855.62-434247.3 and ASASSN-V J170344.20-615941.2 with short orbital periods of P-orb = 2.6096 and 2.5347 d, respectively.