Discovery of a new blue large-amplitude pulsator in the SkyMapper DR2: SMSS J184506.82-300804.7
Abstract
We report the discovery of a new Blue Large-Amplitude Pulsator (BLAP), SMSS J184506-300804 (SMSS-BLAP-1) in Data Release 2 of the SkyMapper Southern Sky Survey. We conduct high-cadence photometric observations in the u band to confirm a periodic modulation of the light curve. SMSS-BLAP-1 has a ~19-min pulsation period with an amplitude of 0.2 mag in u band, and is similar to the classical BLAPs found by OGLE. From spectroscopic observations with the Wide-Field Spectrograph on the Australian National University 2.3m telescope, we confirm it as a low-gravity BLAP: best-fitting parameters from the non-LTE TLUSTY model are estimated as Teff = 29 020$^{+193}_{-34}$ K, logg = 4.661$^{+0.008}_{-0.143}$ (cm s-2), and logn(He)/n(H) = -2.722$^{+0.057}_{-0.074}$ dex. However, our BLAP exhibits a very He-deficient atmosphere compared to both low- and high-gravity BLAPs, which have logn(He)/n(H) in the range -0.41~-2.4.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2024
- DOI:
- arXiv:
- arXiv:2311.08775
- Bibcode:
- 2024MNRAS.529.1414C
- Keywords:
-
- stars: fundamental parameters;
- stars: individual: SMSS J184506.82-300804.7;
- stars: oscillations;
- stars: variable: general;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 9 pages, 8 figures, Accepted for publication in MNRAS