New time-series photometry of the magnetic white dwarf Star Feige 7
Abstract
Existing photometry of the magnetic helium-rich white dwarf Feige 7 is used to derive the parameters Teff=18 480 K and log g=8.74 and a frequency of variability of 10.94192 d-1 (period 2.19340 h). New time-series photometry of Feige 7 is presented, covering full cycles of variability in the UBVRI and ugriz filters, which allows the wavelength dependence of the two amplitudes in the double wave light curve to be determined. Amplitudes are virtually constant for wavelengths longer than 5 000 Å, but increase sharply for shorter wavelengths. A simple model consisting of two large cool spots 180° apart on the surface of star provides a reasonable description of the data.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- December 2024
- DOI:
- Bibcode:
- 2024PASA...41..101K
- Keywords:
-
- Stars: individual: Feige 7;
- stars: rotation;
- stars: white dwarfs