SDSS J184037.78+642312.3: THE FIRST PULSATING EXTREMELY LOW MASS WHITE DWARF
SDSS J184037.78+642312.3: THE FIRST PULSATING EXTREMELY LOW MASS WHITE DWARF
We report the discovery of the first pulsating extremely low mass (ELM) white dwarf (WD), SDSS J184037.78+642312.3 (hereafter J1840). This DA (hydrogen-atmosphere) WD is by far the coolest and the lowest-mass pulsating WD, with Teff = 9100 \pm 170 K and log g = 6.22 \pm 0.06, which corresponds to …