In the course of our search for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY – SPY) we discovered HE2209−1444 to be a double-lined system consisting of two DA white dwarfs. From the analysis of the radial velocity curve we determined the period of the system to be P = 6h38m47s. The semi-amplitudes for both individual components are 109 km s−1 each. A model atmosphere analysis enabled us to derive individual temperatures for both components (8490 K and 7140 K, resp.) and masses of 0.58 M for each component. The total mass of the system is 1.15 ± 0.07 M . The system will lose angular momentum due to gravitational wave radiation and therefore will merge within 5 Gyrs – less than a Hubble time. HE 2209−1444 is the second massive, short period double degenerate detected by SPY. Its total mass is about 20% below the Chandrasekhar mass limit and therefore it does not qualify as a potentional SN Ia progenitor. However, together with our previous detections it supports the view that Chandrasekhar mass systems do exist.
|Journal||Astronomy and Astrophysics|
|Publication status||Published - Nov 2003|