====== Double white dwarfs ====== ^Name ^Period ^Pdot ^d ^M2 ^q ^M1 ^i ^Mv ^V ^RA ^DEC ^l ^b | ^ ^[s] ^[s/s] ^[pc] ^Msun ^ ^Msun ^[deg] ^ ^ ^[h:m:s] ^[d:m:s] ^[deg] ^[deg] | |[[#SDSS J0651+2844]] | 765.4+/-7.9 | ? | ~1000 | 0.50 | 0.5 | 0.25 | 86.9+1.6-1 | ? | g=19.1 | 06 51 33.338 | +28 44 23.37 | 186.93 | 12.69 | |[[#SDSS J0935+4411]] | 1188+/-44 | ? | ~660 | >0.14 | ? | 0.32 | ? | ? | g=17.7 | 09 35 XX| +44 11 YY | | | |[[#SDSS J0106-1000]] | 2346+/-2 | ? | ~2400 | 0.43 | 0.4 | 0.17 | 67+/-13 | ? | g=19.8 | 01 06 57.39 | -10 00 03.3 | 135.72 | -72.47 | |[[#SDSS J1630+4233]] | 2390+/-4 | ? | ~830 | >0.52 | ? | 0.31 | ? | ? | g= | 16 30 XX| +42 33 YY | | | |[[#SDSS J1053+5200]] | 3680+/-10| ? | ~1100 | >0.26 | ? | 0.20 | ? | ? | g=18.87 | 10 53 53.89 | +52 00 31.0 | 156.40 | +56.79 | |[[#SDSS J0923+3028]] | 3884 | ? | 270 | >0.34 | ? | 0.23 | ? | ? | g= | 09 23 45.59 | +30 28 05.0 | 195.82 | 44.78 | |[[#SDSS J1436+5010]] | 3957 +/-10 |? | ~800 | >0.46 | ? | 0.24 | ? | ? | g=18.16 | 14 36 33.29 | +50 10 26.8 | 089.01 | +59.46 | |[[#WD 0957-666]] | 5269.81080+/-0.00007| ?| 135 +/- 20 | 0.32 +/- 0.03 | 1.15 +/- 0.10 | 0.37 +/- 0.02 | 50 -- 86 | 8.94 | 14.60 | 09 58 54.96 | --66 53 10.2 | 287.14 | -9.46 | |[[#SDSS J0755+4906]] | 5445 | ? | 2620 | >0.81| ? | 0.17 | ? | ? | | 07 55 52.40| +49 06 27.9 | 169.76 | 30.42| |[[#SDSS J0849+0445]] | 6800 | ? | 930 | >0.64| ? | 0.17 | ? | ? | | 08 49 10.13| +04 45 28.7 | 222.70| 28.27 | |[[#SDSS J0022-1014]] | 6902 | ? | 790 | >0.19| ? | 0.33 | ? | ? | | 00 22 07.65| -10 14 23.5 | 99.30 | -71.75 | |[[#SDSS J2119-0018]] | 7497 | ? | 2500 | >0.75| ? | 0.17 | ? | ? | | 21 19 21.96| -00 18 25.8 | 51.58 | -32.54 | |[[#SDSS J1234-0228]] | 7900 | ? | 780 | >0.09| ? | 0.23 | ? | ? | | 12 34 10.36| -02 28 02.8 | 294.25| 60.11 | |[[#WD 1101+364]] | 12503 +/- 5 | ? | 97 +/- 15 | 0.36 | 0.87 +/- 0.03 | 0.31 | 25 | 9.55 | 14.49 | 11 04 32.61 | +36 10 49.5 | 184.48 | +65.62 | |[[#WD 1704+4807BC]] | 12511 +/- 2 | ? | | 0.56 +/- 0.07 |0.70 +/- 0.03 | 0.39 +/- 0.05 | 61 | | 14.5 | 17 05 30.1 | +48 03 17 | 74.25 | +37.19 | For low mass SDSS systems see [[ADS>2011ApJ...727....3K|Kilic et al. 2011a]] still need to add more information (GN) ===== SDSS J0651+2844 ===== 12 minute system found by Kilic & co [[ADS>2011arXiv1107.2389B|Brown et al. 2011]] ===== SDSS J0935+4411 ===== 20 min system, Kilic & co [[ADS>2014MNRAS.444L...1K|Kilic et al. 2014]] ===== SDSS J0106-1000 ===== [[ADS>2011MNRAS.tmpL.233K|Kilic et al. 2011b]]\\ ===== SDSS J1053+5200 ===== Paper now out [[ADS>2010ApJ...716..122K|Kilic et al. 2010]]\\ Reported by Badenes in KITP conference, 2009, http://online.kitp.ucsb.edu/online/sdeath_c09/ as a short period double white dwarf. It has a radial velocity amplitude of 310 +/- 14 km/s. They observed the star as it was one of the targets discussed by [[ADS>2007ApJ...660.1451K|Kilic et al (2007)]] for being a very low mass white dwarf (0.19 Msun). Such stars are very likely to be binary as this one indeed is (TRM). The mass of the unseen (secondary) star is a lower limit calculated from the radial velocity amplitude and the 0.19 Msun mass for the primary. [[ADS>2007ApJ...660.1451K|Kilic et al (2007)]] lists a temperature of 15,900K, which combined with the mass of the brighter object should give a distance. ===== SDSS J1630+4233 ===== See [[ADS>2014ApJ...794...35G|Giannidas et al. 2014]] ===== SDSS J1436+5010 ===== Paper now out [[ADS>2010ApJ...716..122K|Kilic et al. 2010]]\\ Second system reported by Badenes at KITP conference, 2009, http://online.kitp.ucsb.edu/online/sdeath_c09/ (see SDSS J1053+5200). This is also another star from [[ADS>2007ApJ...660.1451K|Kilic et al (2007)]]. The radial velocity semi-amplitude K = 388 +/- 21 km/s, which leads to the lower limit on the mass of the secondary star assuming the quoted mass for the primary star. [[ADS>2007ApJ...660.1451K|Kilic et al (2007)]] list a temperature of 18,400 K cf 17,000 K from [[ADS>2006ApJS..167...40E|Eisenstein et al (2006)]] where this star was first identified as a low mass white dwarf. ===== WD 0957-666 ===== Period from [[ADS>1997MNRAS.288..538M|Moran et al (1997)]]; distance from [[ADS>1995ApJ...443..735B|Bragaglia et al (1995)]]. Uncertainty in the distance is a bit of a guess; formal uncertainties are lower, but things are never quite as good as formal uncertainties suggest. Nevertheless, this distance (which is based upon the apparent magnitude versus model atmosphere fits (with a 20% correction for the light of the companion which I have used to raise the absolute magnitude of the system by 0.2 mags), and should be pretty good. (TRM) Mass ratio q = M1/M2 (brighter over fainter). This is a double-lined system and so the mass ratio is well determined. (TRM) The masses are from [[ADS>1997MNRAS.288..538M|Moran et al (1997)]]. The inclination comes from taking a 2-sigma lower limit on sin i from [[ADS>1997MNRAS.288..538M|Moran et al (1997)]] together with an absence of observed eclipses from [[ADS>2002PASP..114..229H|Hoard & Wachter (2002)]] (TRM). ===== WD 1101+364 ===== [[ADS>1995MNRAS.275L...1M|Marsh (1995)]] discovered this star to be a binary. It is a double-lined system (TRM). The absolute magnitude has been corrected up by 0.75 mags from a straight model atmosphere fit because the system is a very equal double (TRM). Masses and inclination are not well constrained; mass ratio is OK (TRM). As usual for the double white dwarfs, the mass ratio = M(bright)/M(faint) (TRM). ===== WD 1704+4807BC ===== [[ADS>2000MNRAS.314..334M|Maxted et al (2000)]] discovered that this star was a close binary. It is part of a triple system with another white dwarf and hence the 'BC' designation (TRM). Mass ratio is ratio of masses of the bright over the faint component (TRM).