| |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lynx |
| G 107-69 | |
| Right ascension | 07h30m 42.7784s[1] |
| Declination | +48° 11′ 58.5889″[1] |
| Apparent magnitude (V) | 13.2[2] |
| G 107-70 | |
| Right ascension | 07h30m 46.9572s[1] |
| Declination | +48° 10′ 06.2765″[1] |
| Apparent magnitude (V) | 15.00[3] |
| Characteristics | |
| Spectral type | M4.5+DA+DA |
| Astrometry | |
| G 107-69 | |
| Radial velocity (Rv) | −56.486±0.0035[4] km/s |
| Proper motion (μ) | RA: −201.282±0.027 mas/yr[1] Dec.: −1,272.162±0.020 mas/yr[1] |
| Parallax (π) | 88.7231 ± 0.0298 mas[1] |
| Distance | 36.76 ± 0.01 ly (11.271 ± 0.004 pc) |
| Details | |
| G 107-69A | |
| Mass | 0.17[2] M☉ |
| Radius | 0.21[5] R☉ |
| Luminosity | 0.003[6] L☉ |
| Surface gravity (log g) | 5.0±0.13[7] cgs |
| Temperature | 3,200±25[7] K |
| Metallicity [Fe/H] | −0.15±0.09[7] dex |
| G 107-69B | |
| Mass | 0.08[2] M☉ |
| G 107-70A | |
| Mass | 0.634±0.01[3] M☉ |
| G 107-70B | |
| Mass | 0.599±0.01[3] M☉ |
| Other designations | |
WDS J07307+4813, 2MASS J07304735+4810275, 2MASS J07304280+4811599 GJ 275.2, LHS 229, LHS 230, EGGR 52, WD 0727+482 | |
| Database references | |
| SIMBAD | G 107-69 |
| G 107-70 | |
G 107-69/70 is a quadruple system, consisting of the astrometric binary G 107-69 and the resolved binary G 107-70.[2] The system is 36.76 light years (11.27 parsecs) from Earth.[1] G 107-69 and G 107-70 are separated by 103.2 arcseconds, or 1163 astronomical units (AU).[2]
G 107-69A is a red dwarf star with a spectral type of M4.5[7] and a mass of about 0.17 M☉. G 107-69B has a mass of about 0.08 M☉or84 MJ. The binary has a period of 0.94 years and a predicted separation of about 50 mas.[2] From its mass G 107-69B could be either a low-mass red dwarf star or a brown dwarf.
G 107-70 (also called WD 0727+482) is a pair of white dwarfs, with both having similar mass, brightness and atmospheric composition.[3][8] The binary was first partially resolved in 1976.[9] Later Nelan et al. fully resolved the orbit of this binary with Hubble's Fine Guidance Sensor and found an orbital period of 18.84±0.02 years and a semi-major axis of 663.62±0.79 mas.[3] At a distance of 11.27 parsecs the semi-major axis is about 7.5 AU.
By resolving the orbit of the G 107-70 system Nelan et al. were able to calculate the dynamical mass of each component: G 107-70A has a mass of 0.634±0.01 M☉ and G 107-70B has a mass of 0.599±0.01 M☉.[3] Both white dwarfs have a spectral type of DA, which indicates an atmosphere dominated by hydrogen.[8]
