G 196-3
Star in the constellation Ursa Major
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G 196-3 is a young low-mass M dwarf type star which is about 100 million years old. The star is located within the Ursa Major constellation about 71.1 light years away[2] from the Earth. During observations by Instituto de Astrofísica de Canarias in Tenerife, Spain in 1998, a substellar-mass object was discovered to orbit approximately 300 astronomical units (AU) from the star. It was detected using direct imaging.[8][9][10][11]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major[1] |
| Right ascension | 10h 04m 21.4627s[2] |
| Declination | 50° 23′ 13.386″[2] |
| Apparent magnitude (V) | 11.7[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | M3.0V[5] |
| U−B color index | +1.67[citation needed] |
| B−V color index | +1.16[citation needed] |
| Astrometry | |
| Radial velocity (Rv) | 11.7[2] km/s |
| Proper motion (μ) | RA: −141.079[2] mas/yr Dec.: −202.336[2] mas/yr |
| Parallax (π) | 45.8541±0.0188 mas[2] |
| Distance | 71.13 ± 0.03 ly (21.808 ± 0.009 pc) |
| Details | |
| Mass | 0.525[6] M☉ |
| Radius | 0.52[7] R☉ |
| Luminosity | 0.00431[6] L☉ |
| Surface gravity (log g) | 5.0[4] cgs |
| Temperature | 3,485[6] K |
| Rotation | 1.315 days[7] |
| Rotational velocity (v sin i) | 16.6[7] km/s |
| Age | 38[3] Myr |
| Other designations | |
| TYC 3440-13-1, NLTT 23293 | |
| Database references | |
| SIMBAD | data |
Substellar companion
Observations of the substellar object were performed on January 25, 1998 where a faint red companion was present 16.2 arc seconds southwest of the star. A comparison of images taken at different wavelengths was done using low-intermediate-resolution spectroscopy confirmed the presence of a substellar object which was named G 196-3B. The Further observations confirmed the discovery when the team of Rafael Rebolo obtained R & I broadband photometry on March 19, 1998. The TCS Telescope showed its very cool nature in near-infrared (K Band). The comparison of the optical and infrared magnitudes including dust condensation has allowed astronomers to conclude that the substellar object was 25–10+15 Jupiter masses or simply 25 masses that of the Jovian-planet Jupiter. This was the second[12][13] discovery of a brown dwarf that was found around a low-mass star whose age[14] was relatively young. The separation of the star and the substellar object has suggested that both were parts of a fragment from a collapsing cloud although another possible scenario suggests that it originated from a dissipated protoplanetary disk.[15][8][16][17][18][19]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| B | 26±1 MJ | 350±1 | — | — | — | 1.36±0.23 RJ |