| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Octans |
| Right ascension | 21h25m 27.4805s[2] |
| Declination | −81° 38′ 27.692″[2] |
| Apparent magnitude (V) | 11.5 - 12.0[3] |
| Characteristics | |
| Spectral type | M1 V[4] |
| Variable type | BY Dra[3] |
| Astrometry | |
| Radial velocity (Rv) | 8.7±4.6[4] km/s |
| Proper motion (μ) | RA: 60.645(46) mas/yr[2] Dec.: −107.740(48) mas/yr[2] |
| Parallax (π) | 29.0266 ± 0.0401 mas[2] |
| Distance | 112.4 ± 0.2 ly (34.45 ± 0.05 pc) |
| Details | |
| Mass | 0.53[5] M☉ |
| Radius | 0.46[6] R☉ |
| Luminosity | 0.032[6] L☉ |
| Surface gravity (log g) | 4.3[7] cgs |
| Temperature | 3,490[8] K |
| Metallicity [Fe/H] | −1.3[7] dex |
| Rotation | 0.541945[3] days |
| Rotational velocity (v sin i) | 43.5±1.2[8] km/s |
| Age | 10-45[8] Myr |
| Other designations | |
2MASS J21252752-8138278, FT Octantis | |
| Database references | |
| SIMBAD | data |
TYC 9486-927-1 (also known as 2MASS J21252752-8138278) is the primary of a possible trinary star system located at a distance of 34.5 parsecs from Earth in the southern direction in the constellation of Octans. It is a BY Draconis variable, with large starspots causing it to change brightness as it rotates every 13 hours.[3]
TYC 9486-927-1 has rapid rotation and coronal and chromospheric activity suggestive of a young age. Observations and multi-epoch radial velocity data suggest that TYC 9486-927-1 is a single, rapidly rotating star rather than a spectroscopic or tight visual binary. However, it is still possible that TYC 9486-927-1 is an equal mass binary with a face-on orbit and close separation.[4]
The candidate secondary stellar companion is 2MASS J21121598–8128452. It is a red dwarf star of spectral class M5.5. Its projected separation from the primary would be 62,700 AU. The candidate tertiary companion is 2MASS J21192028–8145446 - of spectral class M6 or M7 and at a projected separation of 31,000 AU from the primary.[5]: 7
The planet 2MASS J21265040-8140293 orbits TYC 9486-927-1 at a projected separation of 7400 AU.[5] With a mass from 11.6 to 15 Jupiter masses, it is considered to be either a brown dwarf, or a giant planet.[9][10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| 2MASS J2126–8140/b | 13.3 (± 1.7)[11] MJ | 6,900[8] | 328 725 000[citation needed] | — | — | — |
