| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Octans |
| Right ascension | 21h 25m 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 as2MASS J21252752-8138278) is the primary of a possible trinarystar system located at a distance of 34.5 parsecs fromEarth in the southern direction in the constellation ofOctans. It is aBY Draconis variable, with large starspots causing it to change brightness as it rotates every 13 hours.[3]
TYC 9486-927-1 has rapid rotation andcoronal andchromospheric activity suggestive of a young age. Observations and multi-epochradial velocity data suggest that TYC 9486-927-1 is a single, rapidly rotating star rather than aspectroscopic or tightvisual 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 ared dwarf star of spectral class M5.5. Its projected separation from the primary would be 62,700AU. The candidate tertiary companion is 2MASS J21192028–8145446 - of spectral class M6 or M7 and at a projected separation of 31,000AU from the primary.[5]: 7
The planet2MASS J21265040-8140293 orbits TYC 9486-927-1 at a projected separation of7400 AU.[5] With a mass from 11.6 to 15Jupiter 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] | — | — | — |
