| Observation data EpochJ2000 EquinoxJ2000 | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 37m 10.79880s[1] |
| Declination | +17° 33′ 53.3332″[1] |
| Apparent magnitude (V) | 9.77±0.11[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | M0.0V[2] |
| Apparent magnitude (B) | 11.10±0.07[2] |
| Apparent magnitude (V) | 9.77±0.11[2] |
| Apparent magnitude (G) | 8.878±0.003[2] |
| Apparent magnitude (J) | 6.674±0.024[2] |
| Apparent magnitude (H) | 6.031±0.016[2] |
| Apparent magnitude (K) | 5.862±0.024[2] |
| Astrometry | |
| Radial velocity (Rv) | −58.64±0.16[1] km/s |
| Proper motion (μ) | RA: −764.414mas/yr[1] Dec.: 337.883mas/yr[1] |
| Parallax (π) | 100.0232±0.0208 mas[1] |
| Distance | 32.608 ± 0.007 ly (9.998 ± 0.002 pc) |
| Details[2] | |
| Mass | 0.439±0.011 M☉ |
| Radius | 0.439±0.003 R☉ |
| Luminosity (bolometric) | 0.03631±0.00018 L☉ |
| Surface gravity (log g) | 5.20±0.07 cgs |
| Temperature | 3803±10 K |
| Metallicity [Fe/H] | −0.43±0.04 dex |
| Rotation | 37.5±0.4 d |
| Rotational velocity (v sin i) | <2.0 km/s |
| Age | 2-8 Gyr |
| Other designations | |
| BD+17 1320,GJ 239,HD 260655,HIP 31635,CCDM J06372+1734A,WDS J06372+1733A,Ci 20 393,G 110-5,G 109-14,G 105-49,LFT 477,LHS 1858,LSPM J0637+1733,LTT 11880,NLTT 16743,PLX 1538,PM J06371+1733,Wolf 287,TOI-4599,TIC 307809773,TYC 1333-1683-1,GCRV 4273,IRAS 06342+1736,2MASS J06371092+1733526[3][2] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 260655 (also known asGJ 239 orTOI-4599)[2] is a relatively bright and cool M0 Vred dwarf star located 33light-years (10parsecs) away from theSolar System in the constellation ofGemini. HD 260655 has two confirmed rocky planets, named HD 260655 b[4][5] and HD 260655 c, that were discovered in 2022. Both planets were detected by theTESS mission and confirmed independently with archival and new preciseradial velocity data obtained with theHIRES observatory since 1998, and theCARMENES survey instruments since 2016.[2]
Thestar is among the earliest-type M dwarfs in the night sky. Its mass is 0.439 times that of theSun, and its radius is also 0.439 times that of the Sun. It has a temperature of 3,803 K (3,530 °C; 6,386 °F) and arotation period of 37.5 days.[2] Other designations of HD 260655 include Wolf 287, GJ 239, TOI-4599, HIP 31635 and LHS 1858.[3]
Themass of planet b is 2.14 ME, with aradius of 1.240 R🜨, and planet c has a mass of 3.09 ME, with a radius of 1.533 R🜨, making both planetssuper-Earths.[2] Theequilibrium temperature of HD 260655 b is 709 K (436 °C; 817 °F), while HD 260655 c sits at a temperature of 557 K (284 °C; 543 °F).[2][6] The orbital period of HD 260655 b is 2.77 days, while HD 260655 c has an orbital period of 5.71 days.[2]
Both planets are ideal candidates for future study of exoplanetatmospheres due to their closeness and their brightred dwarf star. However, as of 2022, there is no evidence that HD 260655 b or HD 260655 c have atmospheres.[7] HD 260655 is also the fourth-closest known system with multiple transiting exoplanets, afterHD 219134,LTT 1445, andAU Microscopii.[8]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 2.14±0.34 M🜨 | 0.02933±0.00024 | 2.76953±0.00003 | 0.039+0.043 −0.023 | 87.35±0.14° | 1.240±0.023 R🜨 |
| c | 3.09±0.48 M🜨 | 0.04749±0.00039 | 5.70588±0.00007 | 0.038+0.036 −0.022 | 87.79±0.08° | 1.533+0.051 −0.046 R🜨 |
