| Observation data EpochJ2000 EquinoxJ2000 | |
|---|---|
| Constellation | Centaurus[1] |
| Right ascension | 11h 41m 02.46847s[2] |
| Declination | −44° 24′ 18.6867″[2] |
| Apparent magnitude (V) | 7.762[3] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | K4.5Vk:[4] |
| Astrometry | |
| Radial velocity (Rv) | 13.55±0.13[2] km/s |
| Proper motion (μ) | RA: −660.634mas/yr[2] Dec.: 242.096mas/yr[2] |
| Parallax (π) | 78.2268±0.0182 mas[2] |
| Distance | 41.694 ± 0.010 ly (12.783 ± 0.003 pc) |
| Details[5] | |
| Mass | 0.653±0.028 M☉ |
| Radius | 0.630±0.027 R☉ |
| Luminosity (bolometric) | 0.18332±0.00059 L☉ |
| Surface gravity (log g) | 4.654±0.057 cgs |
| Temperature | 4675±53 K |
| Metallicity[Fe/H] | −0.505±0.027 dex |
| Rotation | ~30 days |
| Rotational velocity (v sin i) | 2.47±0.30 km/s |
| Age | 6.88±4.27 Gyr |
| Other designations | |
| CD−43 7228,GJ 435,HD 101581,HIP 56998,SAO 222956,LHS 2441,TOI-6276,TIC 397362481[3] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 101581 (also otherdesignationsTOI-6276 andGJ 435) is a nearbyK-type main-sequence star located in the constellationCentaurus,[1] approximately 41.7light-years (12.8parsecs) away, based on a parallax of 78.227mas.[5] At anapparent magnitude of 7.8, it is too faint to be seen with the naked eye, although it can be viewed with a small telescope.[6][7]
HD 101581 has aspectral type of K5V, which classifies it as amain sequence star (similar to the Sun) having the core hydrogen converted into helium. It has 0.65 times theSolar mass and 0.63 times theSolar radius while its age is estimated to be about 6.9billion years old.[5] Its surface has aneffective temperature of 4633K[6] giving it the typical orange hue of aK-type star.[8][1] Themetallicity index of it is−0.344±0.059, indicating an iron-to-hydrogen ratio 45% that of the Sun.[6]
In 2024, two validated Earth-size planets orbiting HD 101581 were discovered via thetransit method byTESS. These planets have orbital periods of 4.5 and 6.2 days, respectively. A candidate third small transiting planet in a wider orbit was possibly detected.[5][9] The host star is the brightest star (invisual magnitude) with multiple known transiting Earth-size exoplanets, which should enable the atmospheric study of its orbiting planets via transmission spectroscopy in the near-future.[5][9]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | — | 0.046±0.0007 | 4.46569+0.00029 −0.00032 | — | 87.78+0.27 −0.2° | 0.956+0.061 −0.063 R🜨 |
| c | — | 0.0573±0.0009 | 6.20401+0.00054 −0.00044 | — | 87.93+0.19 −0.15° | 0.990±0.070 R🜨 |
| (unconfirmed) | — | 0.0671±0.001 | 7.8708+0.0016 −0.0011 | — | 87.88+0.15 −0.14° | 0.982+0.114 −0.098 R🜨 |
