HD 101581
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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: −660.634 mas/yr[2] Dec.: 242.096 mas/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 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 101581 (also other designations TOI-6276 and GJ 435) is a nearby K-type main-sequence star located in the constellation Centaurus,[1] approximately 41.7 light-years (12.8 parsecs) away, based on a parallax of 78.227 mas.[5] At an apparent 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 a spectral type of K5V, which classifies it as a main sequence star (similar to the Sun) having the core hydrogen converted into helium. It has 0.65 times the Solar mass and 0.63 times the Solar radius while its age is estimated to be about 6.9 billion years old.[5] Its surface has an effective temperature of 4633 K[6] giving it the typical orange hue of a K-type star.[8][1] The metallicity index of it is −0.344±0.059, indicating a iron-to-hydrogen ratio 45% that of the Sun.[6]
Planetary system
In 2024, two validated Earth-size planets orbiting HD 101581 were discovered via the transit method by TESS. 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 (in visual 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🜨 |
See also
- K2-138, which has a similar architecture "peas-in-pod" of planetary system[5]
- LTT 1445, another nearby star system with transiting Earth-size planets[5]
References
- ^ a b c "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008. Retrieved 18 January 2025.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b "HD 101581". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 January 2025.
- ^ Gray, R. O.; Corbally, C. J.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 250741593.
- ^ a b c d e f g h Kunimoto, Michelle; Lin, Zifan; Millholland, Sarah; Venner, Alexander; Hinkel, Natalie R.; Shporer, Avi; Vanderburg, Andrew; Bailey, Jeremy; Brahm, Rafael (December 2024). "Two Earth-size Planets and an Earth-size Candidate Transiting the Nearby Star HD 101581". The Astronomical Journal. 169 (1): 47. arXiv:2412.08863. Bibcode:2025AJ....169...47K. doi:10.3847/1538-3881/ad9266.
- ^ a b c "The Extrasolar Planet Encyclopaedia — HD 101581 c". Extrasolar Planets Encyclopaedia. Paris Observatory. Retrieved January 18, 2025.
- ^ "HD 101581". stellarcatalog.com. Retrieved 2025-01-18.
- ^ "The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on 2013-12-03. Retrieved 2012-01-16.
- ^ a b "Two Earth-sized exoplanets orbiting nearby star detected". phys.org. Retrieved 2025-01-18.
