HD 101581

Last updated
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
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 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]

Contents

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 an 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]

The HD 101581 planetary system [5]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b—0.046±0.00074.46569+0.00029
−0.00032		—87.78+0.27
−0.2 ° 		0.956+0.061
−0.063  R🜨
c—0.0573±0.00096.20401+0.00054
−0.00044		—87.93+0.19
−0.15 ° 		0.990±0.070  R🜨
(unconfirmed)—0.0671±0.0017.8708+0.0016
−0.0011		—87.88+0.15
−0.14 ° 		0.982+0.114
−0.098  R🜨

See also

References

  1. 1 2 3 "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008. Retrieved 18 January 2025.
  2. 1 2 3 4 5 6 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.
  3. 1 2 "HD 101581". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 18 January 2025.
  4. ↑ 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.
  5. 1 2 3 4 5 6 7 8 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 .
  6. 1 2 3 "The Extrasolar Planet Encyclopaedia — HD 101581 c". Extrasolar Planets Encyclopaedia . Paris Observatory . Retrieved January 18, 2025.
  7. ↑ "HD 101581". stellarcatalog.com. Retrieved 2025-01-18.
  8. ↑ "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.
  9. 1 2 "Two Earth-sized exoplanets orbiting nearby star detected". phys.org. Retrieved 2025-01-18.
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