Gliese 367

Gliese 367 (GJ 367, formally named Añañuca[5]) is a red dwarf star 30.7 light-years (9.4 parsecs) from Earth in the constellation of Vela. It is suspected to be a variable with amplitude 0.012 stellar magnitude and period 5.16 years.[6] A stellar multiplicity survey in 2015 failed to detect any stellar companions to Gliese 367.[7] It hosts three known exoplanets, Gliese 367 b, c & d.[8]

Gliese 367 / Añañuca
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension 09h 44m 29.83677s[1]
Declination −45° 46′ 35.4276″[1]
Apparent magnitude (V) 10.153±0.044[2]
Characteristics
Evolutionary stage Main sequence
Spectral type M1.0V[2]
Astrometry
Radial velocity (Rv)47.42±0.14[1] km/s
Proper motion (μ) RA: −462.621(14) mas/yr[1]
Dec.: −582.668(15) mas/yr[1]
Parallax (π)106.1727 ± 0.0141 mas[1]
Distance30.719 ± 0.004 ly
(9.419 ± 0.001 pc)
Details[2]
Mass0.454±0.011 M☉
Radius0.457±0.013 R☉
Luminosity0.0288±0.0027 L☉
Surface gravity (log g)4.777±0.026 cgs
Temperature3522±70 K
Metallicity [Fe/H]−0.01±0.12 dex
Rotation48±2 d
Rotational velocity (v sin i)0.48±0.02 km/s
Age8.0+3.8
−4.6,[2] 0.057+0.003
−0.002[3] Gyr
Other designations
Añañuca, CD−45 5378, GJ 367, HIP 47780, TOI-731, TIC 34068865, TYC 8168-2031-1, 2MASS J09442986-4546351[4]
Database references
SIMBADdata

Gliese 367's age is unclear. Modelling using stellar isochrones gives a young age of less than 60 million years old, but its orbit around the Milky Way is highly eccentric, unusual for a young star.[3] It may have been forced into such an orbit via a gravitational encounter.[3] Spectroscopic evidence presented in a 2023 study supports an old age for Gliese 367.[8]: 6 

Nomenclature

The designation Gliese 367 comes from the Gliese Catalogue of Nearby Stars. This was the 367th star listed in the first edition of the catalogue.

In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project.[9] The approved names, proposed by a team from Chile, were announced in June 2023. Gliese 367 is named Añañuca and its innermost planet is named Tahay, after names for the endemic Chilean wildflowers Phycella cyrtanthoides and Calydorea xiphioides.[5]

Planetary system

The star Gliese 367 was observed by TESS in February-March 2019, leading to its designation as an object of interest,[2] and by January 2021 additional radial velocity data suggested the existence of a short-period planet, albeit with low certainty.[10] The planet's existence was confirmed by both ground-based and satellite-based transit photometry data by December 2021.[2]

Gliese 367 b takes just 7.7 hours to orbit its star, one of the shortest orbits of any planet. Due to its close orbit, the exoplanet gets bombarded with radiation over 500 times what Earth receives from the Sun.[2][11] Dayside temperatures on GJ 367b are around 1,500 °C (1,770 K; 2,730 °F).[12] Due to its close orbit, it most likely is tidally locked.[13] The atmosphere of Gliese 367 b, due to the extreme temperatures, would have boiled away along with signs of life.[12] The core of GJ 367b is likely composed of iron and nickel, making its core similar to Mercury's core. The core of GJ 367b is extremely dense, making up most of the planet's mass.[12]

As of 2022, Gliese 367 b is the smallest known exoplanet within 10 parsecs of the Solar System,[14] and the second-least massive after Proxima Centauri d.

A direct imaging study in 2022 failed to find any additional planets or stellar companions around Gliese 367. This rules out any companions at distances greater than 5 AU with masses greater than 20 MJ (for an age of 5 billion years) or 1.5 MJ (for an age of 50 million years).[3] The discovery of two additional super-Earth-mass planets with periods of 11.5 and 34 days was published in 2023.[8]

The Gliese 367 planetary system[8]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Tahay 0.633±0.050 M🜨 0.00709±0.00027 0.3219225(2) 0.06+0.07
−0.04		 79.89+0.87
−0.85°		 0.699±0.024 R🜨
c ≥4.13±0.36 M🜨 — 11.5301±0.0078 0.09±0.07 — —
d ≥6.03±0.49 M🜨 — 34.369±0.073 0.14±0.09 — —

See also

References
  1. 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.
  2. Lam, Kristine W. F.; et al. (2021). "GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star". Science. 374 (6572): 1271–1275. arXiv:2112.01309. Bibcode:2021Sci...374.1271L. doi:10.1126/science.aay3253. PMID 34855492. S2CID 244799656.
  3. Brandner, Wolfgang; Calissendorff, Per; Frankel, Neige; Cantalloube, Faustine (2022). "High-contrast, high-angular resolution view of the GJ 367 exoplanet system". Monthly Notices of the Royal Astronomical Society. 513: 661–669. arXiv:2204.02998. Bibcode:2022MNRAS.513..661B. doi:10.1093/mnras/stac961.
  4. "CD-45 5378". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-12-04.
  5. "2022 Approved Names". nameexoworlds.iau.org. IAU. Retrieved 7 June 2023.
  6. Hosey, Altonio D.; Henry, Todd J.; Jao, Wei-Chun; Dieterich, Sergio B.; Winters, Jennifer G.; Lurie, John C.; Riedel, Adric R.; Subasavage, John P. (2015). "The Solar Neighborhood XXXVI. The Long-Term Photometric Variability of Nearby Red Dwarfs in the V RI Optical Bands". The Astronomical Journal. 150 (1): 6. arXiv:1503.02100. Bibcode:2015AJ....150....6H. doi:10.1088/0004-6256/150/1/6. S2CID 13913564.
  7. Ward-Duong, K.; Patience, J.; De Rosa, R. J.; Bulger, J.; Rajan, A.; Goodwin, S. P.; Parker, Richard J.; McCarthy, D. W.; Kulesa, C. (2015). "The M-dwarfs in Multiples (Min Ms) survey – I. Stellar multiplicity among low-mass stars within 15 pc★". Monthly Notices of the Royal Astronomical Society. 449 (3): 2618–2637. arXiv:1503.00724. Bibcode:2015MNRAS.449.2618W. doi:10.1093/mnras/stv384.
  8. Goffo, Elisa; Gandolfi, Davide; et al. (September 2023). "Company for the ultra-high density, ultra-short period sub-Earth GJ 367 b: discovery of two additional low-mass planets at 11.5 and 34 days". The Astrophysical Journal Letters. 955 (1): L3. arXiv:2307.09181. Bibcode:2023ApJ...955L...3G. doi:10.3847/2041-8213/ace0c7.
  9. "List of ExoWorlds 2022". nameexoworlds.iau.org. IAU. 8 August 2022. Retrieved 27 August 2022.
  10. Palatnick, Skyler; Kipping, David; Yahalomi, Daniel (2021). "Validation of HD 183579b Using Archival Radial Velocities: A Warm Neptune Orbiting a Bright Solar Analog". The Astrophysical Journal Letters. 909 (1): L6. arXiv:2101.12137. Bibcode:2021ApJ...909L...6P. doi:10.3847/2041-8213/abe0bb. S2CID 231719821.
  11. "ExoFOP TIC 34068865". exofop.ipac.caltech.edu. Retrieved 7 December 2021.
  12. "Iron-Rich Sub-Earth Exoplanet Found Orbiting Gliese 367 | Sci-News.com". Breaking Science News | Sci-News.com. 3 December 2021. Retrieved 2021-12-03.
  13. Mann, Adam (2021-12-02). "Metal Planet Orbits Its Star Every 7.7 Hours". The New York Times. ISSN 0362-4331. Retrieved 2021-12-03.
  14. "Planetary Systems Composite Data". NASA Exoplanet Archive. Retrieved 7 December 2021.
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