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L 168-9

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L 168-9 / Danfeng
Observation data
Epoch J2000      Equinox J2000
Constellation Tucana[1]
Right ascension 23h 20m 07.52452s[2]
Declination −60° 03′ 54.6447″[2]
Apparent magnitude (V) 11.02±0.06[3]
Characteristics
Evolutionary stage Main sequence
Spectral type M1V[3]
Apparent magnitude (B) 12.45±0.19[3]
Apparent magnitude (V) 11.02±0.06[3]
Apparent magnitude (G) 10.237±0.003[2]
Apparent magnitude (J) 7.941±0.019[3]
Apparent magnitude (H) 7.320±0.053[3]
Apparent magnitude (K) 7.082±0.031[3]
Astrometry
Radial velocity (Rv)29.44±0.21[2] km/s
Proper motion (μ) RA: −319.924 mas/yr[2]
Dec.: −127.782 mas/yr[2]
Parallax (π)39.7113 ± 0.0244 mas[2]
Distance82.13 ± 0.05 ly
(25.18 ± 0.02 pc)
Details[4]
Mass0.614±0.055 M☉
Radius0.604±0.037 R☉
Luminosity (bolometric)0.0723±0.0018 L☉
Surface gravity (log g)4.84±0.08 cgs
Temperature3842±32 K
Metallicity [Fe/H]0.06±0.13 dex
Rotation29±2 d
Other designations
Danfeng, CD−60 8051, GJ 4332, HIP 115211, L 168-9, LTT 9494, NLTT 56509, PM J23201-6003, TOI-134, TIC 234994474, TYC 9126-748-1, 2MASS J23200751-6003545, WISEA J232007.06-600355.8[5]
Database references
SIMBADdata

L 168-9 (also known as GJ 4332 or TOI-134, officially named Danfeng) is a red dwarf star located 82.1 light-years (25.2 parsecs) away from the Solar System in the constellation of Tucana. The star has about 61% the mass and 60% the radius of the Sun. It has a temperature of 3,842 K (3,569 °C; 6,456 °F) and a rotation period of 29 days. L 168-9 is orbited by one known exoplanet.

Nomenclature

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The designation L 168-9 comes from Luyten's first catalogue of stars with high proper motion.

In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project.[6] The approved names, proposed by a team from China, were announced in June 2023. L 168-9 is named Danfeng and its planet is named Qingluan, after mythological birds of ancient China.[7]

Planetary system

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The exoplanet L 168-9 b, officially named Qingluan, was discovered in 2020 using TESS. At the discovery, this terrestrial super-Earth was thought to have about 4.6 times the mass and 1.39 times the radius of Earth, and an estimated equilibrium temperature of 965 K (692 °C; 1,277 °F). L 168-9 b is a target for observation and atmospheric characterization with the James Webb Space Telescope,[3] and has been observed as one of its first targets.[8][9]

A newer study refined the planetary parameters of L 168-9 b. The newer research found a lower mass of 4.07 ME and a higher radius of 1.63 R🜨. These parameters imply a lower density of 5.18 g/cm3, in contrast to the previous value of 9.6 g/cm3. Given the lower density of the planet, it more likely has a pure rock composition, rather than a 50% iron core and 50% silicate mantle as previously proposed. The orbital parameters show little variation, while the equilibrium temperature was updated to 998±39 K.[4]

Transmission spectra of combined near- and mid-infrared observations by the James Webb Space Telescope showed no atmospheric features. However, further observations are required to rule out a thick (100 bar) carbon dioxide atmosphere, which could also explain the data.[10]

The L 168-9 planetary system[4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b / Qingluan 4.07±0.45 M🜨 0.0208±0.0006 1.40153±0 <0.21[3] 84.27±1.01° 1.63±0.14 R🜨

References

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  1. ^ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008. Retrieved 30 August 2022.
  2. ^ a b c d e f 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. ^ a b c d e f g h i Astudillo-Defru, N.; Cloutier, R.; et al. (April 2020). "A hot terrestrial planet orbiting the bright M dwarf L 168-9 unveiled by TESS". Astronomy & Astrophysics. 636: A58. arXiv:2001.09175. Bibcode:2020A&A...636A..58A. doi:10.1051/0004-6361/201937179. S2CID 210920549.
  4. ^ a b c Hobson, M. J.; Bouchy, F.; Lavie, B.; Lovis, C.; Adibekyan, V.; Prieto, C. Allende; Alibert, Y.; Barros, S. C. C.; Castro-González, A.; Cristiani, S.; D’Odorico, V.; Damasso, M.; Marcantonio, P. Di; Dumusque, X.; Ehrenreich, D. (2024-08-01). "Three super-Earths and a possible water world from TESS and ESPRESSO". Astronomy & Astrophysics. 688: A216. arXiv:2406.06278. doi:10.1051/0004-6361/202450505. ISSN 0004-6361.
  5. ^ "L 168-9". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 August 2022.
  6. ^ "List of ExoWorlds 2022". nameexoworlds.iau.org. IAU. 8 August 2022. Retrieved 27 August 2022.
  7. ^ "2022 Approved Names". nameexoworlds.iau.org. IAU. Retrieved 7 June 2023.
  8. ^ Rigby, Jane; Perrin, Marshall; McElwain, Michael; Kimble, Randy; Friedman, Scott; Lallo, Matt; Doyon, René; Feinberg, Lee; Ferruit, Pierre; Glasse, Alistair; Rieke, Marcia; et al. (April 2023). "The Science Performance of JWST as Characterized in Commissioning". Publications of the Astronomical Society of the Pacific. 135 (1046): 048001. arXiv:2207.05632. Bibcode:2023PASP..135d8001R. doi:10.1088/1538-3873/acb293.
  9. ^ Bouwman, Jeroen; Kendrew, Sarah; et al. (March 2023). "Spectroscopic Time Series Performance of the Mid-infrared Instrument on the JWST". Publications of the Astronomical Society of the Pacific. 135 (1045): 038002. arXiv:2211.16123. Bibcode:2023PASP..135c8002B. doi:10.1088/1538-3873/acbc49.
  10. ^ Alam, Munazza K.; et al. (2025). "JWST COMPASS: The First Near- to Mid-infrared Transmission Spectrum of the Hot Super-Earth L 168-9 b". The Astronomical Journal. 169 (1) 15. arXiv:2411.03154. Bibcode:2025AJ....169...15A. doi:10.3847/1538-3881/ad8eb5.
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