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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

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. 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.

Planetary system

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, and has been observed as one of its first targets.

A newer study refined the planetary parameters of L 168-9 b. The newer research found a lower mass of 4.07 M_E and a higher radius of 1.63 R_🜨. These parameters imply a lower density of 5.18 g/cm, in contrast to the previous value of 9.6 g/cm. 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.

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.

References

1. "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008. Retrieved 30 August 2022.
2. ^ 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. ^ 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. ^ 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.

v t e Constellation of Tucana
List of stars in Tucana Tucana in Chinese astronomy
Stars	Bayer α β β β γ δ ε ζ η θ ι κ λ λ μ ν π ρ Variable DS HR 8829 HD 4308 5980 7199 (Emiw) 215497 221287 (Poerava) Other AB7 Gliese 54 HV 2112 HV 11417 HV 11423 L 168-9 PMMR 62 SMC 018136
Exoplanets DS Tucanae Ab HD 4308 b HD 7199 b (Hairu) HD 215497 b c HD 219077 b HD 221287 b (Pipitea)
Star clusters	NGC 121 152 176 220 222 231 241 256 265 267 269 290 294 299 306 330 339 346 361 362 371 376 395 411 416 419 422 456 458 460 465 Other ξ (47)
Nebulae E0102
Galaxies	NGC 53 360 406 432 434 440 466 484 7329 Other ESO 148-2 ISOHDFS 27 Tucana Dwarf Small Magellanic Cloud (partly in Hydrus)
Category

• Tucana
• M-type main-sequence stars
• Planetary systems with one confirmed planet
• Durchmusterung objects
• Gliese and GJ objects
• Hipparcos objects
• TESS Objects of Interest
• Stars with proper names