Astronomy:L 168-9
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[2] mas/yr Dec.: −127.782[2] mas/yr |
| Parallax (π) | 39.7113 ± 0.0244[2] mas |
| Distance | 82.13 ± 0.05 ly (25.18 ± 0.02 pc) |
| Details[4] | |
| Mass | 0.614±0.055 M☉ |
| Radius | 0.604±0.037 R☉ |
| Luminosity (bolometric) | 0.0723±0.0018 L☉ |
| Surface gravity (log g) | 4.84±0.08 cgs |
| Temperature | 3842±32 K |
| Metallicity [Fe/H] | 0.06±0.13 dex |
| Rotation | 29±2 d |
| Age | 3.0[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
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.[7] The approved names, proposed by a team from China, were announced in June 2023. L 168-9 is named Danfeng (丹凤) and its planet is named Qingluan (青鸾), after mythological birds of ancient China.[8]
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,[3] and has been observed as one of its first targets.[9][10]
A newer study refined the planetary parameters of L 168-9 b. The newer research found a lower mass of 4.07 M⊕ 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.[11]
| 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
- ↑ "Finding the constellation which contains given sky coordinates". 2 August 2008. http://djm.cc/constellation.html.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Astudillo-Defru, N. et al. (April 2020). "A hot terrestrial planet orbiting the bright M dwarf L 168-9 unveiled by TESS". Astronomy & Astrophysics 636: A58. doi:10.1051/0004-6361/201937179. Bibcode: 2020A&A...636A..58A.
- ↑ 4.0 4.1 4.2 Hobson, M. J.; Bouchy, F.; Lavie, B.; Lovis, C.; Adibekyan, V.; Prieto, C. Allende; Alibert, Y.; Barros, S. C. C. et al. (2024-08-01). "Three super-Earths and a possible water world from TESS and ESPRESSO" (in en). Astronomy & Astrophysics 688: A216. doi:10.1051/0004-6361/202450505. ISSN 0004-6361. Bibcode: 2024A&A...688A.216H. https://www.aanda.org/articles/aa/abs/2024/08/aa50505-24/aa50505-24.html.
- ↑ Engle, Scott G.; Guinan, Edward F. (2023). "Living with a Red Dwarf: The Rotation-Age Relationships of M Dwarfs". The Astrophysical Journal 954 (2): L50. doi:10.3847/2041-8213/acf472. Bibcode: 2023ApJ...954L..50E.
- ↑ "L 168-9". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=L+168-9.
- ↑ "List of ExoWorlds 2022". IAU. 8 August 2022. https://www.nameexoworlds.iau.org/2022exoworlds.
- ↑ "2022 Approved Names". IAU. https://www.nameexoworlds.iau.org/2022approved-names.
- ↑ Rigby, Jane et al. (April 2023). "The Science Performance of JWST as Characterized in Commissioning". Publications of the Astronomical Society of the Pacific 135 (1046): 048001. doi:10.1088/1538-3873/acb293. Bibcode: 2023PASP..135d8001R.
- ↑ Bouwman, Jeroen 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. doi:10.1088/1538-3873/acbc49. Bibcode: 2023PASP..135c8002B.
- ↑ 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). doi:10.3847/1538-3881/ad8eb5. Bibcode: 2025AJ....169...15A.
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