HD 29399 is a binary star in the constellation Reticulum. With an apparent visual magnitude of 5.78, it is visible to the naked eye under good viewing conditions. From its parallax measured by the Gaia, it is located at a distance of 144 light-years (44 parsecs) from Earth.
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Reticulum |
| Right ascension | 04h 33m 33.949s[1] |
| Declination | −62° 49′ 25.24″[1] |
| Apparent magnitude (V) | 5.780[2] |
| Characteristics | |
| Spectral type | K1III[3] |
| U−B color index | +2.111[4] |
| B−V color index | +0.332[4] |
| Astrometry | |
| Radial velocity (Rv) | 31.56±0.13[1] km/s |
| Proper motion (μ) | RA: −117.58±0.04[1] mas/yr Dec.: −18.73±0.04[1] mas/yr |
| Parallax (π) | 22.7240 ± 0.0339 mas[1] |
| Distance | 143.5 ± 0.2 ly (44.01 ± 0.07 pc) |
| Details | |
| Mass | 1.17±0.10[5] M☉ |
| Radius | 4.47±0.02[5] R☉ |
| Luminosity | 10.04±0.20[5] L☉ |
| Surface gravity (log g) | 3.25±0.13[5] cgs |
| Temperature | 4,845±52[5] K |
| Metallicity [Fe/H] | 0.14±0.03[5] dex |
| Rotational velocity (v sin i) | 2.48[6] km/s |
| Age | 6.20±0.5[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This star is a K-type giant with an spectral type of K1III. Its magnitude 9.2 companion is located at a separation of 31.9 arcseconds.[8] In 2022, a gas giant planet was discovered via the radial velocity method orbiting the primary star.[5]
Star system
editHD 29399 is a K-type giant star with a spectral type of K1III,[3] which indicates it is an evolved star that has ceased hydrogen fusion in its nucleus and left the main sequence. Its main properties were inferred with high precision from an asteroseismology model created with photometric data acquired by the TESS spacecraft, which observed HD 29399 almost continuously for one year during its primary mission. HD 29399 has a mass of 1.17 M☉, radius of 4.47 R☉, and an age of about 6.2 billion years. It is shining with a bolometric luminosity of about 10 L☉, and an effective temperature of 4,850 K. Its metallicity, the proportion of elements other than hydrogen and helium, is slightly higher than the solar value, with an iron abundance 40% greater than the Sun's.[5]
HD 29399 is part probably of a binary system with a magnitude 9.2 star at an angular separation of 31.9 arcseconds.[8] Astrometric data obtained by the Gaia spacecraft have confirmed that both stars have similar proper motions and distances from Earth. This star has an estimated mass of 0.79 M☉, luminosity of 0.35 L☉, and effective temperature of 4,900 K.[1]
Planetary system
editThis star was included in the Pan-Pacific Planet Search, which used the Anglo-Australian Telescope to search for exoplanets around giant stars in the southern hemisphere. A 2017 study, analyzing data from HD 29399 obtained in this survey, discovered a 765-day periodic signal in the star's radial velocity, which could be caused by an orbiting planet. However, the authors attributed this signal to a stellar magnetic cycle, reporting a periodicity in the star's light curve and a possible correlation between the radial velocity and the equivalent width of the Hα line, which both point to stellar activity being the cause of the signal.[9] A 2022 study, using additional observations by the CORALIE spectrograph at the Leonhard Euler Telescope, confirmed the presence a 900-day signal in the star's radial velocity, and did not find evidence to support an stellar activity origin for this signal, concluding that a planet is the most likely explanation.[5]
The planet, designated HD 29399 b, is a gas giant with a minimum mass of 1.6 MJ. Since the radial velocity method used in its discovery measures only the star's motion along the line of sight to Earth, the orbital inclination is unconstrained, and the planet's true mass cannot be determined. HD 29399 b takes 893 days to complete an orbit and is located at a distance of 1.91 AU from its star, which is far enough for its orbit to be unaffected by tidal forces at any point of the star's evolution. Its orbital eccentricity is small and the data are consistent with a circular orbit.[5]
The orbital solution for HD 29399 includes a linear trend, indicating the existence of an additional body in the system. The current data are consistent with a second giant planet with a period of the order of decades, although nothing can be said with certainty about such object yet.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.57±0.11 MJ | 1.913±0.008 | 892.7±5.9 | 0.05±0.05 | — | — |
References
edit- ^ a b c d e f g 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.
- ^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H, ISSN 0004-6361
- ^ a b Houk, Nancy (1975), "Michigan catalogue of two-dimensional spectral types for the HD stars", University of Michigan Catalogue of Two-Dimensional Spectral Types for the Hd Stars. Volume I. Declinations -90_ to -53_Ƒ0, 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H
- ^ a b Paunzen, E. (May 2022), "Catalogue of stars measured in the Geneva seven-colour photometric system", Astronomy & Astrophysics, 661: A89, arXiv:2111.04810, Bibcode:2022A&A...661A..89P, doi:10.1051/0004-6361/202142355, eISSN 1432-0746, ISSN 0004-6361
- ^ a b c d e f g h i j k l m Pezzotti, C.; Ottoni, G.; Buldgen, G.; Lyttle, A.; Eggenberger, P.; Udry, S.; Ségransan, D.; Mayor, M.; Lovis, C.; Marmier, M.; Miglio, A.; Elsworth, Y.; Davies, G. R.; Ball, W. H. (2022), "CORALIE radial-velocity search for companions around evolved stars (CASCADES). III. A new Jupiter host-star: In-depth analysis of HD 29399 using TESS data", Astronomy and Astrophysics, 657: A89, arXiv:2201.01553, Bibcode:2022A&A...657A..89P, doi:10.1051/0004-6361/202040080, S2CID 242974999
- ^ Hojjatpanah, S.; Figueira, P.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Delgado-Mena, E.; Alibert, Y.; Cristiani, S.; González Hernández, J. I.; Lanza, A. F.; Di Marcantonio, P.; Martins, J. H. C.; Micela, G.; Molaro, P.; Neves, V.; Oshagh, M.; Pepe, F.; Poretti, E.; Rojas-Ayala, B.; Rebolo, R.; Suárez Mascareño, A.; Zapatero Osorio, M. R. (2019), "Catalog for the ESPRESSO blind radial velocity exoplanet survey", Astronomy and Astrophysics, 629: A80, arXiv:1908.04627, Bibcode:2019A&A...629A..80H, doi:10.1051/0004-6361/201834729, S2CID 199552090
- ^ "HD 29399". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-01-28.
- ^ a b Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976
- ^ Wittenmyer, Robert A.; Jones, M. I.; Zhao, Jinglin; Marshall, J. P.; Butler, R. P.; Tinney, C. G.; Wang, Liang; Johnson, John Asher (2017), "The Pan-Pacific Planet Search. VI. Giant Planets Orbiting HD 86950 and HD 222076", The Astronomical Journal, 153 (2): 51, arXiv:1611.07648, Bibcode:2017AJ....153...51W, doi:10.3847/1538-3881/153/2/51, S2CID 119446216