HD 121056
The spectrum of HD 121056 presents as an evolved K-type giant star with a stellar classification of K0 III. It is presently ascending the red-giant branch, having exhausted the supply of hydrogen at its core. The star is about 5.5 billion years old and is spinning with a projected rotational velocity of 2.4 km/s. HD 121056’s concentration of heavy elements is similar to the Sun, with a metallicity Fe/H index of 0.020±0.031, although the star is enriched in lighter rock-forming elements like magnesium and aluminum. It has 1.6 times the mass of the Sun and has expanded to 5.72 times the Sun's radius. The star is radiating 15.8 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,867 K.
Planetary system
In 2014, two planets orbiting HD 121056 were discovered by the radial velocity method, and were confirmed a few months later. The orbits of these planets are stable on astronomical timescales, although the periods are not in orbital resonance. In 2022, the inclination and true mass of HD 121056 c were measured via astrometry.
The planetary system configuration is favorable for direct imaging of exoplanets in the near future, being included in the top ten easiest targets in 2018.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 1.568+0.071 −0.072 MJ |
0.482 −0.010 |
88.9±0.1 | 0.063 −0.032 |
— | — |
| c | 6.937 −0.518 MJ |
6.032 −0.362 |
3,923.7 −330.2 |
0.356 −0.085 |
89.863 −24.730° |
— |
References
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- ^ Hojjatpanah, S.; et al. (2019). "Catalog for the ESPRESSO blind radial velocity exoplanet survey". Astronomy & Astrophysics. 629: A80. arXiv:1908.04627. Bibcode:2019A&A...629A..80H. doi:10.1051/0004-6361/201834729. S2CID 199552090.
- ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- ^ Jones, M. I.; et al. (2015). "A planetary system and a highly eccentric brown dwarf around the giant stars HIP 67851 and HIP 97233". Astronomy & Astrophysics. 573: A3. arXiv:1409.7429. Bibcode:2015A&A...573A...3J. doi:10.1051/0004-6361/201424771. S2CID 53638707.
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- ^ Sousa, S. G.; et al. (2018). "SWEET-Cat updated". Astronomy & Astrophysics. 620: A58. arXiv:1810.08108. Bibcode:2018A&A...620A..58S. doi:10.1051/0004-6361/201833350. S2CID 119374557.
- ^ Soto, M. G.; et al. (2021). "SPECIES. II. Stellar parameters of the EXPRESS giant star sample". Astronomy and Astrophysics. 647: A157. arXiv:2009.03371. Bibcode:2021A&A...647A.157S. doi:10.1051/0004-6361/202039357. S2CID 221534230.
- ^ "HD 121056". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-05-13.
- ^ Wittenmyer, Robert A.; et al. (2015). "The Pan-Pacific Planet Search. Ii. Confirmation of a Two-Planet System Around Hd 121056". The Astrophysical Journal. 800 (1): 74. arXiv:1412.6889. Bibcode:2015ApJ...800...74W. doi:10.1088/0004-637X/800/1/74. S2CID 53684180.
- ^ Kane, Stephen R.; et al. (2019). "Predicting multiple planet stability and habitable zone companions in the TESS era". Monthly Notices of the Royal Astronomical Society. 485 (4): 4703–4725. arXiv:1901.11297. Bibcode:2019MNRAS.485.4703A. doi:10.1093/mnras/stz345.
- ^ Saillenfest, M.; et al. (2019). "Secular spin-axis dynamics of exoplanets". Astronomy & Astrophysics. 623: A4. arXiv:1901.02831. Bibcode:2019A&A...623A...4S. doi:10.1051/0004-6361/201834344. S2CID 119073661.
- ^ Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series. 262 (21): 21. arXiv:2208.12720. Bibcode:2022ApJS..262...21F. doi:10.3847/1538-4365/ac7e57. S2CID 251864022.
- ^ Martinache, Frantz; Ireland, Michael J. (2018). "Kernel-nulling for a robust direct interferometric detection of extrasolar planets". Astronomy & Astrophysics. 619: A87. arXiv:1802.06252. Bibcode:2018A&A...619A..87M. doi:10.1051/0004-6361/201832847. S2CID 118882482.
