HD 121056
Observation data
Epoch J2000      Equinox J2000
Constellation Centaurus
Right ascension 13h 53m 52.06131s[1]
Declination −35° 18′ 51.6918″[1]
Apparent magnitude (V) 6.17[2]
Characteristics
Evolutionary stage giant star
Spectral type K0III[3]
B−V color index 1.01[4]
Astrometry
Radial velocity (Rv)5.60±0.13[1] km/s
Proper motion (μ) RA: −295.304±0.040 mas/yr[1]
Dec.: −68.458±0.058 mas/yr[1]
Parallax (π)15.6261 ± 0.0418 mas[1]
Distance208.7 ± 0.6 ly
(64.0 ± 0.2 pc)
Absolute magnitude (MV)+2.08[5]
Details
Mass1.60±0.18[6] M☉
Radius5.72[7] R☉
Luminosity15.8[7] L☉
Surface gravity (log g)3.261±0.105[2] cgs
Temperature4867±49[2] K
Metallicity[Mg/H] 0.286±0.05 dex[2]
Metallicity [Fe/H]0.020±0.031[2] dex
Rotational velocity (v sin i)2.38±0.51[2] km/s
Age5.46[7] Gyr
Other designations
CD−34 9223, Gaia DR2 6169943210465504384, GJ 532.1, HIP 67851, HR 5224, TYC 7287-1874-1, 2MASS J13535209-3518517[8]
Database references
SIMBADdata

HD 121056, also known as HIP 67851, is a K-type giant star 209 light-years away in the constellation of Centaurus. Its surface temperature is 4867±49 K. 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.[2]

Planetary system

In 2014, two planets orbiting HD 121056 were discovered by the radial velocity method,[4] and were confirmed a few months later.[9] The orbits of these planets are stable on astronomical timescales,[10] although the periods are not in orbital resonance.[11] In 2022, the inclination and true mass of HD 121056 c were measured via astrometry.[12]

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.[13]

The HD 121056 planetary system[12]
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+0.009
−0.010 		88.9±0.1 0.063+0.031
−0.032 		— —
c 6.937+2.045
−0.518 MJ 		6.032+0.651
−0.362 		3923.7+617.5
−330.2 		0.356+0.112
−0.085 		89.863+28.378
−24.730° 		—

References

  1. ^ a b c d e 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.
  2. ^ a b c d e f g 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 & Astrophysics. 629: A80. arXiv:1908.04627. Bibcode:2019A&A...629A..80H. doi:10.1051/0004-6361/201834729. S2CID 199552090.
  3. ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. ^ a b Jones, M. I.; Jenkins, J. S.; Rojo, P.; Melo, C. H. F.; Bluhm, P. (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.
  5. ^ Anderson, E.; Francis, Ch. (2012-05-01). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. ISSN 1063-7737. S2CID 119257644.
  6. ^ Sousa, S. G.; Adibekyan, V.; Delgado-Mena, E.; Santos, N. C.; Andreasen, D. T.; Ferreira, A. C. S.; Tsantaki, M.; Barros, S. C. C.; Demangeon, O.; Israelian, G.; Faria, J. P.; Figueira, P.; Mortier, A.; Brandão, I.; Montalto, M.; Rojas-Ayala, B.; Santerne, A. (2018). "SWEET-Cat updated". Astronomy & Astrophysics. 620: A58. arXiv:1810.08108. Bibcode:2018A&A...620A..58S. doi:10.1051/0004-6361/201833350. S2CID 119374557.
  7. ^ a b c Soto, M. G.; Jones, M. I.; Jenkins, J. S. (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.
  8. ^ "HD 121056". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-05-13.
  9. ^ Wittenmyer, Robert A.; Wang, Liang; Liu, Fan; Horner, Jonathan; Endl, Michael; Johnson, John Asher; Tinney, C. G.; Carter, B. D. (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.
  10. ^ Kane, Stephen R.; Horner, Jonathan; Maddison, Sarah T.; Agnew, Matthew T. (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, doi:10.1093/mnras/stz345
  11. ^ Saillenfest, M.; Laskar, J.; Boué, G. (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.
  12. ^ a b 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.
  13. ^ 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
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