HD 219134

Star HD 219134 (circled) lies just off the "W" shape of the constellation Cassiopeia.
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
Right ascension 23h 13m 16.97496s[1]
Declination +57° 10′ 06.0838″[1]
Apparent magnitude (V) 5.574[2]
Characteristics
Spectral type K3V[3]
U−B color index +0.902[2]
B−V color index +0.983[2]
Variable type Suspected[4]
Astrometry
Radial velocity (Rv)−18.68±0.12[1] km/s
Proper motion (μ) RA: 2074.414 mas/yr[1]
Dec.: 294.452 mas/yr[1]
Parallax (π)152.8640 ± 0.0494 mas[1]
Distance21.336 ± 0.007 ly
(6.542 ± 0.002 pc)
Absolute magnitude (MV)6.46[5]
Details
Mass0.81±0.03[6] M☉
Radius0.778±0.005[6] R☉
Luminosity0.2646[6] L☉
Surface gravity (log g)4.567±0.018[6] cgs
Temperature4699[6] K
Metallicity [Fe/H]+0.11 (± 0.04)[6] dex
Rotational velocity (v sin i)6.94[7] km/s
Age11.0[6] Gyr
Other designations
BD+56 2966, FK5 875, GCTP 5616.00, Gl 892, HD 219134, HIP 114622, HR 8832, LFT 1767, LHS 71, LTT 16826, SAO 35236.[8]
Database references
SIMBADdata

HD 219134 (also known as Gliese 892 or HR 8832) is a main-sequence star in the constellation of Cassiopeia. It is smaller and less luminous than the Sun, with a spectral class of K3V, which makes it an orange-hued star. HD 219134 is relatively close to our system, with an estimated distance of 21.34 light years. This star is close to the limit of apparent magnitude that can still be seen by the unaided eye. The limit is considered to be magnitude 6 for most observers. This star has a magnitude 9.4 optical companion at an angular separation of 106.6 arcseconds.[9]

Planetary system

HD 219134 has a system of six known exoplanets. The innermost planet, HD 219134 b, is a rocky super-Earth based on size (1.6 times the size of Earth), and density (6.4 grams per cubic cm).[10][11] This and three additional exoplanets; one super-Earth (designated c and later found to be rocky as well), one Neptunian world (d), and one Jovian world (e); were deduced using HARPS-N radial velocity data by Motalebi et al. in 2015.[12][13] Two months later, Vogt et al. published a paper on this system which found a 6-planet solution, with planets b, c & d corresponding to those in Motalebi et al., f & g being new planets, and h corresponding to Motalebi's e but with different, and more accurate, estimated parameters.[14][15]

A number of independent studies have been done regarding the planetary system of HD 219134, with some of their results conflicting with each other. As of March 2017, the star is known to have at least 5 planets, with two of them (HD 219134 b and c) known to be transiting, rocky super-Earths.[16][17] While a 2016 study suggested that the radial velocity signal corresponding to planet f might be caused by stellar activity,[15] it has been confirmed by subsequent studies in 2017[16] and 2021.[18] Planet g has not been reported by subsequent studies, and a 2020 study did not find evidence of its claimed 94-day period, but instead found a period of 192 days.[19]

The HD 219134 planetary system[14][15][16]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 4.74±0.19 M🜨 0.03876±0.00047 3.092926±0.000010 0 (fixed) 85.05±0.09° 1.602±0.055 R🜨
c 4.36±0.22 M🜨 0.06530±0.00080 6.76458±0.00033 0.062±0.039 87.28±0.10° 1.511±0.047 R🜨
f >7.30±0.40 M🜨 0.1463±0.0018 22.717±0.015 0.148±0.047 — —
d >16.17±0.64 M🜨 0.2370±0.0030 46.859±0.028 0.138±0.025 — —
g >11±1 M🜨 0.3753±0.0004 94.2±0.2 0 — —
h (e)[20] >98 M🜨 3.11±0.04 2100.6±2.9 0.06±0.04 — —

Habitable Zone

The conservative habitable zone (CHZ) of HD 219134 is estimated to extend from 0.516 to 0.948 AU.[21][22] None of the planets orbiting the star are confirmed to orbit inside the habitable zone.[23] The planet candidate HD 219134 g may orbit slightly interior to the inner edge of the habitable zone based on its initially published parameters,[14] or may orbit within the habitable zone based on a more recent estimated orbital period of 192 days and semi-major axis of 0.603 AU.[19] This planet is significantly more massive than Earth and therefore it likely retains a dense atmosphere, comparable to the Solar System's ice giants.

References

  1. 1 2 3 4 5 6 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. 1 2 3 Oja, T. (August 1986), "UBV photometry of stars whose positions are accurately known. III", Astronomy and Astrophysics Supplement Series, 65 (2): 405–409, Bibcode:1986A&AS...65..405O.
  3. ↑ Frasca, A.; et al. (December 2009), "REM near-IR and optical photometric monitoring of pre-main sequence stars in Orion. Rotation periods and starspot parameters", Astronomy and Astrophysics, 508 (3): 1313–1330, arXiv:0911.0760, Bibcode:2009A&A...508.1313F, doi:10.1051/0004-6361/200913327, S2CID 118361131.
  4. ↑ Kukarkin, B. V.; et al. (1981), "Nachrichtenblatt der Vereinigung der Sternfreunde e.V. (Catalogue of suspected variable stars)", Nachrichtenblatt der Vereinigung der Sternfreunde E.V. (1981), Moscow: Academy of Sciences USSR Shternberg: 0, Bibcode:1981CSV...C......0K.
  5. ↑ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  6. 1 2 3 4 5 6 7 "HD 219134". exoplanetarchive.ipac.caltech.edu. Retrieved 2017-12-24.
  7. ↑ Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter" (PDF), Astronomy and Astrophysics, 520: A79, arXiv:1002.4391, Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725, S2CID 43455849, archived from the original (PDF) on 2017-09-22, retrieved 2018-11-04.
  8. ↑ "HR 8832". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-04-08.
  9. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  10. ↑ "PIA19832: Location of Nearest Rocky Exoplanet Known". NASA. 30 July 2015. Retrieved 30 July 2015.
  11. ↑ Chou, Felicia; Clavin, Whitney (30 July 2015). "NASA's Spitzer Confirms Closest Rocky Exoplanet". NASA. Retrieved 31 July 2015.
  12. ↑ Motalebi, F.; et al. (December 2015). "The HARPS-N Rocky Planet Search. I. HD 219134 b: A transiting rocky planet in a multi-planet system at 6.5 pc from the Sun". Astronomy & Astrophysics. 584: A72. arXiv:1507.08532. Bibcode:2015A&A...584A..72M. doi:10.1051/0004-6361/201526822. S2CID 45652878.
  13. ↑ "Cassiopeia's Hidden Gem". Harvard. 30 July 2015. Retrieved 30 July 2015.
  14. 1 2 3 Vogt, Steven S.; et al. (November 2015). "Six Planets Orbiting HD 219134". The Astrophysical Journal. 814 (1): 12. arXiv:1509.07912. Bibcode:2015ApJ...814...12V. doi:10.1088/0004-637X/814/1/12. S2CID 45438051.
  15. 1 2 3 Johnson, Marshall C.; et al. (April 2016). "A 12-year Activity Cycle for the Nearby Planet Host Star HD 219134". The Astrophysical Journal. 821 (2): 74. arXiv:1602.05200. Bibcode:2016ApJ...821...74J. doi:10.3847/0004-637X/821/2/74. S2CID 118651905.
  16. 1 2 3 Gillon, Michaël; et al. (2017). "Two massive rocky planets transiting a K-dwarf 6.5 parsecs away". Nature Astronomy. 1 (3). 0056. arXiv:1703.01430. Bibcode:2017NatAs...1E..56G. doi:10.1038/s41550-017-0056. S2CID 56075932.
  17. ↑ "Back Alley Astronomy: HD 219134 Scorecard: 5 planets, 2 transiting". 18 April 2017.
  18. ↑ Rosenthal, Lee J.; et al. (2021). "The California Legacy Survey. I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades". The Astrophysical Journal Supplement Series. 255 (1): 8. arXiv:2105.11583. Bibcode:2021ApJS..255....8R. doi:10.3847/1538-4365/abe23c. S2CID 235186973.
  19. 1 2 Hirsch, Lea A.; et al. (2021), "Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc", The Astronomical Journal, 161 (3): 134, arXiv:2012.09190, Bibcode:2021AJ....161..134H, doi:10.3847/1538-3881/abd639, S2CID 229297873.
  20. ↑ Van Zandt, Judah; et al. (2023), "TESS-Keck Survey. XIV. Two Giant Exoplanets from the Distant Giants Survey", The Astronomical Journal, 165 (2): 60, arXiv:2209.06958, Bibcode:2023AJ....165...60V, doi:10.3847/1538-3881/aca6ef, S2CID 252280288
  21. ↑ "HD 219134 g". ExoKyoto.
  22. ↑ "HD 219134". hzgallery.org.
  23. ↑ Dietrich, Jeremy; Apai, Dániel; Malhotra, Renu (2022). "An Integrative Analysis of the HD 219134 Planetary System and the Inner solar system: Extending DYNAMITE with Enhanced Orbital Dynamical Stability Criteria". The Astronomical Journal. 163 (2): 88. arXiv:2112.05337. Bibcode:2022AJ....163...88D. doi:10.3847/1538-3881/ac4166. S2CID 245117944.
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