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HD 38529

HD 38529 (138 G. Orionis)[12] is a binary star system approximately 138 light-years away in the constellation of Orion.

HD 38529 A

HD 38529 A is a yellow subgiant star of spectral type G4IV,[13] though it has also been classified as a main sequence dwarf of type G4V[4] and a borderline giant star of type G8III/IV.[14] It is about 48% more massive than the Sun.[5]

Two substellar companions are known in orbit around this star, including one with a mass near the deuterium fusion limit that is often used as the dividing line between giant planets and brown dwarfs. There is a debris disk located at least 86 astronomical units from the star.[15] Its orbit is probably mildly misaligned with the planetary orbits, by 21−45°.[16]

Planetary system

In 2001, the planet HD 38529 b was discovered orbiting the star HD 38529 A by Debra Fischer and collaborators who detected it using the Doppler spectroscopy technique.[13] It has a mass at least 78% that of Jupiter and orbits very close to the star, just beyond the distance limit for hot Jupiters. It does not transit the star.[6]

In 2003, a massive superjovian HD 38529 c was found orbiting at 3.68 AU with a minimum mass of 12.7 Jupiter masses.[2] Astrometric measurements from the Hipparcos satellite gave a best fit inclination of 160° and a true mass 37 times that of Jupiter, turning this planet into a brown dwarf.[17]

Further study of the system using Hubble Space Telescope astrometry revised the mass of HD 38529 c downwards to 17.7 Jupiter masses and suggested the presence of an additional planet, orbiting in the gap between HD 38529 b and c.[18] The possible third planet was refuted after additional radial velocity measurements were collected.[6] Subsequent astrometric studies have found masses for HD 38529 c ranging from just 10.4 MJ[19] to 18 MJ,[16] with the most recent value as of 2025 being 12.9 MJ.[20]

The HD 38529 A planetary system[6][20][16]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥0.8047±0.0139 MJ 0.1278±0.0006 14.30978±0.00033 0.259±0.016 — —
c 12.93+0.70
−0.49 MJ 		3.604+0.043
−0.042 		2127.8+3.3
−3.2 		0.3507+0.0057
−0.0051 		104.2+8.9
−11° 		—
Debris disk 46+38
−27–208±54 AU 		71+10
−7° 		—

HD 38529 B

HD 38529 B is a common proper motion stellar companion to HD 38529 A at a projected distance of about ~12000 astronomical units. The star is a red dwarf of spectral type M3.0V.[4] Wide binary stars such as HD 38529 AB have been shown to be vulnerable to disruption by galactic tides and perturbations by passing stars.[21]

See also

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 Fischer, Debra A.; et al. (2003). "A Planetary Companion to HD 40979 and Additional Planets Orbiting HD 12661 and HD 38529". The Astrophysical Journal. 586 (2): 1394–1408. Bibcode:2003ApJ...586.1394F. doi:10.1086/367889.
  3. ^ 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.
  4. ^ a b c d Raghavan, Deepak; et al. (2006). "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems". The Astrophysical Journal. 646 (1): 523–542. arXiv:astro-ph/0603836. Bibcode:2006ApJ...646..523R. doi:10.1086/504823.
  5. ^ a b c d e Ball, Warrick H.; Chaplin, William J.; Nielsen, Martin B.; González-Cuesta, Lucia; Mathur, Savita; Santos, Ângela R G.; García, Rafael; Buzasi, Derek; Mosser, Benoît; Deal, Morgan; Stokholm, Amalie; Mosumgaard, Jakob Rørsted; Silva Aguirre, Victor; Nsamba, Benard; Campante, Tiago; Cunha, Margarida S.; Ong, Joel; Basu, Sarbani; Örtel, Sibel; Çelik Orhan, Z.; Yıldız, Mutlu; Stassun, Keivan; Kane, Stephen R.; Huber, Daniel (2020). "Robust asteroseismic properties of the bright planet host HD 38529". Monthly Notices of the Royal Astronomical Society. 499 (4): 6084–6093. arXiv:2010.07323. Bibcode:2020MNRAS.499.6084B. doi:10.1093/mnras/staa3190. S2CID 222378164.
  6. ^ a b c d e f g h Henry, Gregory W.; et al. (2013). "Host Star Properties and Transit Exclusion for the HD 38529 Planetary System". The Astrophysical Journal. 768 (2). 155. arXiv:1303.4735. Bibcode:2013ApJ...768..155H. doi:10.1088/0004-637X/768/2/155.
  7. ^ a b c d e Stassun, Keivan G.; et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467.
  8. ^ a b Kuznetsov, M. K.; Del Burgo, C.; Pavlenko, Ya. V.; Frith, J. (2019). "Characterization of a Sample of Southern M Dwarfs Using Harps and X-shooter Spectra". The Astrophysical Journal. 878 (2): 134. Bibcode:2019ApJ...878..134K. doi:10.3847/1538-4357/ab1fe9.
  9. ^ "WDS J05466+0110AB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-07.
  10. ^ "HD 38529". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-09.
  11. ^ "HD 38529 B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-09.
  12. ^ Gould, Benjamin Apthorp (1879). "Uranometria Argentina catalog of bright southern stars". Resultados del Observatorio Nacional Argentino en Cordoba. 1. Buenos Aires. Bibcode:1879RNAO....1.....G. Retrieved 2012-05-08.
  13. ^ a b Fischer, Debra A.; et al. (2001). "Planetary Companions to HD 12661, HD 92788, and HD 38529 and Variations in Keplerian Residuals of Extrasolar Planets". The Astrophysical Journal. 551 (2): 1107–1118. Bibcode:2001ApJ...551.1107F. doi:10.1086/320224.
  14. ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  15. ^ Hillenbrand, Lynne A.; et al. (2008). "The Complete Census of 70 μm-bright Debris Disks within "the Formation and Evolution of Planetary Systems" Spitzer Legacy Survey of Sun-like Stars". The Astrophysical Journal. 677 (1): 630–656. arXiv:0801.0163. Bibcode:2008ApJ...677..630H. doi:10.1086/529027.
  16. ^ a b c Xuan, Jerry W.; Kennedy, Grant M.; Wyatt, Mark C.; Yelverton, Ben (2020). "Mutual inclinations between giant planets and their debris discs in HD 113337 and HD 38529". Monthly Notices of the Royal Astronomical Society. 499 (4): 5059–5074. arXiv:2010.02961. Bibcode:2020MNRAS.499.5059X. doi:10.1093/mnras/staa3155. S2CID 222177269.
  17. ^ Reffert, S.; Quirrenbach, A. (2006). "Hipparcos astrometric orbits for two brown dwarf companions: HD 38529 and HD 168443". Astronomy and Astrophysics. 449 (2): 699–702. Bibcode:2006A&A...449..699R. doi:10.1051/0004-6361:20054611. hdl:1887/7483.
  18. ^ Benedict, G. Fritz; et al. (2010). "The Mass of HD 38529c from Hubble Space Telescope Astrometry and High-precision Radial Velocities". The Astronomical Journal. 139 (5): 1844–1856. arXiv:1003.0421. Bibcode:2010AJ....139.1844B. doi:10.1088/0004-6256/139/5/1844.
  19. ^ 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.
  20. ^ a b Feng, Fabo; Xiao, Guang-Yao; et al. (April 2025). "Lessons learned from the detection of wide companions by radial velocity and astrometry". Monthly Notices of the Royal Astronomical Society. arXiv:2412.14542.
  21. ^ Correa-Otto, J. A.; Gil-Hutton, R. A. (2017). "Galactic perturbations on the population of wide binary stars with exoplanets". Astronomy and Astrophysics. 608. A116. arXiv:1710.00766. Bibcode:2017A&A...608A.116C. doi:10.1051/0004-6361/201731229. hdl:11336/41265.