HD 38529

HD 38529
Location of HD 38529 (circled in red)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Orion
HD 38529 A
Right ascension 05h 46m 34.91314s
Declination +01° 10′ 05.5029″
Apparent magnitude (V) +5.95
HD 38529 B
Right ascension 05h 46m 19.37663s
Declination +01° 12′ 47.2640″
Apparent magnitude (V) +13.35
Characteristics
HD 38529 A
Evolutionary stage subgiant
Spectral type G4IV
B−V color index 0.773
HD 38529 B
Evolutionary stage main sequence
Spectral type M3.0V
Astrometry
HD 38529 A
Radial velocity (Rv)30.19±0.12 km/s
Proper motion (μ) RA: −77.806 mas/yr
Dec.: −141.363 mas/yr
Parallax (π)23.5714±0.0422 mas
Distance138.4 ± 0.2 ly
(42.42 ± 0.08 pc)
Absolute magnitude (MV)+2.81
HD 38529 B
Radial velocity (Rv)30.94±0.43 km/s
Proper motion (μ) RA: −78.612 mas/yr
Dec.: −142.084 mas/yr
Parallax (π)23.7139±0.0168 mas
Distance137.54 ± 0.10 ly
(42.17 ± 0.03 pc)
Absolute magnitude (MV)+10.23[citation needed]
Details
HD 38529 A
Mass1.479±0.037 M☉
Radius2.678±0.026 R☉
Luminosity6.16±0.15 L☉
Surface gravity (log g)3.83±0.06 cgs
Temperature5619±44 K
Metallicity [Fe/H]0.38±0.03 dex
Rotation37.0±0.4 d
Rotational velocity (v sin i)3.20±0.50 km/s
Age3.07±0.39 Gyr
HD 38529 B
Mass0.494 M☉
Radius0.496 R☉
Luminosity0.033 L☉
Surface gravity (log g)4.74 cgs
Temperature3,487 K
Metallicity [Fe/H]0.39 dex
Rotational velocity (v sin i)17 km/s
Other designations
RAG 1, WDS J05466+0110AB
HD 38529 A: BD+01°1126, HIP 27253, HR 1988, WDS J05466+0110A
HD 38529 B: WDS J05466+0110B, LP 598-99, 2MASS J05461937+0112471
Database references
SIMBADA
B
Exoplanet Archivedata

HD 38529 (138 G. Orionis) 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, though it has also been classified as a main sequence dwarf of type G4V and a borderline giant star of type G8III/IV. It is about 48% more massive than the Sun.

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. Its orbit is probably mildly misaligned with the planetary orbits, by 21−45°.

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. 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.

In 2003, a massive superjovian HD 38529 c was found orbiting at 3.68 AU with a minimum mass of 12.7 Jupiter masses. 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.

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. The possible third planet was refuted after additional radial velocity measurements were collected. Subsequent astrometric studies have found masses for HD 38529 c ranging from just 10.4 MJ to 18 MJ, with the most recent value as of 2025 being 12.9 MJ.

The HD 38529 A planetary system
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. Wide binary stars such as HD 38529 AB have been shown to be vulnerable to disruption by galactic tides and perturbations by passing stars.

See also

Notes

  1. ↑ HD 38529 b: Henry et al. (2013)
    HD 38529 c: Feng et al. (2025)
    Debris disk: Xuan et al. (2020)

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 7 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.
  3. 1 2 3 4 5 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.
  4. 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.
  5. 1 2 3 4 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.
  6. 1 2 3 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.
  7. 1 2 3 4 5 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.
  8. 1 2 3 4 5 6 7 8 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.
  9. 1 2 3 4 5 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.
  10. ↑ "WDS J05466+0110AB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-07.
  11. ↑ "HD 38529". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-09.
  12. ↑ "HD 38529 B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-09.
  13. ↑ 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.
  14. 1 2 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.
  15. ↑ 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.
  16. ↑ 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.
  17. 1 2 3 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.
  18. ↑ 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.
  19. ↑ 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.
  20. ↑ 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.
  21. 1 2 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. 539 (4): 3180–3200. arXiv:2412.14542. doi:10.1093/mnras/staf689.
  22. ↑ 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.