Astronomy:HD 38529

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Short description: Binary star system in the constellation Orion
HD 38529
Location of HD 38529 (circled in red)
Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000.0      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}}
Constellation Orion[1]
HD 38529 A
Right ascension  05h 46m 34.91314s[2]
Declination +01° 10′ 05.5029″[2]
Apparent magnitude (V) +5.95[3]
HD 38529 B
Right ascension  05h 46m 19.37663s[4]
Declination +01° 12′ 47.2640″[4]
Apparent magnitude (V) +13.35[5]
Characteristics
HD 38529 A
Evolutionary stage subgiant[2]
Spectral type G4IV[3]
B−V color index 0.773[3]
HD 38529 B
Evolutionary stage main sequence[6]
Spectral type M3.0V[5]
Astrometry
HD 38529 A
Radial velocity (Rv)30.19±0.12[2] km/s
Proper motion (μ) RA: −77.806[2] mas/yr
Dec.: −141.363[2] mas/yr
Parallax (π)23.5714 ± 0.0422[2] mas
Distance138.4 ± 0.2 ly
(42.42 ± 0.08 pc)
Absolute magnitude (MV)+2.81[3]
HD 38529 B
Radial velocity (Rv)30.94±0.43[4] km/s
Proper motion (μ) RA: −78.612 mas/yr
Dec.: −142.084 mas/yr
Parallax (π)23.7139 ± 0.0168[4] mas
Distance137.54 ± 0.10 ly
(42.17 ± 0.03 pc)
Details
HD 38529 A
Mass1.479±0.037[7] M☉
Radius2.678±0.026[7] R☉
Luminosity6.16±0.15[7] L☉
Surface gravity (log g)3.83±0.06[8] cgs
Temperature5619±44[8] K
Metallicity [Fe/H]0.38±0.03[8] dex
Rotation37.0±0.4 d[8]
Rotational velocity (v sin i)3.20±0.50[8] km/s
Age3.07±0.39[7] Gyr
HD 38529 B
Mass0.494[9] M☉
Radius0.496[9] R☉
Luminosity0.033[9] L☉
Surface gravity (log g)4.74[9] cgs
Temperature3,487[9] K
Rotational velocity (v sin i)17[6] km/s
Other designations
RAG 1, WDS J05466+0110AB[10]
HD 38529 A: BD+01°1126, HIP 27253, HR 1988, WDS J05466+0110A[11]
HD 38529 B: WDS J05466+0110B, LP 598-99, 2MASS J05461937+0112471[12]
Database references
SIMBADA
B
Exoplanet Archivedata

HD 38529 (138 G. Orionis)[13] 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,[14] though it has also been classified as a main sequence dwarf of type G4V[5] and a borderline giant star of type G8III/IV.[15] It is about 48% more massive than the Sun.[7]

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.[16] Its orbit is probably mildly misaligned with the planetary orbits, by 21−45°.[17]

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.[14] 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.[8]

In 2003, a massive superjovian HD 38529 c was found orbiting at 3.68 AU with a minimum mass of 12.7 Jupiter masses.[3] 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.[18]

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.[19] The possible third planet was refuted after additional radial velocity measurements were collected.[8] Subsequent astrometric studies have found masses for HD 38529 c ranging from just 10.4 MJ[20] to 18 MJ,[17] with the most recent value as of 2025 being 12.9 MJ.[21]

The HD 38529 A planetary system[lower-alpha 1]
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.[5] Wide binary stars such as HD 38529 AB have been shown to be vulnerable to disruption by galactic tides and perturbations by passing stars.[22]

See also

Notes

  1. ↑ HD 38529 b: Henry et al. (2013)[8]
    HD 38529 c: Feng et al. (2025)[21]
    Debris disk: Xuan et al. (2020)[17]

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R  Constellation record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 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. doi:10.1086/367889. Bibcode: 2003ApJ...586.1394F. 
  4. ↑ 4.0 4.1 4.2 4.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  5. ↑ 5.0 5.1 5.2 5.3 Raghavan, Deepak et al. (2006). "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems". The Astrophysical Journal 646 (1): 523–542. doi:10.1086/504823. Bibcode: 2006ApJ...646..523R. 
  6. ↑ 6.0 6.1 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. doi:10.3847/1538-4357/ab1fe9. Bibcode: 2019ApJ...878..134K. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Ball, Warrick H.; Chaplin, William J.; Nielsen, Martin B.; González-Cuesta, Lucia; Mathur, Savita; Santos, Ângela R G.; García, Rafael; Buzasi, Derek et al. (2020). "Robust asteroseismic properties of the bright planet host HD 38529". Monthly Notices of the Royal Astronomical Society 499 (4): 6084–6093. doi:10.1093/mnras/staa3190. Bibcode: 2020MNRAS.499.6084B. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 Henry, Gregory W. et al. (2013). "Host Star Properties and Transit Exclusion for the HD 38529 Planetary System". The Astrophysical Journal 768 (2): 155. doi:10.1088/0004-637X/768/2/155. Bibcode: 2013ApJ...768..155H. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 Stassun, Keivan G. et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S. 
  10. ↑ "WDS J05466+0110AB". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=WDS+J05466%2B0110AB. 
  11. ↑ "HD 38529". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+38529. 
  12. ↑ "HD 38529 B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+38529+B. 
  13. ↑ Gould, Benjamin Apthorp (1879). "Uranometria Argentina catalog of bright southern stars". Resultados del Observatorio Nacional Argentino en Cordoba (Buenos Aires) 1. Bibcode: 1879RNAO....1.....G. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F135%2Fcatalog. Retrieved 2012-05-08. 
  14. ↑ 14.0 14.1 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. doi:10.1086/320224. Bibcode: 2001ApJ...551.1107F. 
  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. doi:10.1086/529027. Bibcode: 2008ApJ...677..630H. 
  17. ↑ 17.0 17.1 17.2 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. doi:10.1093/mnras/staa3155. Bibcode: 2020MNRAS.499.5059X. 
  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. doi:10.1051/0004-6361:20054611. Bibcode: 2006A&A...449..699R. 
  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. doi:10.1088/0004-6256/139/5/1844. Bibcode: 2010AJ....139.1844B. 
  20. ↑ Feng, Fabo et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series 262 (21): 21. doi:10.3847/1538-4365/ac7e57. Bibcode: 2022ApJS..262...21F. 
  21. ↑ 21.0 21.1 Feng, Fabo 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. 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. doi:10.1051/0004-6361/201731229. Bibcode: 2017A&A...608A.116C. https://www.aanda.org/articles/aa/full_html/2017/12/aa31229-17/aa31229-17.html. 

Coordinates: Sky map 05h 46m 34.9120s, +01° 10′ 05.496″