HD 38529

HD 38529 A/B
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Orion
Right ascension 05h 46m 34.91s[1]
Declination +01° 10′ 05.5″[1]
Apparent magnitude (V) +5.94 / +13.35
Characteristics
Spectral type G4IV / M3.0V
U−B color index ? / ?
B−V color index 0.773 / 0.46
Variable type none / ?
Astrometry
Radial velocity (Rv)+28.9 km/s
Proper motion (μ) RA: -79.12 ± 0.48[1] mas/yr
Dec.: -141.84 ± 0.35[1] mas/yr
Parallax (π)25.46 ± 0.40[1] mas
Distance128 ± 2 ly
(39.3 ± 0.6 pc)
Absolute magnitude (MV)+2.81 / +10.23
Details
Mass1.48[2] / ? M☉
Radius2.82 / ? R☉
Luminosity5.90 / ? L☉
Temperature5370 / ? K
Metallicity0.29 ± 0.05 [Fe/H]
Rotation34.5 / ?
Age~3700 million years
Other designations
138 G. Orionis, HR 1988, BD+01°1126, HIP 27253, SAO 113119
Database references
SIMBADdata

HD 38529 (138 G. Orionis) is a binary star approximately 128 light-years away in the constellation of Orion.

HD 38529 A

HD 38529 A is a yellow subgiant star, which has also been classified as a main sequence dwarf of spectral type G4V. It is about 40% more massive than our Sun. Two substellar companions are known in orbit around this star, including one with a mass above 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.[3]

Planetary system

In 2002, the planet HD 38529 b was discovered orbiting the star HD 38529 A by Debra Fischer who used Doppler spectroscopy.[4] It has mass 78% that of Jupiter and orbits very close to the star, just beyond the distance limit for hot Jupiters. One year later, a massive superjovian HD 38529 c was found orbiting at 3.68 AU with a minimum mass of 12.7 Jupiter masses.[5] 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.[6] 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.[2] The possible third planet was refuted after additional radial velocity measurements were collected.[7]

The HD 38529 A planetary system[7]
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 16.76 ± 0.11 MJ 3.594 ± 0.018 2133.54 ± 3.31 0.3472 ± 0.0057 — —
Debris disk >86 AU — —

HD 38529 B

HD 38529 B is a common proper motion stellar companion to HD 38529 A at a projected distance of about 12042 AU. The star is a red dwarf of spectral type M3.0V.[8]

See also

References

  1. 1 2 3 4 5 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  2. 1 2 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.
  3. ↑ 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.
  4. ↑ 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.
  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.
  6. ↑ 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.
  7. 1 2 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.
  8. ↑ 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.

External links

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


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