HD 66428 is a G-type main sequence star located approximately 174 light-years away in the constellation of Monoceros. This star is similar to the Sun with an apparent magnitude of 8.25, an effective temperature of 5705 ± 27 K and a solar luminosity 1.28. Its absolute magnitude is 11.1 while its U-V color index is 0.71. It is considered an inactive star and it is metal-rich ([Fe/H] = 0.310).[2][3][5] This star has a precise mass of 1.14552 solar masses. This precision comes from the Corot mission that measured asteroseismology.

HD 66428
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Monoceros
Right ascension 08h 03m 28.66767s[1]
Declination −01° 09′ 45.7581″[1]
Apparent magnitude (V) 8.25[2]
Characteristics
Spectral type G5[3]
Astrometry
Radial velocity (Rv)44.26±0.13[1] km/s
Proper motion (μ) RA: −65.766±0.029 mas/yr[1]
Dec.: −206.999±0.019 mas/yr[1]
Parallax (π)18.7661 ± 0.0312 mas[1]
Distance173.8 ± 0.3 ly
(53.29 ± 0.09 pc)
Details
Mass1.09 ± 0.02[4] M
Radius1.13 ± 0.03[4] R
Luminosity1.28 ± 0.01[4] L
Surface gravity (log g)4.37 ± 0.03[4] cgs
Temperature5773 ± 55[4] K
Age4.1 ± 1.4[4] Gyr
Other designations
BD−00°1891, HIP 39417, LTT 3038, SAO 135426
Database references
SIMBADdata

Planetary system

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In July 2006, the discovery of the extrasolar planet HD 66428 b was published in the Astrophysical Journal. It was found from observations at the W. M. Keck Observatory using the radial velocity method. It has a minimum mass of more than 3 times that of Jupiter and orbits at a distance of 3.47 AU away from the star.[2][6]

In 2015 a refined orbit was determined which led to the discovery of a linear trend in the radial velocities indicating a more distant companion of unknown character,[6] which was determined to be a gas giant planet HD 66428 c or brown dwarf in 2021.[7] In 2022, the inclination and true mass of both planets were measured via astrometry. The orbital period and mass of planet c were found to be significantly lower than the previous higher-error estimates, showing it to be planetary mass and not a brown dwarf.[8]

The HD 66428 planetary system[8]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(years)
Eccentricity Inclination Radius
b 10.946+2.442
−3.845
 MJ
3.395+0.141
−0.157
6.214+0.015
−0.016
0.471±0.012 16.639+10.121
−2.959
°
c 1.764+3.404
−0.041
 MJ
9.408+1.945
−1.267
28.690+9.206
−5.348
0.207+0.097
−0.098
93.938+57.003
−55.476
°

See also

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References

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  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 Butler, R. P.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701. S2CID 119067572.
  3. ^ a b Kashyap, V.L.; et al. (2008). "Extrasolar Giant Planets and X-Ray Activity". Astrophysical Journal. 687 (2): 1339–1356. arXiv:0807.1308. Bibcode:2008ApJ...687.1339K. doi:10.1086/591922. S2CID 17515630.
  4. ^ a b c d e f Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
  5. ^ Sousa, S.G.; et al. (2008). "Spectroscopic parameters for 451 stars in the HARPS GTO planet search program". Astronomy and Astrophysics. 487 (1): 373–381. arXiv:0805.4826. Bibcode:2008A&A...487..373S. doi:10.1051/0004-6361:200809698. S2CID 18173201.
  6. ^ a b Feng, Y. Katherina; et al. (2015). "The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-period Planets". The Astrophysical Journal. 800 (1). 22. arXiv:1501.00633. Bibcode:2015ApJ...800...22F. doi:10.1088/0004-637X/800/1/22. S2CID 56390823.
  7. ^ Rosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C.; Petigura, Erik A.; Knutson, Heather A.; Behmard, Aida; Chontos, Ashley; Crepp, Justin R.; Crossfield, Ian J. M.; Dalba, Paul A.; Fischer, Debra A.; Henry, Gregory W.; Kane, Stephen R.; Kosiarek, Molly; Marcy, Geoffrey W.; Rubenzahl, Ryan A.; Weiss, Lauren M.; Wright, Jason T. (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
  8. ^ a b 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.
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