Astronomy:HD 66428
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Monoceros[1] |
| Right ascension | 08h 03m 28.66767s[2] |
| Declination | −01° 09′ 45.7581″[2] |
| Apparent magnitude (V) | 8.25[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G8IV(+G)[4] |
| Astrometry | |
| Radial velocity (Rv) | 44.26±0.13[2] km/s |
| Proper motion (μ) | RA: −65.766±0.029[2] mas/yr Dec.: −206.999±0.019[2] mas/yr |
| Parallax (π) | 18.7661 ± 0.0312[2] mas |
| Distance | 173.8 ± 0.3 ly (53.29 ± 0.09 pc) |
| Absolute magnitude (MV) | +4.56[1] |
| Details | |
| Mass | 1.09±0.02[5] M☉ |
| Radius | 1.13±0.03[5] R☉ |
| Luminosity | 1.28±0.01[5] L☉ |
| Surface gravity (log g) | 4.37±0.03[5] cgs |
| Temperature | 5,773±55[5] K |
| Age | 4.1±1.4[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 66428 is a G-type subgiant 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 5,705±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).[3][6][7] This star has a precise mass of 1.14552 solar masses. This precision comes from the Corot mission that measured asteroseismology.
Planetary system
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.[3][8]
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,[8] which was determined to be a gas giant planet HD 66428 c or brown dwarf in 2021.[9] 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.[10]
| 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
- List of extrasolar planets
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 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.
- ↑ 3.0 3.1 3.2 Butler, R. P. et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. doi:10.1086/504701. Bibcode: 2006ApJ...646..505B.
- ↑ 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.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Bonfanti, A. et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics 575: A18. doi:10.1051/0004-6361/201424951. Bibcode: 2015A&A...575A..18B.
- ↑ Kashyap, V.L. et al. (2008). "Extrasolar Giant Planets and X-Ray Activity". Astrophysical Journal 687 (2): 1339–1356. doi:10.1086/591922. Bibcode: 2008ApJ...687.1339K.
- ↑ 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. doi:10.1051/0004-6361:200809698. Bibcode: 2008A&A...487..373S.
- ↑ 8.0 8.1 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. doi:10.1088/0004-637X/800/1/22. Bibcode: 2015ApJ...800...22F.
- ↑ Rosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C. et al. (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. doi:10.3847/1538-4365/abe23c. Bibcode: 2021ApJS..255....8R.
- ↑ 10.0 10.1 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.
External links
- "Notes for star HD 66428". Extrasolar Planets Encyclopaedia. http://exoplanet.eu/star.php?st=HD+66428. Retrieved 2008-08-20.
Coordinates: 
08h 03m 28.6652s, −01° 09′ 45.752″
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