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] |
Distance | 173.8 ± 0.3 ly (53.29 ± 0.09 pc) |
Details | |
Mass | 1.09 ± 0.02[4] M☉ |
Radius | 1.13 ± 0.03[4] R☉ |
Luminosity | 1.28 ± 0.01[4] L☉ |
Surface gravity (log g) | 4.37 ± 0.03[4] cgs |
Temperature | 5773 ± 55[4] K |
Age | 4.1 ± 1.4[4] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
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.
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]
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° |
— |