HD 46375
Star in the constellation Monoceros
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HD 46375 is double star[9] with an exoplanetary companion in the equatorial constellation of Monoceros. It presents as an 8th-magnitude star with an apparent visual magnitude of 7.91,[1] which is too dim to be readily visible to the naked eye. The system is located at a distance of 96.5 light-years from the Sun based on parallax measurements,[2] but is slowly drifting closer with a radial velocity of −1 km/s.[2] The common proper motion stellar companion, designated HD 46375 B, has a linear projected separation of 346±13 AU.[9]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Monoceros[1] |
| Right ascension | 06h 33m 12.62259s[2] |
| Declination | +05° 27′ 46.5278″[2] |
| Apparent magnitude (V) | 7.91[1] |
| Characteristics | |
| Spectral type | G9V[3] + M0V[4] |
| B−V color index | 0.860[1] |
| Variable type | Constant[5] |
| Astrometry | |
| Radial velocity (Rv) | −1.07±0.20[2] km/s |
| Proper motion (μ) | RA: +111.477[2] mas/yr Dec.: –96.918[2] mas/yr |
| Parallax (π) | 33.8088±0.0435 mas[2] |
| Distance | 96.5 ± 0.1 ly (29.58 ± 0.04 pc) |
| Absolute magnitude (MV) | 5.20[1] |
| Details | |
| A | |
| Mass | 0.91±0.01[6] M☉ |
| Radius | 1.01±0.01[6] R☉ |
| Luminosity | 0.77±0.01[6] L☉ |
| Surface gravity (log g) | 4.38±0.01[6] cgs |
| Temperature | 5,379±19[6] K |
| Metallicity [Fe/H] | +0.27±0.06[3] dex |
| Rotation | 42+9 −7[7] |
| Rotational velocity (v sin i) | 0.86[8] km/s |
| Age | 2.6±0.8 Gyr[7] 4.38±2.54 Gyr[3] 11.9±1.1[6] Gyr |
| B | |
| Mass | 0.576±0.013[9] M☉ |
| Temperature | 3,663±15[10] K |
| Metallicity [Fe/H] | 0.29±0.17[10] dex |
| Other designations | |
| BD+05°1295, HD 46375, HIP 31246, SAO 114040[11] | |
| Database references | |
| SIMBAD | data |
The primary component is a solar-type[7] star with a stellar classification of G9V,[3] matching a G-type main-sequence star. Age estimates for this star range from 2.6[7] up to 11.9[6] billion years. It is a chromospherically inactive star and is spinning slowly[5] with a projected rotational velocity of 0.86 km/s.[8] The absolute magnitude of this star places it one magnitude brighter than the equivalent for a zero age main sequence.[5] It has 91% of the mass and 101% of the radius of the Sun. The star is radiating 77%[6] of the luminosity of the Sun from its photosphere at an effective temperature of 3,663 K.[10]
This star has sometimes been classified as a member of the NGC 2244 star cluster in the Rosette Nebula, but in reality it just happens to lie in the foreground. The distance to the cluster is much greater, about 4500 light-years.
Planetary system
On March 29, 2000, the planet HD 46375 b with a minimum mass three quarters that of Saturn was discovered by Marcy, Butler, and Vogt in California, together with 79 Ceti b.[12][5] This planet was discovered using the "wobble method" or radial velocity method, which calculates the rate and shape of the stellar wobble caused by the revolving planet's gravity.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.226±0.019 MJ | 0.0398±0.0023 | 3.023573±0.000065 | 0.063±0.026 | — | — |