00h44m41.2021s, +20° 26′ 56.138″
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pisces |
| Right ascension | 00h44m 41.2003s[1] |
| Declination | +20° 26′ 56.1380″[1] |
| Apparent magnitude (V) | 8.70[2] |
| Characteristics | |
| Spectral type | G5V[3] |
| B−V color index | +0.771±0.021[2] |
| Astrometry | |
| Radial velocity (Rv) | −14.20±0.09[2] km/s |
| Proper motion (μ) | RA: +122.070±0.102[1] mas/yr Dec.: −124.192±0.062[1] mas/yr |
| Parallax (π) | 12.2595 ± 0.0538 mas[1] |
| Distance | 266 ± 1 ly (81.6 ± 0.4 pc) |
| Absolute magnitude (MV) | 4.28[2] |
| Details[4] | |
| Mass | 1.12±0.03 M☉ |
| Radius | 1.35±0.03 R☉ |
| Luminosity | 1.68±0.01 L☉ |
| Surface gravity (log g) | 4.22±0.03 cgs |
| Temperature | 5,666±43 K |
| Metallicity [Fe/H] | 0.34±0.01[2] dex |
| Rotational velocity (v sin i) | 5.6[5] km/s |
| Age | 6.3±1.0 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 4203 is a single star in the equatorial constellationofPisces, near the northern constellation border with Andromeda. It has a yellow hue and is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.70.[2] The distance to this object is 266 light years based on parallax,[1] but it is drifting closer to the Sun with a radial velocity of −14 km/s.[2]
This object is an ordinary G-type main-sequence star with a stellar classification of G5V. It is photometrically-stable star with an inactive chromosphere, and has a much higher than normal metallicity.[3] The star is roughly 6.3 billion years old and is spinning with a projected rotational velocity of 5.6 km/s.[5] It has 12% more mass than the Sun and a 35% greater radius. HD 4203 is radiating 1.68 times the luminosity of the Sun from its photosphere at an effective temperature of 5,666 K.[4]
Radial velocity observations of this star during 2000–2001 found a variability that suggesting an orbited sub-stellar companion, designated component 'b'.[3] Additional observations led to a refined orbital period of 432 days with a relatively high eccentricity of 0.52 for a gas giant companion.[7] The presence of a second companion was deduced from residuals in the data, then confirmed in 2014. However, the orbital elements for this companion, component 'c', are poorly constrained.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | > 1.164±0.067 MJ | 2.07±0.18 | 431.88±0.85 | 0.519±0.027 | — | — |
| c | > 2.17±0.52 MJ | — | 6,700±4,500 | 0.24±0.13 | — | — |
