| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pisces[1] |
| Right ascension | 00h 44m 41.2003s[2] |
| Declination | +20° 26′ 56.138″[2] |
| Apparent magnitude (V) | 8.70[1] |
| Characteristics | |
| Evolutionary stage | subgiant[3][2] |
| Spectral type | G5V[4] |
| B−Vcolor index | +0.771±0.021[1] |
| Astrometry | |
| Radial velocity (Rv) | −14.20±0.09[1] km/s |
| Proper motion (μ) | RA: +122.100[2]mas/yr Dec.: −124.204[2]mas/yr |
| Parallax (π) | 12.3036±0.0195 mas[2] |
| Distance | 265.1 ± 0.4 ly (81.3 ± 0.1 pc) |
| Absolute magnitude (MV) | 4.28[1] |
| Details[5] | |
| 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[1] dex |
| Rotational velocity (v sin i) | 5.6[6] km/s |
| Age | 6.3±1.0 Gyr |
| Other designations | |
| BD+19°117,HD 4203,HIP 3502,SAO 74235[7] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 4203 is a singlestar in theequatorialconstellation ofPisces, near the northern constellation border withAndromeda. It has a yellow hue and is too faint to be viewed with the naked eye, having anapparent visual magnitude of 8.70.[1] The distance to this object is 265 light years based onparallax,[2] but it is drifting closer to the Sun with aradial velocity of −14 km/s.[1]
This object is an ordinaryG-type subgiant star with astellar classification of G5V. It isphotometrically-stable star with an inactivechromosphere, and has a much higher than normalmetallicity.[4] The star is roughly 6.3 billion years old and is spinning with aprojected rotational velocity of 5.6 km/s.[6] It has 12% moremass than the Sun and a 35% greaterradius. HD 4203 is radiating 1.68 times theluminosity of the Sun from itsphotosphere at aneffective temperature of 5,666 K.[5]
Radial velocity observations of this star during 2000–2001 found a variability that suggesting an orbited sub-stellar companion, designated component 'b'.[4] Additional observations led to a refinedorbital period of 432 days with a relatively higheccentricity of 0.52 for agas giant companion.[8] 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.[9]
| 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 | — | — |
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