| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Orion |
| Right ascension | 06h 12m 00.567s[1] |
| Declination | +06° 46′ 59.06″[1] |
| Apparent magnitude (V) | 6.85[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G4V[3] |
| B−V color index | 0.642±0.007[2] |
| Astrometry | |
| Radial velocity (Rv) | −53.52±0.14[4] km/s |
| Proper motion (μ) | RA: 197.247 mas/yr[1] Dec.: −254.867 mas/yr[1] |
| Parallax (π) | 40.9764 ± 0.0240 mas[1] |
| Distance | 79.60 ± 0.05 ly (24.40 ± 0.01 pc) |
| Absolute magnitude (MV) | 5.03±0.06[3] |
| Details | |
| Mass | 0.92±0.02[5] M☉ |
| Radius | 0.94[5] R☉ |
| Luminosity | 0.918±0.012[5] L☉ |
| Surface gravity (log g) | 4.44±0.01[6] cgs |
| Temperature | 5,758±5 K[6] 5,765±17[5] K |
| Metallicity [Fe/H] | −0.096±0.005 dex[6] −0.10±0.02[5] dex |
| Rotation | 16.9 d[7] |
| Rotational velocity (v sin i) | 1.83±0.11[6] km/s |
| Age | 5.51±0.71 Gyr[6] 5.5±0.2[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 42618 is a well-studied[7] star with an exoplanetary companion in the equatorial constellation of Orion. With an apparent visual magnitude of 6.85[2] it is too faint to be readily visible to the naked eye. This system is located at a distance of 79.6 light years from the Sun based on parallax measurements. It has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.321″ per year.[9] HD 42618 is drifting closer with a radial velocity of −53.5[4] km/s and is predicted to come as near as 42.6 light-years in around 297,000 years.[2]
The stellar classification of HD 42618 is G4V,[3] which shows it to be an ordinary G-type main-sequence star. It is considered a close solar analog, which means the physical properties of the star are particularly similar to those of the Sun.[10] Seismic model indicates the star is older and more evolved than the Sun with an age of about 5.5 billion years.[5] It is spinning with a low projected rotational velocity of 1.8 km/s,[6] with the rotation rate being consistent with the star's low activity level.[11] The star has 92% of the mass of the Sun and 94% of the Sun's radius. The surface metallicity is lower than in the Sun,[5] with the abundance patterns being consistent with a solar-type star.[11] HD 42618 is radiating 92% of the luminosity of the Sun from its photosphere at an effective temperature of 5,765 K.[5]
In 2016, the discovery of a candidate exoplanet companion orbiting HD 42618 was announced. Designated HD 42618 b, it was found using the radial velocity method which showed a periodicity of 149.6 days. The orbital elements have the planet orbiting at a distance of 0.55 AU from the host star with an orbital eccentricity (ovalness) of 0.2 and a Neptune-like mass. A second signal with a period of 388 days was detected, but this is unconfirmed and may be false. A 4,850 day signal is likely the result of star's magnetic activity cycle.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 14.4+2.5 −2.4 M🜨 |
0.554±0.011 | 149.61+0.37 −0.34 |
0.19+0.15 −0.12 |
— | — |
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