| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13h 32m 25.55543s[1] |
| Declination | –47° 16′ 16.9091″[1] |
| Apparent magnitude (V) | 7.17[2] |
| Characteristics | |
| Spectral type | G0 V[3] |
| B−Vcolor index | 0.603±0.010[2] |
| Astrometry | |
| Radial velocity (Rv) | +1.60±0.76[2] km/s |
| Proper motion (μ) | RA: +24.87[1]mas/yr Dec.: −125.01[1]mas/yr |
| Parallax (π) | 26.34±0.60 mas[1] |
| Distance | 124 ± 3 ly (38.0 ± 0.9 pc) |
| Absolute magnitude (MV) | 4.27[2] |
| Details[4] | |
| Mass | 1.10±0.02 M☉ |
| Radius | 1.17±0.04 R☉ |
| Luminosity | 1.6±0.1 L☉ |
| Surface gravity (log g) | 4.34±0.03 cgs |
| Temperature | 6,019±50 K |
| Metallicity [Fe/H] | +0.03±0.01[5] dex |
| Rotational velocity (v sin i) | 3.67[6] km/s |
| Age | 4.0±1.3 Gyr |
| Other designations | |
| Dofida,CD−46° 8708,GC 18290,HD 117618,HIP 66047,SAO 224228[7] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 117618, namedDofida by theIAU,[8] is a single,[9] yellow-huedstar in the southernconstellation ofCentaurus. With anapparent visual magnitude of 7.17,[2] it is too faint to be visible to the naked eyes of a typical observer. The distance to this star, as determined from its annualparallax shift of26.34±0.60 mas as seen from Earth's orbit,[1] is about 124 light years. It is moving further away with a heliocentricradial velocity of around +1.6 km/s.[2]
This star is similar to theSun, being aG-type main-sequence star with astellar classification of G0 V.[3] It is about 10% more massive and 17% larger than the Sun, with an estimated age of roughly four billion years[4] and aprojected rotational velocity of 3.67 km/s.[6] The star is radiating 1.6 times theSun's luminosity from itsphotosphere at aneffective temperature of 6,019 K.[4]
HD 117618, and its planet HD 117618b, were chosen as part of the 2019NameExoWorlds campaign organised by theInternational Astronomical Union, which assigned each country a star and planet to be named. HD 117618 was assigned toIndonesia. The winning proposal named the star "Dofida" meaningour star inNias language, and its planet "Noifasui" meaningrevolve around in Nias language (derived from the wordifasui, meaningto revolve around, andno, indicating that the action occurred in the past and continued to the present time).[8]
In 2005, theAnglo-Australian Planet Search program announced the discovery of a low-mass planet in orbit around HD 117618. This object was found through measurements of radial velocity variation, which were larger than those produced by the intrinsic jitter of the host star. The bestKeplerian fit to the data gave aperiodicity of 25.8 days with aneccentricity of around 0.37 and asemimajor axis of0.17 AU. Thelower bound on the object's mass was estimated to be0.16 MJ.[10] These values were subsequently refined, as shown in the table below.[11]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Noifasui | >0.178 ± 0.021 MJ | 0.176 ± 0.010 | 25.827±0.019 | 0.42 ± 0.17 | — | — |
