| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Grus[1] |
| Right ascension | 21h 57m 19.84754s[2] |
| Declination | −37° 45′ 49.0480″[2] |
| Apparent magnitude (V) | 7.47[1] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | G1/3V[3] |
| B−Vcolor index | 0.568±0.009[1] |
| Variable type | Stable[4] |
| Astrometry | |
| Radial velocity (Rv) | 5.575±0.0004[5] km/s |
| Proper motion (μ) | RA: 101.032mas/yr[2] Dec.: −118.842mas/yr[2] |
| Parallax (π) | 22.2688±0.0304 mas[2] |
| Distance | 146.5 ± 0.2 ly (44.91 ± 0.06 pc) |
| Absolute magnitude (MV) | 4.26[4] |
| Absolute bolometric magnitude (Mbol) | 4.06[4] |
| Details | |
| Mass | 1.16±0.02[6] M☉ |
| Radius | 1.17±0.03[6] R☉ |
| Luminosity | 1.76±0.05[6] L☉ |
| Surface gravity (log g) | 4.36±0.03[6] cgs |
| Temperature | 6,143±47[6] K |
| Metallicity [Fe/H] | 0.08[7] dex |
| Rotational velocity (v sin i) | 3.688[6] km/s |
| Age | 2.3±0.9 Gyr[6] 1.325±1.007[7] Gyr |
| Other designations | |
| Itonda,CD−38° 14804,HD 208487,HIP 108375,SAO 213432,PPM 302029[8] | |
| Database references | |
| SIMBAD | data |
HD 208487 is astar with an orbitingexoplanet in theconstellation ofGrus. Based onparallax measurements, it is located at a distance of 146.5 light years from the Sun. Theabsolute magnitude of HD 208487 is 4.26,[4] but at that distance theapparent visual magnitude is 7.47,[1] which is too faint to be viewed with the naked eye. The system is drifting further away with aradial velocity of 5.6 km/s.[5] It is a member of thethin disk population.[7]
Thespectrum of HD 208487 presents as an ordinaryG-type main-sequence star with astellar classification of G1/3V.[3] It is a relatively young star, with age estimates of 1–2 billion years, and is spinning with aprojected rotational velocity of 3.7 km/s.[7][6] The star has 16% greater mass and a 17% larger radius than the Sun.[6] The abundance of iron, a measure of the star'smetallicity, is similar to the Sun.[7] It is radiating 176% of the luminosity of the Sun from itsphotosphere at aneffective temperature of 6,143 K.[6] The level ofmagnetic activity in thechromosphere is low.[4]
The star HD 208487 is namedItonda and the exoplanetMintome. The names were selected in theNameExoWorlds campaign byGabon, during the 100th anniversary of theIAU. Itonda, in theMyene tongue, corresponds to all that is beautiful. Mintome, in theFang tongue, is a mythical land where a brotherhood of brave men live.[9][10]
There is one known planet orbiting the star HD 208487, which is designatedHD 208487 b.[4] It has a mass at least half that ofJupiter and is located in aneccentric 130-day orbit.
The discovery of a second planet in the system was announced on 13 September 2005, by P.C. Gregory. The discovery was made usingBayesian analysis of the radial velocity dataset to determine the planetary parameters.[11] However, further analysis revealed that an alternative two-planet solution for the HD 208487 system was possible, with a planet in a 28-day orbit instead of the 908-day orbit postulated, and it was concluded that activity on the star is more likely to be responsible for the residuals to the one-planet solution than the presence of a second planet.[12]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Mintome | >0.520 ± 0.082 MJ | 0.51 ± 0.02 | 130.08 ± 0.51 | 0.24 ± 0.16 | — | — |
