| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Piscis Austrinus |
| Right ascension | 21h 38m 08.40391s[1] |
| Declination | −31° 44′ 14.9407″[1] |
| Apparent magnitude (V) | 8.56[2] |
| Characteristics | |
| Spectral type | F7 V[3] |
| B−Vcolor index | 0.546±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.30±0.30[2] km/s |
| Proper motion (μ) | RA: +21.914[1]mas/yr Dec.: −82.166[1]mas/yr |
| Parallax (π) | 10.7826±0.1029 mas[1] |
| Distance | 302 ± 3 ly (92.7 ± 0.9 pc) |
| Absolute magnitude (MV) | 3.42[2] |
| Details[4] | |
| Mass | 1.329±0.003 M☉ |
| Radius | 1.59±0.04 R☉ |
| Luminosity | 3.52±0.01 L☉ |
| Surface gravity (log g) | 4.15±0.02 cgs |
| Temperature | 6,276±41 K |
| Metallicity [Fe/H] | 0.21[5] dex |
| Rotational velocity (v sin i) | 4.06[5] km/s |
| Age | 2.8±0.2 Gyr |
| Other designations | |
| Samaya,CD−32° 16667,HD 205739,HIP 106824,SAO 213152,PPM 301636[6] | |
| Database references | |
| SIMBAD | data |
HD 205739 is a yellow-white huedstar in the southernconstellation ofPiscis Austrinus, positioned near the western constellation boundary withMicroscopium. It has the proper nameSāmaya, which was selected in theNameExoWorlds campaign bySri Lanka, during the 100th anniversary of theIAU. Sāmaya (සාමය) meanspeace in theSinhalese language.[7][8]
With anapparent visual magnitude of 8.56,[2] this star requires a small telescope to view. It is located at a distance of approximately 302 light years from theSun based onstellar parallax, and is drifting further away with aradial velocity of +9 km/s[2] This star has anabsolute magnitude of 3.42.[2]
HD 205739 is an ordinaryF-type main-sequence star with astellar classification of F7 V.[3] This indicates that, like the Sun, it is generating energy throughcorehydrogen fusion. The star is 2.8[4] billion years old with aninactive chromosphere[9] and is spinning with aprojected rotational velocity of 4 km/s.[5] It has 1.3 times themass of the Sun and 1.6 times theSun's radius.[4] The abundance of iron is 60% greater than in the Sun, suggesting a highermetallicity.[5] The star is radiating 3.5 times theluminosity of the Sun from itsphotosphere at aneffective temperature of 6,276 K.[4]
AJupiter-likeplanet has been detected in an eccentric orbit around this star viaDoppler spectroscopy. The eccentricity of 0.27 indicates that the orbit carries the body from0.65 AU out to1.14 AU betweenperiastron andapastron. The maximum surface temperature of the planet is ~400 K, varying by 100 K over the course of an orbit. There is a data trend in the results which may point to an additional companion further from its star, but this will require a longer observation period to validate.[9]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Samagiya | ≥1.37 MJ | 0.896 | 279.8±0.1 | 0.27±0.07 | — | — |
