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Star in the constellation Microscopium From Wikipedia, the free encyclopedia
HD 203949 is a K-type giant star 257 light-years away in the constellation of Microscopium. Its surface temperature is 4618±113 K. It is either on the red giant branch fusing hydrogen in a shell around a helium core, or more likely a red clump star currently fusing helium in its core.[2] HD 203949 is enriched in heavy elements relative to the Sun, with a metallicity ([Fe/H]) of 0.17±0.07 dex. As is common for red giants, HD 203949 has an enhanced concentration of sodium and aluminium compared to iron.[2]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Microscopium |
Right ascension | 21h 26m 22.8745s[1] |
Declination | −37° 49′ 45.950″[1] |
Apparent magnitude (V) | 5.62±0.01[2] |
Characteristics | |
Evolutionary stage | giant |
Spectral type | K2III[3] |
Astrometry | |
Radial velocity (Rv) | −83.50±0.16[1] km/s |
Proper motion (μ) | RA: 168.257[1] mas/yr Dec.: −11.075[1] mas/yr |
Parallax (π) | 12.6806 ± 0.0577 mas[1] |
Distance | 257 ± 1 ly (78.9 ± 0.4 pc) |
Absolute magnitude (MV) | +1.10[4] |
Details[2] | |
Mass | 1.00±0.16 M☉ |
Radius | 10.30±0.51 R☉ |
Luminosity (bolometric) | 43.34±4.27 L☉ |
Surface gravity (log g) | 2.415±0.044 cgs |
Temperature | 4618±113 K |
Metallicity [Fe/H] | 0.17±0.07 dex |
Age | 7.29±3.06 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Multiplicity surveys did not find any stellar companions around HD 203949 as of 2019.[6]
In 2014, one planet orbiting HD 203949 was discovered by the radial velocity method.[7] The planet is highly unlikely to have survived the red giant stage of stellar evolution on the present orbit. It is likely to be recently scattered from a wider orbit.[2]
The planetary system configuration is favourable for direct imaging of exoplanets in the near future, and was included in the top ten easiest targets known by 2018.[8]
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
HIP 105854b | >8.2±0.2[note 1] MJ | 0.81±0.03 | 184.2±0.5 | 0.02±0.03 | — | — |
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