HD 195479
Am star in the constellation Delphinus
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HD 195479, also designated as HR 7839, is a solitary star located in the northern constellation Delphinus, the dolphin. It has an apparent magnitude of 6.20,[3] placing it near the limit for naked eye visibility, even under ideal conditions. The object is located relatively close at a distance of 288 light-years based on Gaia DR3 parallax measurements[2] and it is drifting closer with a heliocentric radial velocity of −40.1 km/s.[6] At its current distance, HD 195479's brightness is diminished by an interstellar extinction of 0.27 magnitudes[14] and it has an absolute magnitude of +1.53.[1]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Delphinus[1] |
| Right ascension | 20h 30m 58.26388s[2] |
| Declination | +20° 36′ 23.0762″[2] |
| Apparent magnitude (V) | 6.20±0.01[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | kA1 hA9 mF2[4] |
| U−B color index | +0.13[5] |
| B−V color index | +0.12[5] |
| Astrometry | |
| Radial velocity (Rv) | −40.1±1.6[6] km/s |
| Proper motion (μ) | RA: +95.633 mas/yr[2] Dec.: +58.78 mas/yr[2] |
| Parallax (π) | 11.3074±0.0337 mas[2] |
| Distance | 288.4 ± 0.9 ly (88.4 ± 0.3 pc) |
| Absolute magnitude (MV) | +1.53[1] |
| Details | |
| Mass | 2.05+0.38 −0.24[7] M☉ |
| Radius | 2.15±0.11[8] R☉ |
| Luminosity | 38.96+0.36 −0.42[2] L☉ |
| Surface gravity (log g) | 4.08[9] cgs |
| Temperature | 8,454[10] K |
| Metallicity [Fe/H] | −0.11[11] dex |
| Rotational velocity (v sin i) | 18.0±0.6[9] km/s |
| Age | 631[12] Myr |
| Other designations | |
| AG+20°2271, BD+20°4602, GC 28540, HD 195479, HIP 101213, HR 7839, SAO 88783, CCDM J20310+2036A, WDS J20310+2036A, TIC 379435621[13] | |
| Database references | |
| SIMBAD | data |
HD 195479 is an Am star with a stellar classification of kA1hA9mF2.[4] The notion indicates that it has the calcium K-lines of an A1 star, the hydrogen lines of an A9 star, and the metallic lines of a F2 star. It has 2.05 times the mass of the Sun[7] and 2.15 times the radius of the Sun.[8] It radiates 38.96 times the luminosity of the Sun[2] from its photosphere at an effective temperature of 8,454 K,[10] giving it white hue when viewed in the night sky. HD 195479 is deficient in iron, having an abundance 77.6% of the Sun's.[11] It is estimated to be 631 million years old[12] and it spins modestly with a projected rotational velocity of 18.0 km/s,[9] common for Am stars.
The star has two optical companions: a 12th magnitude star designated B located 5.7" away along a position angle of 88° and a 13th magnitude star designated C located 55.9" away along a position angle of 206°.[15] They were both observed by American astronomer Sherburne Wesley Burnham during the late 19th century.[16] B and C are both background stars that are far more distant than HD 195479.[17][18]