28 Vulpeculae

28 Vulpeculae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Vulpecula
Right ascension 20h 38m 31.9139s[1]
Declination +24° 06′ 57.4433″[1]
Apparent magnitude (V) 5.05[2]
Characteristics
Evolutionary stage Subgiant
Spectral type B5IV[3]
U−B color index −0.53[4]
B−V color index −0.14[4]
Astrometry
Radial velocity (Rv)−22.6±1.2[5] km/s
Proper motion (μ) RA: 10.317±0.273[1] mas/yr
Dec.: −6.940±0.253[1] mas/yr
Parallax (π)5.8740 ± 0.1760 mas[1]
Distance560 ± 20 ly
(170 ± 5 pc)
Absolute magnitude (MV)−0.96[5]
Details
Mass5.0[2] M☉
Luminosity713[2] L☉
Surface gravity (log g)3.77[6] cgs
Temperature15,200[2] K
Metallicity [Fe/H]+0.02±0.04[6] dex
Rotational velocity (v sin i)285[7] km/s
Other designations
28 Vul, BD+23°4084, HD 196740, HIP 101868, HR 7894, SAO 88945[8]
Database references
SIMBADdata

28 Vulpeculae is a single[9] star in the northern constellation of Vulpecula. It lies approximately 560 light years away and is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.047.[2] The star is moving closer to the Sun with a heliocentric radial velocity of −23 km/s, and may come as close as 198 light-years in 5.9 million years.[5]

This is a subgiant star with a spectral class of B5 IV,[3] indicating a hot massive star that has started to evolve away from the main sequence after exhausting it core hydrogen. It has been included in a list of the least variable stars observed with the Hipparcos satellite; its brightness varied by no more than 0.0005 magnitudes in the Hipparcos passband.[10] The star has five[2] times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 285 km/s.[7] It is radiating 713 times the Sun's luminosity from its photosphere at an effective temperature of 15,200 K.[2]

  1. ^ a b c d e Cite error: The named reference Gaia DR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f g Cite error: The named reference hohle was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference lesh was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference hr was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference xhip was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference wu was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference abt was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Simbad was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference adelman was invoked but never defined (see the help page).