HD 189276

HD 189276
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cygnus
Right ascension 19h 55m 55.37920s[1]
Declination +58° 50′ 45.4752″[1]
Apparent magnitude (V) 4.98[2]
Characteristics
Spectral type K4.5IIIa[3] or K5II-III[4]
B−V color index 1.584±0.011[2]
Astrometry
Radial velocity (Rv)+4.26±0.34[2] km/s
Proper motion (μ) RA: −8.953[1] mas/yr
Dec.: −20.206[1] mas/yr
Parallax (π)3.6680 ± 0.0864 mas[5]
Distance890 ± 20 ly
(273 ± 6 pc)
Absolute magnitude (MV)−2.25[2]
Details
Mass4.05±0.56[6] M☉
Radius178.11[7] R☉
Luminosity1,533±49[1] L☉
Surface gravity (log g)1.70[7] cgs
Temperature3,940+198
−30[1] K
Metallicity [Fe/H]−0.1[8] dex
Rotational velocity (v sin i)1.7[8] km/s
Other designations
BD+58°2013, FK5 3591, Gaia DR2 2235649675799721088, HD 189276, HIP 98073, HR 7633, SAO 32122, 2MASS J19555536+5850454[9]
Database references
SIMBADdata

HD 189276 is a single[4] star in the northern constellation Cygnus, positioned near the northern constellation border with Draco. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.98.[2] The star is located at a distance of approximately 820 light years from the Sun based on parallax, and it has an absolute magnitude of −2.25.[2] It is drifting further away with a radial velocity of +4 km/s.[2] The star has a high peculiar velocity of 38.5+1.8
−2.2 km/s and thus is a probable runaway star.[10]

This is an aging star on the red giant branch[7] with a stellar classification of K4.5IIIa.[3] With the supply of hydrogen at its exhausted, it has cooled and expanded to 178[7] times the girth of the Sun. This is an active star that appears to be approaching the tip of the red-giant branch. Interferometric measurements of the star suggest significant departures from symmetry.[7] HD 189276 has four[6] times the mass of the Sun and is radiating 1,533 times the Sun's luminosity from its bloated photosphere at an effective temperature of 3,940.[1]

  1. ^ a b c d e f g Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f g Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference perkins1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  5. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  6. ^ a b Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference Chiavassa2017 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Lèbre2006 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).