HD 187086

HD 187086

A light curve for HD 187086, plotted from Hipparcos data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Telescopium
Right ascension 19h 50m 14.05959s[2]
Declination −47° 33′ 26.6014″[2]
Apparent magnitude (V) 5.95 - 6.07[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M1 III[5]
B−V color index +1.67[6]
Variable type suspected[3]
Astrometry
Radial velocity (Rv)−64±1[7] km/s
Proper motion (μ) RA: +9.424 mas/yr[2]
Dec.: −10.867 mas/yr[2]
Parallax (π)3.1998 ± 0.0655 mas[2]
Distance1,020 ± 20 ly
(313 ± 6 pc)
Absolute magnitude (MV)−0.80[8]
Details
Mass1.76±0.09[9] M☉
Radius111±6[10] R☉
Luminosity1,031±56[11] L☉
Surface gravity (log g)1.5±1[2] cgs
Temperature3,821±122[12] K
Metallicity [Fe/H]+0.24[2] dex
Other designations
69 G. Telescopii[13], NSV 12432, CD−47°13103, CPD−47°9366, GC 27427, HD 187086, HIP 95798, HR 7537, SAO 229887[14]
Database references
SIMBADdata

HD 187086, also known as HR 7537, is a probable astrometric binary[15] (87% chance[16]) located in the southern constellation Telescopium. It has an average apparent magnitude of 5.9, making it faintly visible to the naked eye. The star is located relatively far at a distance of 1,020 light years based on Gaia DR3 parallax measurements[2] but is rapidly drifting closer with a heliocentric radial velocity of −64 km/s.[7] At its current distance, HD 187086's brightness is diminished by 0.27 magnitudes due to interstellar dust.[17] It has an absolute magnitude of −0.8.[8]

The primary has a stellar classification of M1 III,[5] indicating that it is a red giant. It is currently on the asymptotic giant branch, fusing hydrogen and helium shells around an inert carbon core. It has 1.76 times the mass of the Sun[9] but it has expanded to 111 times the solar radius.[10] It radiates 1,031 times the luminosity of the Sun[11] from its enlarged photosphere at an effective temperature of 3,821 K,[12] giving it a red hue. HD 187086 is particularly metal enriched ([Fe/H] = +0.24).[2]

HD 187086 fluctuates between 5.95 and 6.07[3] and its variability was first noticed by P.M. Corben in 1971 after being listed as an ordinary M-type giant a year prior.[6][18] In 2002, Chris Koen and Laurent Eyer reported that the Hipparcos data shows periodic fluctuations with an amplitude of 0.023 magnitudes, and a period of 7.6805 days.[19] As of 2004 however, it is not confirmed to be variable.[20]

  1. ^ Cite error: The named reference CDS was invoked but never defined (see the help page).
  2. ^ a b c d e f g h Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Eggen1992 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Houk1978 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Corben1971 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Corbally1984 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Kervella2021 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Frankowski2006 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Eggen1970 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Koen2002 was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference Samus2004 was invoked but never defined (see the help page).