HD 195019

HD 195019
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Delphinus
Right ascension 20h 28m 18.6367s[1]
Declination +18° 46′ 10.180″[1]
Apparent magnitude (V) 6.97 + 10.60[2]
Characteristics
Spectral type G1V[3] + K3:[4]
B−V color index 0.662±0.007[5]
Astrometry
Radial velocity (Rv)−91.290±0.0039[6] km/s
Proper motion (μ) RA: 349.620(16) mas/yr[1]
Dec.: −56.618(19) mas/yr[1]
Parallax (π)26.6465 ± 0.0225 mas[1]
Distance122.4 ± 0.1 ly
(37.53 ± 0.03 pc)
Absolute magnitude (MV)4.01[5]
Details[7]
HD 195019 A
Mass1.08±0.01[8] M☉
Radius1.47±0.04[8] R☉
Luminosity2.23±0.02[8] L☉
Surface gravity (log g)4.13±0.02[8] cgs
Temperature5,825±56[8] K
Metallicity [Fe/H]0.068±0.030[9] dex
Rotational velocity (v sin i)2.47±0.50[9] km/s
Age7.7±0.7[8] Gyr
HD 195019 B
Mass0.7[10] M☉
Surface gravity (log g)4.46[11] cgs
Temperature4,652[11] K
Rotational velocity (v sin i)1.71[11] km/s
Other designations
BD+18° 4505, Gaia DR2 1815418118373631360, HD 195019, HIP 100970, SAO 106138, WDS J20283+1846A, LTT 15981, NLTT 49312, GCRV 12790, 2MASS J20281860+1846103[12]
Database references
SIMBADdata

HD 195019 is a binary star system in the northern constellation of Delphinus. The brighter star has a close orbiting exoplanet companion. This system is located at a distance of 122 light years from the Sun based on parallax measurements,[1] but it is drifting closer with a radial velocity of −91.3 km/s.[6] Although it has an absolute magnitude of 4.01,[5] at that distance the system is considered too faint to be viewed with the naked eye, having a combined apparent visual magnitude of 6.87.[5] However, it should be readily visible with a pair of binoculars or a small telescope.[13]

The spectrum of the primary member, designated component A, presents as a G-type main-sequence star with a stellar classification of G1V.[3] An older stellar classification of G3 V/IV[14] suggested it may be near the end of its main sequence lifespan and is evolving into a subgiant star.[13] This is an older star with an estimated age of nearly 8[8] billion years and a low level of magnetic activity in its chromosphere.[8] The abundance of iron is near solar.[9] The star has a mass similar to the Sun but a larger radius. It is radiating 2.23 times the luminosity of the Sun from its photosphere at an effective temperature of 5,825 K.[8]

The co-moving companion, component B, was first reported by G. W. Hough in 1881. As of 2016, it is located at an angular separation of 3.40″ along a position angle of 334° relative to the primary.[2] This corresponds to a projected separation of 131 AU. This is a K-type star with 70% of the mass of the Sun[10] and is magnitude 10.60.[2]

  1. ^ a b c d e Cite error: The named reference Gaia DR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Mason_et_al_2001 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Gray_et_al_2001 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Bidelman_1985 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Soubiran_et_al_2018 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Takeda2005 was invoked but never defined (see the help page).
  8. ^ a b c d e f g h i Cite error: The named reference Bonfanti_et_al_2016 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Butler2006 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Quarles_et_al_2020 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Rice_Brewer_2020 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Kaler was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Fischer1999 was invoked but never defined (see the help page).