HD 190007

HD 190007

Four representative light curves for HD 190007, adapted from Burt et al. (2020)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila[2]
Right ascension 20h 02m 47.04569s[3]
Declination +03° 19′ 34.2658″[3]
Apparent magnitude (V) 7.46[1]
Characteristics
Evolutionary stage main sequence[4]
Spectral type K5 V[5]
U−B color index +1.09[6]
B−V color index +1.11[6]
Variable type BY Dra[7]
Astrometry
Radial velocity (Rv)−30.268±0.0013[8] km/s
Proper motion (μ) RA: −90.383 mas/yr[3]
Dec.: 119.430 mas/yr[3]
Parallax (π)78.6465 ± 0.0198 mas[3]
Distance41.47 ± 0.01 ly
(12.715 ± 0.003 pc)
Absolute magnitude (MV)6.91[2]
Details
Mass0.77±0.02[1] M☉
Radius0.80[9] R☉
Luminosity0.24[9] L☉
Surface gravity (log g)4.50[10] cgs
Temperature4,610±20[1] K
Metallicity [Fe/H]0.16[10] dex
Rotation28.626±0.046 d[1]
Other designations
V1654 Aql, BD+02°4076, GJ 775, HD 190007, HIP 98698, SAO 125379[11]
Database references
SIMBADdata
ARICNSdata

HD 190007, also known as Gliese 775, is a star with a close orbiting exoplanet in the constellation of Aquila. Parallax measurements by Gaia put the star at a distance of 41.5 light-years (12.7 parsecs) away from the Sun. It is drifting closer with a radial velocity of −30.3 km/s,[8] and is predicted to come within 11.8 light-years in 375,000 years.[12] The star has an absolute magnitude of 6.91,[2] but at its present distance the apparent visual magnitude is 7.46,[1] which is too faint to be viewed with the naked eye.

The variability of the brightness of HD 190007 was discovered by George Wesley Lockwood et al. from data taken during a photometry program at Lowell Observatory carried out from 1984 through 1995.[13] It was given its variable star designation, V1654 Aquilae, in 1997.[14]

The spectrum of HD 190007 matches a K-type main-sequence star with a stellar classification of K5 V.[5] It is classified as a BY Draconis variable, showing a moderate level of magnetic activity in its chromosphere[4] with a suspected activity cycle lasting 13.7 years.[15] The star displays a mild enhancement of metals and its age is uncertain. It has 77%[1] of the mass of the Sun, 80% of the Sun's radius,[9] and is spinning with a rotation period of 28.6 days.[1] HD 190007 is radiating 24%[9] of the luminosity of the Sun from its photosphere at an effective temperature of 4,610 K.[1]

  1. ^ a b c d e f g h i Cite error: The named reference Burt2020 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference xhip was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Stalport2023 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference kirkpatrick1991 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference EgUBV was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Soubiran_et_al_2018 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference Chandler was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Mishenina was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Bailer-Jones_et_al_2018 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Lockwood was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Kazarovets was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Obridko_et_al_2022 was invoked but never defined (see the help page).