HD 190655

HD 190655
Location of HD 190655 (circled)
Observation data
Epoch J2000.0[1]      Equinox J2000.0[1]
Constellation Cygnus
Right ascension 20h 04m 11.34545s
Declination +45° 05′ 15.3640″
Apparent magnitude (V) 10.114 (combined)[2]
Characteristics
Evolutionary stage Red-giant branch star
Spectral type K2III + (G4IV + M8-L3)[3]
B−V color index 1.153[2]
J−H color index 0.521[4]
J−K color index 0.684[4]
Variable type Eclipsing binary
Astrometry
Radial velocity (Rv)−24.1724±0.002728[5] km/s
Proper motion (μ) RA: -8.419[1] mas/yr
Dec.: −3.176[1] mas/yr
Parallax (π)2.1394 ± 0.3070 mas[1]
Distanceapprox. 1,500 ly
(approx. 470 pc)
Orbit[3]
PrimaryHD 190655 A
CompanionHD 190655 B
Semi-major axis (a)0.4"
(270 AU)
Orbit[3]
PrimaryHD 190655 B
CompanionHD 190655 C
Period (P)5.566513±0.000043 d
Semi-major axis (a)0.0720±0.0013 AU
Inclination (i)82.50+0.58
−0.53°
Details[3]
HD 190655 A
Mass1.69+0.14
−0.10 M☉
Radius11.13+0.32
−0.26 R☉
Luminosity43.3±9.5[6] L☉
Surface gravity (log g)2.577+0.011
−0.009 cgs
Temperature4720±120 K
Metallicity [Fe/H]0.143±0.065 dex
Age2.05+0.56
−0.28 Gyr
HD 190655 B
Mass1.608+0.087
−0.088 M☉
Radius3.61+0.11
−0.12 R☉
Luminosity11.5±1.0 L☉
Temperature5600±100 K
HD 190655 C
Mass66.1+4.1
−3.2 MJup
Radius1.524+0.070
−0.072 RJup
Other designations
BD+44° 3330, Gaia DR3 2082133182277361152, HD 190655, WDS J20042+4505AB, KOI-3886, KIC 8848288, TIC 185060864, TYC 3559-2080-1, GSC 03559-02080, 2MASS J20041135+4505154, WISE J200411.34+450515.3[4]
Database references
SIMBADdata

HD 190655 (KOI-3886) is a hierarchical triple star system located about 1,500 light-years (460 parsecs) away in the northern constellation of Cygnus. It has a combined apparent magnitude of 10.114, making it readily visible using a small telescope with an aperture of 35 mm or larger,[7] but too faint to observe via the naked eye or binoculars.[8]

The system consists of a K-type red giant (HD 190655 A) and a G-type subgiant in a wide binary, with a transiting brown dwarf orbiting the latter. The brown dwarf component is notable in that it is one of the most irradiated objects of its kind, and also the first to be discovered transiting an evolved star. Since it showed planet-like characteristics in a variety of past observations, the brown dwarf has been dubbed the "ultimate planet impostor."[3]

  1. ^ a b c d Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference UCAC4 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Lillo-Box2021 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference simbad was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference apogee was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Campante2023 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference North2014 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference bino was invoked but never defined (see the help page).