HD 188753

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HD 188753 ABC

HD 188753 in the Cygnus constellation
Observation data
Equinox J2000.0
Constellation Cygnus
Right ascension 19h 54m 58.37s
Declination +41° 52′ 17.5″
Apparent magnitude (V) +7.43
Characteristics
Spectral type GV / K0V / MV
U-B color index  ?
B-V color index  ?
Variable type  ?
Astrometry
Radial velocity (Rv) -23.5 km/s
Proper motion (μ) RA: -52.76 mas/yr
Dec.: 284.44 mas/yr
Parallax (π) 22.31 ± 0.78 mas
Distance 149 ly (46 pc)
Absolute magnitude (MV) 4.17
Visual binary orbit
Companion HD 188753 BC
Period (P) 25.7 a
Semimajor axis (a) 12.3 AU"
Eccentricity (e) 0.5
Inclination (i)  ?°
Node (Ω)  ?°
Periastron epoch (T)  ?
Details
Mass 1.06 / ? / ? M☉
Radius 1.28 / ? / ? R☉
Luminosity 1.6 / ? / ? L☉
Temperature 5750 K
Metallicity  ?
Rotation  ?
Age 5600 million years
Other designations
HO 581

HD 188753 is a triple star system approximately 149 light-years away in the constellation Cygnus. The system is also known as ADS 13125, Ho 581, BD+41°3535 [1] [2], HIP 98001, and WDS 19550+4152 [3]. This star system is only the second triple-star system known to have a planet orbiting it [4], HD 188753 Ab, which was discovered in 2005 by Polish astronomer Dr. Maciej Konacki.

Contents

[edit] Stars

The primary star (HD 188753 A) is a 1.06 solar mass G-type (yellow dwarf).

Orbiting this at a distance separated from the primary star at approximately midway between the Sun-Saturn and Sun-Uranus distance: 12.3 AU, are two stars orbiting each other. These have a total mass of 1.63 solar masses and orbit the primary with an eccentricity of 0.50 (an earlier estimate put the eccentricity at 0.26±0.07 [5]).

The secondary (HD 188753 B) has a spectral class of K (orange dwarf), and the tertiary (HD 188753 C) is an M-type (red dwarf). These orbit each other in 156 days, and the primary in 25.7 years.[6]

[edit] Planetary system

In 2005 the discovery of HD 188753 Ab was the first known planet in a triple star system. It has been discovered by a Polish astronomer working in the United States, Dr. Maciej Konacki [7] [8].

An artist's conception of HD 188753 Ab looking at its suns.
An artist's conception of HD 188753 Ab looking at its suns.

The planet, a gas giant slightly larger than Jupiter, orbits the star HD 188753 A. The planet, which is at least 14% larger than Jupiter, orbits the main star once every 80 hours or so (3.3 days), at a distance of about 8 Gm, a twentieth of the distance between Earth and the Sun.

Companion
(In order from star)		 Mass
(MJ)		 Orbital period
(days)		 Semimajor axis
(AU)		 Eccentricity
b >1.14 ± 0.1 3.3481 ± 0.0009 0.0446 ± 0.001 0.00


[edit] HD 188753 in fiction and mythology

See Rizq for a discussion of the role HD 188753 plays in Nuwaubian mythology.

[edit] See also


[edit] References

  • Griffin, R.F., The multiple star HD 188753 (ADS 13125), The Observatory, Vol. 97, pp. 15-18, 1977
  • Bowman, Lee (Jul. 14, 2005). "Planet with a view: Three suns shine in Cygnus". The Plain Dealer, pg. A2.


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