HD 188753

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HD 188753 ABC

HD 188753 in the Cygnus constellation
Observation data
Epoch J2000.0
Constellation
(pronunciation)		 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 yr
Semimajor axis (a) 12.3 AU"
Eccentricity (e) 0.5
Inclination (i) ?°
Longitude of the 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 K0 (orange dwarf), and its companion (HD 188753 C) is an M2-type (red dwarf). These orbit each other in 156 days, and the primary in 25.7 years.[4]

[edit] Planetary system

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

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.[6][4]

Since HD 188753 was orbiting a multi-star system, Konacki refers to planets of this type as "Tatooine planets" after Luke Skywalker's home world.[7] The detection of this planet has been challenged by Eggenberger et al.[8][9]

The planet, a Hot Jupiter gas giant slightly more massive than Jupiter, orbits the star HD 188753 A. The planet, which is at least 14% more massive 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. Due to its close distance to the star, the planet is likely to be about 1.2 times larger than Jupiter in radius.

The HD 188753 system
Planet
(in order from star)		 Mass
(MJ)		 Orbital period
(days)		 Semimajor axis
(AU)		 Eccentricity
Ab >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

HD188753 orbit
HD188753 orbit

[edit] References

  1. ^ http://cdsweb.u-strasbg.fr/ftp/cats/v/122/alias.dat
  2. ^ [1][dead link]
  3. ^ http://joy.chara.gsu.edu/~nils/2000AJ....119.3084H.pdf
  4. ^ a b c JPL: NASA Scientist Finds World With Triple Sunsets
  5. ^ On the circularity of orbit of certain spectroscopic binaries
  6. ^ Access : The triple sunset that should not exist : Nature News
  7. ^ [2]
  8. ^ Maciej Konacki, Home Page
  9. ^ [astro-ph/0702574] No evidence of a hot Jupiter around HD 188753 A
  • 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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