Caltech Scientist finds planet orbitting 3 suns

In the northern constellation Cygnus (The Swan) a planet the size of Jupiter orbits around three stars 149 light-years (1200 trillion kilometres) from Earth.

From the Caltech news release comes a challenge to the theories about planetary formations in complex solar systems.

Maciej Konacki reported this discovery in the May 2005 issue of Nature.

"If the parent star is orbited by a close stellar companion, then its gravitational pull can significantly truncate a protoplanetary disk around the main star. In the case of HD 188753, the two stellar companions would truncate the disk around the main star to a radius of only 1.3 astronomical units, leaving no space for a planet to form." - http://pr.caltech.edu/media/Press_Releases/PR12716.html

In the case of this triple star system, a red giant and an orange star orbit around a yellow star, according to SpaceFlight News http://www.spaceflightnews.com/forum/lofiversion/index.php/t1161.html.

"The new planet belongs to a common class of extrasolar planets called "hot Jupiters," which are gas giants that zip closely around their parent stars. In this case, the planet whips every 3.3 days around a star that is circled every 25.7 years by a pirouetting pair of stars locked in a 156-day orbit." - NASA Jet Propulsion Laboratory website http://planetquest.jpl.nasa.gov/


Regarding star system HD 188753, perhaps only large planetary masses can survive the combined tidal and solar forces of three stars in close orbit around each other.

My guess is that the planet, which is slightly larger than Jupiter, was too small to become a star.

Thus, in the formation of star systems, the larger masses become stars.

Any masses smaller than a certain size become planets. Judging from this example, the size limit may be slightly more than the size of Jupiter.



The size (diameter, surface area, volume and mass) of Jupiter is as follows:


Diameter: 10⁸ × 1.43 m
Surface area: 10¹⁷ × 0.641 m²
Volume: 10²⁵ × 1.52 m³
Density: 10³ × 1.3 kg/m³ (1.3 g/cm³)
Mass: 10²⁷ × 1.9 kg
Note: 10E8 = 100,000,000
cm = centimetre
m = metres
kg = kilograms
http://www.vendian.org/envelope/dir1/earth_jupiter_sun.html