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HD 69830 is an orange dwarf star approximately 41 light-years away in the constellation of Puppis (the Poop Deck). In 2005, the Spitzer Space Telescope discovered an asteroid belt orbiting the star.[2] The belt appears to be much bigger and more active than the Solar system's belt. As of 2006, it has been confirmed that three, Neptune-mass extrasolar planets orbit the star and acting like shepherds of the asteroid belt.[3]
[edit] Distance and visibilityHD 69830 is an orange dwarf star of the spectral type K0V. The star has a mass of about 86 percent the Sun, 89 percent of its radius, and 45 percent of its luminosity. Containing less then 89 to 93 percent less iron than the Sun, recent age estimate indicated that the star is about 7 billion years. HD 69830 is located about 41.0 light-years from the Sun, lying in the northeastern part of the constellation of Puppis (the Poop Deck). The star can be found east of Sirius, southwest of Procyon, northeast of Delta Canis Majoris, and north of Zeta Puppis. [edit] Planetary system
[edit] Asteroid belt
In 2005, the Spitzer Space Telescope detected dust in the HD 69830 system consistent with the existence of an asteroid belt twenty times more massive than that in our own system. The belt was originally thought to be located inside an orbit equivalent to that of Venus in our own solar system, which would place it between the orbits of the second and third planets. The belt would be so massive that the nights on any nearby planets would be lit up by zodiacal light 1000 times brighter than that seen on Earth, easily outshining the Milky Way. Further analysis of the spectrum of the belt revealed that it is composed of highly processed material, and resembles a disrupted P-type or D-type asteroid of ~30 km radius, containing many small icy grains which would not survive at close distances to the star. Instead, it seems more likely that the belt is located outside the orbit of the outermost planet, around 1 AU from the star. This region contains the 2:1 and 5:2 mean motion resonances with HD 69830 d.[4] [edit] Planets
On May 17 2006, a team of astronomers using the European Southern Observatory's (ESO) HARPS spectrograph on the 3.6-metre La Silla telescope in the Atacama desert, Chile, announced the discovery of three extrasolar planets orbiting the star. With minimum masses between 10 to 18 times that of the Earth, all three planets are presumed to be similar to the planets Neptune or Uranus. The previously discovered asteroid belt appears to lie between the orbits of the planet HD 69830 c and HD 69830 d. As of 2005, no planet with more than half the mass of Jupiter has been detected within three astronomical units of HD 69830. The outermost planet discovered appears to be within the system's habitable zone, where liquid water would remain stable (more accurate data on the primary star's luminosity will be required to know for sure where the habitable zone is). HD 69830 is the first extrasolar planetary system around a Sun-like star without any known planets comparable to Jupiter or Saturn in mass. Though, a Jupiter sized world is still possible farther out from its star. [edit] References In Popular Culture
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