HD 69830

Starbox begin
name = HD 69830 Starbox observe
epoch = J2000.0
constell = Puppis
ra = RA|08|18|23.9473
dec = DEC|-12|37|55.824
appmag_v = +5.95 Starbox character
class = K0V
r-i = 0.36
v-r = 0.40
b-v = 0.753
u-b = 0.34
variable = none Starbox astrometry
radial_v = +30.4
prop_mo_ra = 279.29
prop_mo_dec = −988.99
parallax = 80.32
parallax_footnote = [cite web|url=http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=I/311/hip2&recno=40567|title=HIP 40693|work=Hipparcos, the New Reduction|author=van Leeuwen, F.|year=2007|accessdate=2008-08-17]
p_error = 0.35
absmag_v = 5.85Starbox detail
age = (7 ± 3) × 10⁹
metal = 89 ± 4 %
mass = 0.86 ± 0.03
radius = 0.89
gravity = 4.47
rotation = 21.5 days
luminosity = 0.60 ± 0.03
temperature = 5385 ± 20 Starbox catalog
names = HR 3259, Gliese 302, HIP 40693, SAO 154093, LHS 245, BD −12°2449 Starbox reference
Simbad = HD+69830

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. [cite journal|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2005ApJ...626.1061B&db_key=AST&nosetcookie=1|author=Beichman, C.A. et al.|title=An Excess Due to Small Grains around the Nearby K0 V Star HD 69830: Asteroid or Cometary Debris?|journal=The Astrophysical Journal|volume=626|issue=2|pages=1061–1069|year=2005|doi=10.1086/430059] 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. [cite journal|url=http://www.nature.com/nature/journal/v441/n7091/abs/nature04828.html|author=Lovis, C. et al.|title=An extrasolar planetary system with three Neptune-mass planets|journal=Nature|volume=441|issue=7091|pages=305–309|year=2006|doi=10.1038/nature04828|format=abstract]

Distance and visibility

HD 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.

Planetary system

PlanetboxOrbit
exoplanet = b
mass = >0.033
period = 8.667 ± 0.003
semimajor = 0.0785
eccentricity = 0.1 ± 0.04PlanetboxOrbit
exoplanet = c
mass = >0.038
period = 31.56 ± 0.04
semimajor = 0.186
eccentricity = 0.13 ± 0.06PlanetboxOrbit
exoplanet = d
mass = >0.058
period = 197 ± 3
semimajor = 0.63
eccentricity = 0.07 ± 0.07PlanetboxOrbit disk
disk = Debris disk
periapsis = 0.93
apoapsis = 1.16

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. [cite journal |url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2007ApJ...658..584L&db_key=AST&nosetcookie=1 |author=Lisse, C.M. et al.|title=On the Nature of the Dust in the Debris Disk Around HD 69830|journal=The Astrophysical Journal|volume=658|issue=1|pages=584–592|year=2007|doi=10.1086/511001]

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.

References In Popular Culture

* In the Bestiarum included with the special editions of Halo 3, it declares HD 69830 as the home star of the Jackals, specifically stating they come from the moon of the third planet, at the inner edge of the asteroid belt.

See also

* HD 169830

References

External links

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* [http://www.lpl.arizona.edu/~rory/research/xsp/dynamics/ Extrasolar Planet Interactions] by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona