HD 40307

Starbox begin
name = HD 40307Starbox observe
epoch = J2000.0 (ICRS)
constell = Pictor
ra = RA|05|54|04.2409SIMBAD link|HD+40307|HD 40307, entry, SIMBAD. Accessed on line June 18, 2008.]
dec = DEC|−60|01|24.498
appmag_v = 7.135Starbox character
class = K2.5V
u-b =
b-v = 0.93
v-r =
r-i = Starbox astrometry
radial_v = +30.4
prop_mo_ra = −51.76
prop_mo_dec = −60.44
parallax = 77.95
p_error = 0.53
parallax_footnote =
absmag_v = 6.59Starbox detail
mass = 0.75^+0.03_−0.04 [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/117/table1&recno=3947 HD 40307] , entry, CDS database [http://vizier.u-strasbg.fr/viz-bin/Cat?J/A+A/418/989 J/A+A/418/989] ; described in The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ~14 000 F and G dwarfs, B. Nordström, M. Mayor, J. Andersen, J. Holmberg, F. Pont, B. R. Jørgensen, E. H. Olsen, S. Udry, and N. Mowlavi, "Astronomy and Astrophysics" 418 (May 2004), pp. 989–1019. bibcode|2004A&A...418..989N. doi|10.1051/0004-6361:20035959.]
radius = 0.716 ± 0.010 [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=J/A%2bA/450/735/table2&recno=2686 HD 40307] , entry, CDS database [http://cdsarc.u-strasbg.fr/viz-bin/Cat?J/A%2bA/450/735 J/A+A/450/735] ; described in Effective temperature scale and bolometric corrections from 2MASS photometry, E. Masana, C. Jordi, and I. Ribas, "Astronomy and Astrophysics" 450, #2 (May 2006), pp. 735–746. bibcode|2006A&A...450..735M. doi|10.1051/0004-6361:20054021.]
gravity = 4.47 ± 0.16
luminosity_bolometric = 0.23
luminosity_visual = 0.20
temperature = 4977 ± 59
metal = [Fe/H] = −0.31 ± 0.03
rotation = ~48 days
age = Starbox catalog
names = HIP 27887, GJ 2046, SAO 249388, TYC 8892-1247-1Starbox reference
Simbad = HD+40307
ARICNS =

HD 40307 is a K-type main sequence star approximately 42 light-years away in the constellation of Pictor (the Easel). As of 2008, three extrasolar planets have been discovered to be orbiting the star. [http://www.msnbc.msn.com/id/25191635/ Three super-Earths found around one star] , Jeanna Bryner, MSNBC, June 16, 2008. Accessed on line June 18, 2008.] The name of this star comes from its identifier in the Henry Draper catalogue.

Star

HD 40307 is a main sequence star of the spectral type K2.5V. The star has around 75 percent of the Sun's mass, a smaller radius than the Sun, approximately 20 percent of the Sun's visual luminosity,From M_V=6.59 for HD 40307 and M_V=4.83 for the Sun.] and 23 percent of its bolometric luminosity. The ratio of iron to hydrogen in HD 40307 is thought to be around 50 percent of that in the Sun.

Planetary system

In June 2008, the European Southern Observatory (ESO) announced the discovery of three Super-Earths orbiting the star. All three planets were detected by the radial velocity method, using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph system. [cite news|url=http://news.bbc.co.uk/1/hi/sci/tech/7457307.stm|title=Trio of 'super-Earths' discovered |coauthors=Mayor et al.|date=2008-06-16|work=BBC news|accessdate=2008-06-16]

The discovery was based on five years of radial velocity observations. [cite web |url=http://www.eso.org/public/outreach/press-rel/pr-2008/pr-19-08.html |title=ESO 19/08 - A Trio of Super-Earths |accessdate=2008-06-21 |publisher=European Southern Observatory |date=2008-06-16] All three planets are believed to have highly circular orbits at an orbital distance from their parent star that would be well within the orbit of Mercury in the Solar system. The planets are more massive than the Earth, but are expected to be less massive than both Uranus and Neptune. In addition to the three planets close to the central star, a small drift of the radial-velocity residuals reveals the presence of another companion in the system, the nature of which is still unknown.cite journal|author= M. Mayor, S. Udry, C. Lovis, F. Pepe, D. Queloz, W. Benz, J.-L. Bertaux, F. Bouchy, C. Mordasini, D. Segransan|title=The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)|journal= "Submitted to" Astronomy & Astrophysics|bibcode=2008arXiv0806.4587M|url=http://www.arxiv.org/abs/0806.4587|accessdate=2008-06-30] It is expected that finding an extrasolar planet the size of the Earth will be possible in the future, although it is difficult with present technology. PlanetboxOrbit
exoplanet = b
mass = >0.0132 [http://exoplanet.eu/star.php?st=HD+40307 Star : HD 40307] , "Extrasolar Planets Encyclopaedia". Accessed on line June 18, 2008.]
period = 4.3115 ± 0.0006
semimajor = 0.047
eccentricity = 0.0PlanetboxOrbit
exoplanet = c
mass = >0.0216
period = 9.620 ± 0.002
semimajor = 0.081
eccentricity = 0.0PlanetboxOrbit
exoplanet = d
mass = >0.0288
period = 20.46 ± 0.01
semimajor = 0.134
eccentricity = 0.0

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