HD 28185 b

Planetbox begin
name = HD 28185 b

Planetbox star
star = HD 28185
constell = Eridanus
RA = RA|04|26|26.3205
DEC = DEC|−10|33|02.955
dist_ly = 148
dist_pc = 46
class = G5VPlanetbox orbit
semimajor = 1.031 ± 0.060
eccentricity = 0.070 ± 0.040
period = 383.0 ± 2.0
ang_dist = 26
long_peri = 351 ± 25
t_peri = 2,451,863 ± 26
semi-amp = 161 ± 11Planetbox character
mass = >5.72 ± 0.93Planetbox discovery
discovery_date = 4 April 2001
discoverers = Santos "et al."
discovery_method = Radial velocity
discovery_site = flag|Switzerland
discovery_status = Published

HD 28185 b is an extrasolar planet approximately 148 light-years away in the constellation Eridanus. The planet was discovered orbiting the Sun-like star HD 28185 in April of 2001 as a part of the CORALIE survey for southern extrasolar planets. HD 28185 b orbits its sun in circular orbit that is at the inner edge of its star's habitable zone.cite journal|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2006ApJ...649.1010J&db_key=AST&nosetcookie=1|author=Jones, Barrie W.; Sleep, P. Nick; Underwood, David R.|title=Habitability of Known Exoplanetary Systems Based on Measured Stellar Properties|journal=The Astrophysical Journal|volume=649|issue=2|year=2006|pages=1010 – 1019|doi=10.1086/506557]

Discovery

Like the majority of known extrasolar planets, HD 28185 b was discovered by detecting small periodic variations in the radial velocity of its parent star caused by the gravitational attraction of the planet. This was achieved by measuring the Doppler shift of the star's spectrum. In 2001 it was announced that HD 28185 exhibited a wobble along the line of sight with a period of 383 days, with an amplitude indicating a mass 5.72 times that of Jupiter. [cite journal|url=http://www.edpsciences.org/articles/aa/abs/2001/45/aah3054/aah3054.html|author=Santos, N. et al.|title=The CORALIE survey for southern extra-solar planets VI. New long-period giant planets around HD 28185 and HD 213240|journal=Astronomy and Astrophysics|volume=379|year=2001|pages=999 – 1004|doi=10.1051/0004-6361:20011366]

Orbit and mass

HD 28185 b takes 1.04 years to orbit its parent star. Unlike most known long-period planets, the orbit of HD 28185 b has a low eccentricity, comparable to that of Mars in our solar system. [cite journal|url=http://www.journals.uchicago.edu/doi/abs/10.1086/504701|author=Butler, R. et al.|title=Catalog of Nearby Exoplanets|journal=The Astrophysical Journal|volume=646|pages=505 – 522|year=2006|doi=10.1086/504701 ( [http://exoplanets.org/planets.shtml web version] )] The orbit lies entirely within its star's habitable zone.

The amplitude of the radial velocity oscillations means that the planet has a mass at least 5.7 times that of Jupiter in our solar system. However, the radial velocity method only yields a minimum value on the planet's mass, depending on the orbital inclination to our line of sight. Therefore, the true mass of the planet may be much greater than this lower limit.

Characteristics

Given the planet's high mass, it is most likely to be a gas giant with no solid surface. Since the planet has only been detected indirectly through observations of the star, properties such as its radius, composition and temperature are unknown.

Since HD 28185 b orbits in its star's habitable zone, some have speculated on the possibility of life on worlds in the HD 28185 system. [cite web|url=http://nai.nasa.gov/news_stories/news_detail.cfm?ID=126|title=Extrasolar Planets with Earth-like Orbits|author=Mullen, L.|accessyear=2006|accessmonthday=22 July|year=2001] While it is unknown whether gas giants can support life, simulations of tidal interactions suggest that HD 28185 b could harbour Earth-mass satellites in orbit around it for many billions of years. [cite journal|url=http://adsabs.harvard.edu/abs/2002ApJ...575.1087B|author=Barnes, J., O'Brien, D.|title=Stability of Satellites around Close-in Extrasolar Giant Planets|journal=Astrophysical Journal|volume=575|issue=2|pages=1087 – 1093|year=2002|doi=10.1086/341477] Such moons, if they exist, may be able to provide a habitable environment, though it is unclear whether such satellites would form in the first place. [cite journal|url=http://www.nature.com/nature/journal/v441/n7095/abs/nature04860.html|author=Canup, R., Ward, W.|title=A common mass scaling for satellite systems of gaseous planets|journal=Nature|volume=441|year=2006|pages=834 – 839|doi=10.1038/nature04860] Additionally, a small planet in one of the gas giant's Trojan points could survive in a habitable orbit for long periods. [cite journal|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2007A%26A...474.1023S&db_key=AST&nosetcookie=1|title=Survey of the stability region of hypothetical habitable Trojan planets|author=Schwarz, R.; Dvorak, R.; Süli, Á.; Érdi, B.|journal=Astronomy and Astrophysics|volume=474|issue=3|pages=1023 – 1029|doi=10.1051/0004-6361:20077994|accessdate=2008-08-19]

See also

* 51 Pegasi b
* Iota Horologii b
* Gliese 876b

References

External links

* [http://simbad.u-strasbg.fr/sim-id.pl?Ident=HD+28185b HD 28185 b] on " [http://simbad.u-strasbg.fr/simbad/ SIMBAD] "
* [http://exoplanet.eu/planet.php?p1=HD+28185&p2=b HD 28185 b] on " [http://exoplanet.eu/index.php Extrasolar Planets Encyclopaedia] "
* [http://www.extrasolar.net/planettour.asp?StarCatId=normal&PlanetId=158 HD 28185 b] on " [http://www.extrasolar.net/ Extrasolar Visions] "