File:Exoplanet_Comparison_HD_209458_b.png · Wikimedia Commons · See Wikimedia Commons
Astronomical data · SIMBAD
- Object type
- Pl
- Distance
- 157 light-years
- Coordinates
- RA 330.7949° · Dec 18.8843°
via SIMBAD · CDS Strasbourg
Key facts
- Discovered by
- D. Charbonneau , T. Brown , David Latham, M. Mayor , G.W. Henry , G. Marcy , R.P. Butler , S.S. Vogt
- Discovery site
- High Altitude Observatory , Geneva Observatory
- Discovery date
- September 9, 1999
- Detection method
- Radial velocity
- Semi major axis
- 0.04707 AU (7,042,000 km)
- Eccentricity
- <0.0081
- Orbital period sidereal
- 3.524 748 59 (38) d , 84.59396616 h
- Inclination
- 86.710° ± 0.050°
- Time of periastron
- 2 452 826 .629 283 (87) JD
- Semi amplitude
- 84.27 +0.69, −0.70 m/s
- Star
- HD 209458
- Mean radius
- 1.359 +0.016, −0.019 R J
- Mass
- 0.682 +0.014, −0.015 M J
- Mean density
- 0.333 +0.014, −0.013 g/cm
- Surface gravity
- 9.2 m/s (0.94 g )
- Albedo
- 0.096 ± 0.016 ( geometric )
- Temperature
- 1499 ± 15 K (1,226 °C; 2,239 °F, dayside) , 972 ± 44 K (699 °C; 1,290 °F, nightside)
via Wikipedia infobox
~17 min read
Encyclopedic overview
HD 209458 b is an exoplanet, specifically a hot Jupiter, that orbits the solar analog HD 209458 in the constellation Pegasus, some 157 light-years (48 parsecs) from the Solar System. It is sometimes informally called Osiris. The radius of the planet's orbit is 0.047 AU (7.0 million km; 4.4 million mi), or one-eighth the radius of Mercury's orbit (0.39 AU (36 million mi; 58 million km)). This small orbital distance results in a year that is 3.5 Earth-days long and an estimated surface temperature of about 1,000 °C (1,800 °F; 1,300 K). Its mass is 220 times that of Earth (0.69 Jupiter masses) and its volume is some 2.5 times greater than that of Jupiter. The high mass and volume of HD 209458 b indicate that it is a gas giant.
HD 209458 b represents a number of milestones in exoplanetary research. It was the first of many categories:
Excerpted from Wikipedia’s “HD 209458 b” article, available under the CC BY-SA 4.0 licence.