What is HD 209458 b?
[[File:Exoplanet_Comparison_HD_209458_b.png|thumb|HD 209458 b compared with Jupiter|337x337px]] '''HD 209458 b''' is an [[exoplanet]]. It orbits [[HD 209458]] in the [[constellation]] [[Pegasus]]. It is [[Approximation|approximately]] 159 [[light year]]s from the [[Solar System]]. A year on HD 209458 b is 3.5 Earth days. It has an [[Estimation|estimated]] [[surface]] [[temperature]] of about 1,000&nbsp;°C (about 1,800&nbsp;°F). Its mass is 220 times that of [[Earth]].<ref>{{Cite web|title=Extrasolar planet HD 209458 b (Osiris)|url=http://exoplanets.co/exoplanets-tutorial/extrasolar-planet-hd-209458-b.html|access-date=2020-09-23|website=exoplanets.co|archive-date=2020-08-01|archive-url=https://web.archive.org/web/20200801144011/http://exoplanets.co/exoplanets-tutorial/extrasolar-planet-hd-209458-b.html|url-status=dead}}</ref> It is the first exoplanet to be discovered with the transit method. Also this the first exoplanet to be discovered to have an atmosphere. The atmosphere contains [[water vapor]], [[carbon monoxide]], [[hydrogen cyanide]], [[methane]], [[ammonia]] and [[acetylene]]. The exoplanet does have a magnetic field, but the magnetic field was about one tenth as strong as Jupiter's ==References== {{reflist}} {{science-stub}} [[Category:Exoplanets]]