Editing Planetary system (section)

===Venus zone===
The '''Venus zone''' is the region around a star where a [[terrestrial planet]] would have [[runaway greenhouse]] conditions like [[Venus]], but not so near the star that the atmosphere completely escapes. As with the habitable zone, the location of the Venus zone depends on several factors, including the type of star and properties of the planets such as mass, rotation rate, and atmospheric clouds. Studies of the Kepler spacecraft data indicate that 32% of [[red dwarf]]s have potentially Venus-like planets based on planet size and distance from star, increasing to 45% for [[K-type main-sequence star|K-type]] and [[G-type main-sequence star|G-type]] stars.<ref group=lower-alpha name=footnoteE>For the purpose of this, terrestrial-sized means 0.5–1.4 Earth radii, the "Venus zone" means the region with approximately 1 to 25 times Earth's stellar flux for M and K-type stars and approximately 1.1 to 25 times Earth's stellar flux for G-type stars.</ref> Several candidates have been identified, but spectroscopic follow-up studies of their atmospheres are required to determine whether they are like Venus.<ref>[http://hzgallery.org/venus.html Habitable Zone Gallery - Venus]</ref><ref>{{Cite journal |last1=Kane |first1=Stephen R. |last2=Kopparapu |first2=Ravi Kumar |last3=Domagal-Goldman |first3=Shawn D. |author-link3=Shawn Domagal-Goldman |year=2014 |title=On the Frequency of Potential Venus Analogs from Kepler Data |journal=The Astrophysical Journal |volume=794 |issue=1 |pages=L5 |arxiv=1409.2886 |bibcode=2014ApJ...794L...5K |doi=10.1088/2041-8205/794/1/L5 |s2cid=119178082}}</ref>