KELT-20b

{{Short description|Exoplanet orbiting KELT-20}}

{{Infobox planet

| image = Ultra-Hot Jupiter-Sized Exoplanet Illustration (2022-014).png

| caption = An artist's impression of ultra-hot Jupiter planet KELT-20b orbiting its host star.

| name = KELT-20b

| discoverer =

| discovery_site = KELT

| discovered = 2017

| discovery_method = Transit method

{{odlist|MASCARA-2b}}

| apsis = astron

| semimajor = 0.0542 AU

| period = 3.6127647 d = 3.474

| inclination = 86.12

| star = KELT-20

| mean_radius = 1.741 {{Jupiter radius|link=y}}

| mass = <3.382 {{Jupiter mass|link=y}}

| density = <0.806 g cm⁻³

| single_temperature =

}}

KELT-20b, also known as MASCARA-2b, is an exoplanet announced in 2017. It is an Ultra-hot Jupiter orbiting an A-type star. The carbon monoxide, steam{{citation|arxiv=2201.02261|year=2022|title=Strong H₂O and CO Emission Features in the Spectrum of KELT-20b Driven by Stellar UV Irradiation|doi=10.3847/2041-8213/ac4968 |doi-access=free |last1=Fu |first1=Guangwei |last2=Sing |first2=David K. |last3=Lothringer |first3=Joshua D. |last4=Deming |first4=Drake |last5=Ih |first5=Jegug |last6=Kempton |first6=Eliza M. -R. |last7=Malik |first7=Matej |last8=Komacek |first8=Thaddeus D. |last9=Mansfield |first9=Megan |last10=Bean |first10=Jacob L. |journal=The Astrophysical Journal Letters |volume=925 |issue=1 |pages=L3 |bibcode=2022ApJ...925L...3F }}{{citation|arxiv=2208.04759|year=2023|title=Unifying High- and Low-resolution Observations to Constrain the Dayside Atmosphere of KELT-20b/MASCARA-2b|doi=10.3847/1538-3881/ac9f40 |doi-access=free |last1=Kasper |first1=David |last2=Bean |first2=Jacob L. |last3=Line |first3=Michael R. |last4=Seifahrt |first4=Andreas |last5=Brady |first5=Madison T. |last6=Lothringer |first6=Joshua |last7=Pino |first7=Lorenzo |last8=Fu |first8=Guangwei |last9=Pelletier |first9=Stefan |last10=Stürmer |first10=Julian |last11=Benneke |first11=Björn |last12=Brogi |first12=Matteo |last13=Désert |first13=Jean-Michel |journal=The Astronomical Journal |volume=165 |issue=1 |page=7 |bibcode=2023AJ....165....7K }} and neutral iron{{citation|arxiv=2201.08759|year=2022|title=Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b|doi=10.1051/0004-6361/202142395 |last1=Yan |first1=F. |last2=Reiners |first2=A. |last3=Pallé |first3=E. |last4=Shulyak |first4=D. |last5=Stangret |first5=M. |last6=Molaverdikhani |first6=K. |last7=Nortmann |first7=L. |last8=Mollière |first8=P. |last9=Henning |first9=Th. |last10=Casasayas-Barris |first10=N. |last11=Cont |first11=D. |last12=Chen |first12=G. |last13=Czesla |first13=S. |last14=Sánchez-López |first14=A. |last15=López-Puertas |first15=M. |last16=Ribas |first16=I. |last17=Quirrenbach |first17=A. |last18=Caballero |first18=J. A. |last19=Amado |first19=P. J. |last20=Galadí-Enríquez |first20=D. |last21=Khalafinejad |first21=S. |last22=Lara |first22=L. M. |last23=Montes |first23=D. |last24=Morello |first24=G. |last25=Nagel |first25=E. |last26=Sedaghati |first26=E. |last27=Zapatero Osorio |first27=M. R. |last28=Zechmeister |first28=M. |journal=Astronomy & Astrophysics |volume=659 |pages=A7 |bibcode=2022A&A...659A...7Y |s2cid=246210387 }} detection in the atmosphere of KELT-20b was announced in 2022.