WASP-107b
{{Short description|Super Neptune orbiting WASP-107}}
{{Infobox planet
| name = WASP-107b
| image = File:Warm Gas-Giant Exoplanet WASP-107 b (Artist's Concept) (2024-113).png
| caption = Artist's impression of exoplanet WASP-107b.{{cite web|title=Hubble detects helium in the atmosphere of an exoplanet for the first time|url=https://www.spacetelescope.org/news/heic1809/|author=heic1809|website=www.spacetelescope.org|date=2 May 2018|access-date=4 May 2018}}
| discoverer = D. R. Anderson et al.
| discovered = 2017
| discovery_method = WASP-South
| apsis = astron
| semimajor = {{convert|0.0566|±|0.0017|AU|km|abbr=on}}
| period = 5.7214742 d
| star = WASP-107
| mean_radius = 0.96{{±|0.03}} {{Jupiter radius|link=y}}
}}
WASP-107b is a super-Neptune exoplanet that orbits the star WASP-107. It lies 200 light-years away from Earth in the constellation Virgo.{{Cite web|last1=Reed|first1=Nola|title=An Exoplanet First! Helium Spotted on Bizarre Comet-Like World|url=https://www.space.com/40469-helium-detected-alien-planet-atmosphere.html|website=Space.com|date=2 May 2018}} Its discovery was announced in 2017 by a team led by D. R. Anderson via the WASP-South.{{cite journal |first1=D.R. |last1=Anderson |first2=A. Collier |last2=Cameron |display-authors=etal |title=The discoveries of WASP-91b, WASP-105b and WASP-107b: Two warm Jupiters and a planet in the transition region between ice giants and gas giants |url=https://www.aanda.org/articles/aa/pdf/2017/08/aa30439-17.pdf |journal=Astronomy & Astrophysics |volume=604 |number=A110 |date=August 2017 |pages=A110 |doi=10.1051/0004-6361/201730439|arxiv=1701.03776 |bibcode=2017A&A...604A.110A |s2cid=58910823 }}
Planetary orbit
WASP-107b could not have formed in its current orbit. It likely migrated inward from its birth orbit beyond 1 AU due to interaction with the heavier planet WASP-107c. It is in a retrograde orbit, strongly misaligned with the equatorial plane of the parent star. The misalignment angle is equal to 118°{{±|38|19}}.{{citation|arxiv=2101.09371|title=The TESS–Keck Survey. IV. A Retrograde, Polar Orbit for the Ultra-low-density, Hot Super-Neptune WASP-107b|year=2021|doi=10.3847/1538-3881/abd177 |last1=Rubenzahl |first1=Ryan A. |last2=Dai |first2=Fei |last3=Howard |first3=Andrew W. |last4=Chontos |first4=Ashley |last5=Giacalone |first5=Steven |last6=Lubin |first6=Jack |last7=Rosenthal |first7=Lee J. |last8=Isaacson |first8=Howard |last9=Batalha |first9=Natalie M. |last10=Crossfield |first10=Ian J. M. |last11=Dressing |first11=Courtney |last12=Fulton |first12=Benjamin |last13=Huber |first13=Daniel |last14=Kane |first14=Stephen R. |last15=Petigura |first15=Erik A. |last16=Robertson |first16=Paul |last17=Roy |first17=Arpita |last18=Weiss |first18=Lauren M. |last19=Beard |first19=Corey |last20=Hill |first20=Michelle L. |last21=Mayo |first21=Andrew |last22=Mocnik |first22=Teo |last23=Murphy |first23=Joseph M. Akana |last24=Scarsdale |first24=Nicholas |journal=The Astronomical Journal |volume=161 |issue=3 |page=119 |bibcode=2021AJ....161..119R |s2cid=231698426 |doi-access=free }} WASP-107c follows a highly eccentric and inclined orbit with a period of 1088{{±|15|16}} days.
Physical characteristics
WASP-107b is a super-Neptune ice giant exoplanet roughly the size of Jupiter but less than one-tenth of Jupiter's mass, making it one of known lowest density-exoplanets. This is unusual provided that the mean temperature of its upper atmosphere is only
{{convert|500|C|F}}, much lower than that of similarly inflated exoplanets.{{Cite web |last=Lea |first=Robert |date=2024-09-25 |title=James Webb Space Telescope finds 'puffball' exoplanet is uniquely lopsided |url=https://www.space.com/exoplanet-inflated-asymmetry-james-webb-space-telescope |access-date=2024-09-28 |website=Space.com |language=en}} Its highly extended and low density atmosphere coupled with transiting a moderately bright orange dwarf star makes it an attractive target for atmospheric characterization via transmission spectroscopy.{{Cite web|title=First results on the atmosphere of WASP-107b|url=https://wasp-planets.net/2017/09/27/first-results-on-the-atmosphere-of-wasp-107b/|publisher=Wide Angle Search for Planets|date=September 27, 2017}} It is about eight times nearer to its star than Mercury is to the Sun and orbits its star every 5.7 days.
Helium was discovered in the planet's atmosphere in 2018, making it the first time helium was discovered on an exoplanet.{{cite journal|last1=Witze|first1=Alexandra|title=Astronomers spot helium on exoplanet for first time|url=https://www.nature.com/articles/d41586-018-05052-w|journal=Nature|date=2 May 2018|doi=10.1038/d41586-018-05052-w|url-access=subscription}} A follow-up observation with Keck in 2020 showed that the helium absorption extends beyond transit-egress.{{cite journal|last1=Kirk|first1=James|last2=Alam|first2=Munazza K.|last3=Lopez-Morales|first3=Mercedes|last4=Zeng|first4=Li|date=2020-01-21|title=Confirmation of WASP-107b's extended Helium atmosphere with Keck II/NIRSPEC|journal=The Astronomical Journal|volume=159|issue=3|pages=115|doi=10.3847/1538-3881/ab6e66|arxiv=2001.07667|bibcode=2020AJ....159..115K |s2cid=210838904 |doi-access=free }} Extreme ultraviolet radiation from the host star is gradually whittling down the planet's atmosphere, forming a comet-like tail 7 times as long as the radius of the planet.{{Cite web|url=https://wasp-planets.net/2020/01/22/helium-reveals-the-extended-atmosphere-of-wasp-107b/|title=Helium reveals the extended atmosphere of WASP-107b|last=waspplanets|date=2020-01-22|website=WASP Planets|language=en|access-date=2020-01-22}}{{citation|arxiv=2107.08999|year=2021|title=The Posttransit Tail of WASP-107b Observed at 10830 Å|doi=10.3847/1538-3881/ac178a |last1=Spake |first1=J. J. |last2=Oklopčić |first2=A. |last3=Hillenbrand |first3=L. A. |journal=The Astronomical Journal |volume=162 |issue=6 |page=284 |bibcode=2021AJ....162..284S |s2cid=236087427 |doi-access=free}}
In November 2023, scientists discovered that its atmosphere contains water (H2O) vapour and sulfur dioxide (SO2). The clouds on this planet are made up of silicates.{{cite web |url=https://www.npr.org/2023/11/15/1213159944/clouds-made-of-sand-make-for-a-strange-kind-of-rain-on-this-hot-planet|title=Clouds made of sand make for a strange kind of rain on this hot planet |website=NPR News |access-date=16 November 2023}}{{Cite journal |last1=Dyrek |first1=Achrène |last2=Min |first2=Michiel |last3=Decin |first3=Leen |last4=Bouwman |first4=Jeroen |last5=Crouzet |first5=Nicolas |last6=Mollière |first6=Paul |last7=Lagage |first7=Pierre-Olivier |last8=Konings |first8=Thomas |last9=Tremblin |first9=Pascal |last10=Güdel |first10=Manuel |last11=Pye |first11=John |last12=Waters |first12=Rens |last13=Henning |first13=Thomas |last14=Vandenbussche |first14=Bart |last15=Ardevol Martinez |first15=Francisco |date=2023-11-15 |title=SO2, silicate clouds, but no CH4 detected in a warm Neptune |url=https://www.nature.com/articles/s41586-023-06849-0 |journal=Nature |volume=625 |issue=7993 |pages=51–54 |language=en |doi=10.1038/s41586-023-06849-0 |pmid=37967578 |arxiv=2311.12515 |s2cid=265219725 |issn=0028-0836}} The data, along with the unexpectedly low abundance of methane (CH4), suggests a hotter interior and a more massive core than previously estimated. Tidal heating, caused by the planet's slightly elliptical orbit, is believed to be the source of the extra internal heat.{{Cite web |title=Webb Cracks Case of Inflated Exoplanet - NASA Science |url=https://science.nasa.gov/missions/webb/webb-cracks-case-of-inflated-exoplanet/ |access-date=2024-05-21 |website=science.nasa.gov |language=en-US}}
In September 2024 it was revealed that there is an east-west asymmetry in the atmospheric properties (e.g, climate, cloud structure) of WASP-107b, which previously had not been expected for planet of its kind.
See also
References
{{reflist}}
External links
{{2017 in space}}
{{Stars of Virgo}}
{{Portal bar|Astronomy|Stars}}
Category:Exoplanets discovered in 2017
Category:Virgo (constellation)
Category:Exoplanets discovered by WASP