WASP-12b
{{Short description|Hot Jupiter exoplanet in the constellation Auriga}}
{{Use mdy dates|date=March 2022|cs1-dates=l}}
{{Infobox planet
| name = WASP-12b
| image = Exoplanet Comparison WASP-12 b.png
| caption = Size comparison of WASP-12b (right) with Jupiter
| discoverer = Cameron et al. (SuperWASP)
| discovery_site = SAAO
| discovery_method = Transit
| apsis = astron
| semimajor = {{val|0.0234|0.00056|0.00050|u=AU}}
| eccentricity = 0.049 ± 0.015
| period = {{val|1.0914199|0.0000002|ul=d}}
| inclination = {{val|81.92|1.51|u=°}}
| arg_peri = {{val|-74|13|10|u=°}}
| star = WASP-12
| mean_radius = {{val|1.937|0.056}}{{Cite journal |last1=Chakrabarty |first1=Aritra|last2=Sengupta|first2=Sujan|date=2019-07-01 |title=Precise Photometric Transit Follow-up Observations of Five Close-in Exoplanets: Update on Their Physical Properties |journal=The Astronomical Journal |volume=158 |issue=1 |page=39 |doi=10.3847/1538-3881/ab24dd |doi-access=free |arxiv=1905.11258 |bibcode=2019AJ....158...39C |issn=0004-6256}} {{Jupiter radius|link=y}}
| mass = {{val|1.47|0.076|0.069}}{{Cite journal|bibcode=2017AJ....153...78C|title=Transit Timing Variation Measurements of WASP-12b and Qatar-1b: No Evidence for Additional Planets|last1=Collins|first1=Karen A|last2=Kielkopf|first2=John F|last3=Stassun|first3=Keivan G|journal=The Astronomical Journal|year=2017|volume=153|issue=2|page=78|doi=10.3847/1538-3881/153/2/78|arxiv=1512.00464|s2cid=55191644 |doi-access=free }} {{Jupiter mass|link=y}}
| density = {{cvt|266|kg/m3|g/cm3|lk=on|disp=out}}
| surface_grav = {{val|3.004|0.015}} g
| single_temperature = {{val|3128|64|68|u=K}} ({{val|2885|64|68|u=°C}}, {{val|5225|147|155|u=°F}}){{citation|arxiv=2102.00052|title=Phase curve and variability analysis of WASP-12b using TESS photometry|year=2021|doi=10.1093/mnrasl/slab014|last1=Owens|first1=Niall|last2=De Mooij|first2=E J W.|last3=Watson|first3=C. A.|last4=Hooton|first4=M. J.|journal=Monthly Notices of the Royal Astronomical Society: Letters|volume=503|pages=L38–L46|doi-access=free }}
}}
WASP-12b is a hot Jupiter{{Cite web|last=Starr|first=Michelle|title=Astronomers Just Found a 'Hot Jupiter' So Dark, It Absorbs Nearly 99% of Light|url=https://www.sciencealert.com/hot-jupiter-wasp-104b-one-of-the-darkest-planets-ever|website=ScienceAlert|date=April 23, 2018 }} (a class of extrasolar planets) orbiting the star WASP-12, discovered in April of 2008, by the SuperWASP planetary transit survey.{{cite web|url=http://wasp-planets.net/wasp-planets/|title=WASP Planets|work=SuperWASP|date=December 5, 2013|access-date=2016-01-26}} The planet takes only a little over one Earth day to orbit its star, in contrast to about 365.25 days for the Earth to orbit the Sun. Its distance from the star (approximately {{Convert|3.5|e6km|e6mi AU|disp=sqbr|abbr=off|sigfig=2|sp=us|lk=on}}) is only the Earth's distance from the Sun, with an eccentricity the same as Jupiter's. Consequently, it has one of the lowest densities for exoplanets ("inflated" by the flux of energy from the star). On December 3, 2013, scientists working with the Hubble Space Telescope (HST) reported detecting water in the atmosphere of the exoplanet.{{cite web |author=Staff |title=Hubble Traces Subtle Signals of Water on Hazy Worlds |url=http://www.nasa.gov/content/goddard/hubble-traces-subtle-signals-of-water-on-hazy-worlds/|publisher=NASA |date=3 December 2013|access-date=4 December 2013}}{{cite journal |last1=Mandell |first1=Avi M. |last2=Haynes |first2=Korey |last3=Sinukoff |first3=Evan |last4=Madhusudhan |first4=Nikku |last5=Burrows |first5=Adam |last6=Deming |first6=Drake |title=Exoplanet Transit Spectroscopy Using WFC3: WASP-12 b, WASP-17 b, and WASP-19 b |date=3 December 2013 |journal=Astrophysical Journal |volume=779 |issue=2 |page=128 |doi=10.1088/0004-637X/779/2/128 |arxiv = 1310.2949 |bibcode = 2013ApJ...779..128M |s2cid=52997396 }} In July 2014, NASA announced finding very dry atmospheres on three exoplanets (HD 189733b, HD 209458b, WASP-12b) orbiting sun-like stars.{{cite web |last1=Harrington |first1=J.D. |last2=Villard |first2=Ray |title=RELEASE 14-197 - Hubble Finds Three Surprisingly Dry Exoplanets |url=http://www.nasa.gov/press/2014/july/hubble-finds-three-surprisingly-dry-exoplanets/
|date=July 24, 2014 |work=NASA |access-date=July 25, 2014 }}
In September 2017, researchers working on the HST announced that WASP-12b reflects just 6% of the light that shines on its surface. As a result, the exoplanet has been described as "black as asphalt" and as "pitch black."{{cite news |last=Wall |first= Mike |date=18 September 2017 |title= The hellish world WASP-12b is darker than fresh asphalt in visible light, but glows red-hot in infrared|url=https://www.scientificamerican.com/article/astronomers-discover-pitch-black-exoplanet/ |work=Scientific American |access-date=19 September 2017 }}
Characteristics
File:The Pitch-Black Exoplanet WASP-12b.jpg
Since hot Jupiter exoplanets are tidally locked, one side is in permanent day while the other side is in permanent night, just as the same side of the Moon always faces the Earth. This is thought to induce a large flow of heat from the highly irradiated day side to the cooler night side, resulting in strong winds rushing around the planet's atmosphere.
Taylor Bell and Nicolas Cowan have pointed out that hydrogen will tend to be ionised on the day side. After flowing to the cooler face in a wind, it will then tend to recombine into neutral atoms, and thus will enhance the transport of heat.
The planet is so close to its star that its tidal forces are distorting it into an egg shape and pulling away its atmosphere at a rate of about 10−7 {{Jupiter mass|link=y}} (about 189 quadrillion tons) per year (6 billion tons per second).{{Cite journal |first1=Shu-lin |last1=Li |first2=N. |last2=Miller |first3=Douglas N. C. |last3=Lin |name-list-style=amp |first4=Jonathan J. |last4=Fortney |date=2010 |title=WASP-12b as a prolate, inflated and disrupting planet from tidal dissipation |journal=Nature |volume=463 |issue=7284 |pages=1054–1056 |doi=10.1038/nature08715 |pmid=20182506 |bibcode = 2010Natur.463.1054L |arxiv = 1002.4608 |s2cid=4414948 }} The so-called "tidal heating", and the proximity of the planet to its star, combine to bring the surface temperature to more than {{convert|2500|K|°C|-2}}.
On May 20, 2010, the Hubble Space Telescope spotted WASP-12b being "consumed" by its star. Scientists had been aware that stars could consume planets; however, this was the first time such an event had been observed so clearly. It has been estimated that the planet has between 3 and 10 million years left of its life.[http://www.nasa.gov/mission_pages/hubble/science/planet-eater.html Hubble Finds a Star Eating a Planet] nasa.gov. 2010-05-20. Retrieved on 2010-12-10.
The Hubble Space Telescope observed the planet by using its Cosmic Origins Spectrograph (COS). The observations have confirmed predictions published in Nature in February 2009 by Peking University's Shu-lin Li. The planet's atmosphere has ballooned to be nearly three times the radius of Jupiter, while the planet itself has 40% more mass than Jupiter.
Orbit
A study in 2012, utilizing the Rossiter–McLaughlin effect, determined that WASP-12b's orbit is strongly misaligned with the equatorial plane of its star by 59{{±|15|20}}°.{{citation|arxiv=1206.6105|title=Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments|year=2012|doi=10.1088/0004-637X/757/1/18|last1=Albrecht|first1=Simon|last2=Winn|first2=Joshua N.|last3=Johnson|first3=John A.|last4=Howard|first4=Andrew W.|last5=Marcy|first5=Geoffrey W.|last6=Butler|first6=R. Paul|last7=Arriagada|first7=Pamela|last8=Crane|first8=Jeffrey D.|last9=Shectman|first9=Stephen A.|last10=Thompson|first10=Ian B.|last11=Hirano|first11=Teruyuki|last12=Bakos|first12=Gaspar|last13=Hartman|first13=Joel D.|journal=The Astrophysical Journal|volume=757|issue=1|page=18|bibcode=2012ApJ...757...18A|s2cid=17174530}}
A study from 2019 found that the time interval between two transits has decreased by 29 ± 2 msec/year since the discovery in 2008. The value was updated in 2020 to 32.53{{±|1.62}} msec/year, giving WASP-12b an estimated lifetime of 2.90{{±|0.14}} million years.{{citation|arxiv=2012.02211|title=Decaying Orbit of the Hot Jupiter WASP-12b: Confirmation with TESS Observations|year=2021|last1=Turner|first1=Jake D.|last2=Ridden-Harper|first2=Andrew|last3=Jayawardhana|first3=Ray|journal=The Astronomical Journal|volume=161|issue=2|page=72|doi=10.3847/1538-3881/abd178|bibcode=2021AJ....161...72T|s2cid=227305717 |doi-access=free }} The study came to the conclusion that the orbit of WASP-12b is decaying as a result of tidal interactions between the planet and the host star WASP-12. Due to this decay, the orbital period will get shorter and the planet will get closer to the host star, until it will become part of the star. The decay is much faster than the decay of WASP-19b, which does not show a decay with current data.{{Cite web|url=https://wasp-planets.net/2019/11/26/the-orbit-of-wasp-12b-is-decaying/|title=The orbit of WASP-12b is decaying|last=waspplanets|date=2019-11-26|website=WASP Planets|language=en|access-date=2020-01-01}}{{cite journal|last1=Yee|first1=Samuel W.|last2=Winn|first2=Joshua N.|last3=Knutson|first3=Heather A.|last4=Patra|first4=Kishore C.|last5=Vissapragada|first5=Shreyas|last6=Zhang|first6=Michael M.|last7=Holman|first7=Matthew J.|last8=Shporer|first8=Avi|last9=Wright|first9=Jason T.|date=2019-11-20|title=The Orbit of WASP-12b is Decaying|journal=The Astrophysical Journal|volume=888|pages=L5|arxiv=1911.09131|doi=10.3847/2041-8213/ab5c16|s2cid=208202070 |doi-access=free }} In 2022, the decay rate was further refined to 29.81{{±|0.94}} msec/year, which corresponds to an estimated lifetime of {{val|3.16|0.10|ul=Myr}}.{{cite journal |last1=Wong |first1=Ian |last2=Shporer |first2=Avi |last3=Vissapragada |first3=Shreyas |last4=Greklek-McKeon |first4=Michael |last5=Knutson |first5=Heather A. |last6=Winn |first6=Joshua N. |last7=Benneke |first7=Björn |title=TESS Revisits WASP-12: Updated Orbital Decay Rate and Constraints on Atmospheric Variability |journal=The Astronomical Journal |date=20 January 2022 |volume=163 |issue=4 |page=175 |doi=10.3847/1538-3881/ac5680 |arxiv=2201.08370 |bibcode=2022AJ....163..175W |s2cid=246063389 |doi-access=free }}
=Carbon content=
Evidence reported in a 2010 study indicates that WASP-12b has an enhanced carbon-to-oxygen ratio, significantly higher than that of the Sun, indicating that it is a carbon-rich gas giant. The C/O ratio compatible with observations is about 1, while the solar value is 0.54. The C/O ratios suggest that carbon-rich planets may have formed in the star system.{{Cite journal | last1 = Madhusudhan | first1 = N. | last2 = Harrington | first2 = J. | last3 = Stevenson | first3 = K. B. | last4 = Nymeyer | first4 = S. | last5 = Campo | first5 = C. J. | last6 = Wheatley | first6 = P. J. | last7 = Deming | first7 = D. | last8 = Blecic | first8 = J. | last9 = Hardy | first9 = R. A. | doi = 10.1038/nature09602 | last10 = Lust | first10 = N. B. | last11 = Anderson | first11 = D. R. | last12 = Collier-Cameron | first12 = A. | last13 = Britt | first13 = C. B. T. | last14 = Bowman | first14 = W. C. | last15 = Hebb | first15 = L. | last16 = Hellier | first16 = C. | last17 = Maxted | first17 = P. F. L. | last18 = Pollacco | first18 = D. | last19 = West | first19 = R. G. | title = A high C/O ratio and weak thermal inversion in the atmosphere of exoplanet WASP-12b | journal = Nature | volume = 469 | issue = 7328 | pages = 64–67 | year = 2010 | pmid = 21150901|bibcode = 2011Natur.469...64M |arxiv = 1012.1603 | s2cid = 4415171 }}
One of the researchers behind that study commented that "with more carbon than oxygen, you would get rocks of pure carbon, such as diamond or graphite".{{cite magazine | url = https://www.usnews.com/science/articles/2010/12/10/carbon-rich-planet-a-girls-best-friend.html | title = Carbon-Rich Planet: A Girl's Best Friend? | date = 10 December 2010 | magazine = U.S. News & World Report}}
The published study states, "Although carbon-rich giant planets like WASP-12b have not been observed, theory predicts myriad compositions for carbon-dominated solid planets. Terrestrial-sized carbon planets, for instance, could be dominated by graphite or diamond interiors, as opposed to the silicate composition of Earth." These remarks have led the media to pick up on the story,{{cite news | url = https://www.thestar.com/article/905303--carbon-rich-planet-could-house-diamonds | title = Carbon-rich planet could house diamonds | author = Lorianna De Giorgio | date = 10 December 2010 | newspaper = Toronto Star
}} some even calling WASP-12b a "diamond planet".{{cite news | title = Diamond planet found by Keele University astronomers | url = http://news.bbc.co.uk/local/stoke/hi/people_and_places/nature/newsid_9272000/9272801.stm | date = 9 December 2010 | work = BBC News Online}}
The carbon content of the planet is located within its atmosphere, in the form of carbon monoxide and methane. The study appears in the journal Nature.{{Cite news|title=Exoplanet Strikes Carbon Pay Dirt|url=http://www.scientificamerican.com/podcast/episode.cfm?id=exoplanet-strikes-carbon-paydirt-10-12-09|newspaper=Scientific American|date=December 9, 2010|first=Christopher| last=Intagliata}}
File:Clear to cloudy hot Jupiters.jpg" exoplanets - from top left to lower right: WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b.]]
File:WASP-12b (NASA).jpg|WASP-12b and its host star, WASP-12 (artist conception).
File:WASP-12b a Hot, Carbon-Rich Planet.jpg|Hot, carbon-rich planet WASP-12b and its host star. (Exoplanet color was unknown at the time of this artist conception).
File:WASP-12b.jpg|WASP-12b and its host star, WASP-12 − with IR spectra noting the presence of various chemical molecules.
Candidate satellite
Russian astronomers studying a curve of change of shine of the planet observed regular variation of light that may arise from plasma torus surrounding at least one exomoon in orbit around WASP-12b.[http://www.ria.ru/science/20120206/558647431.html Российские астрономы впервые открыли луну возле экзопланеты] (in Russian) - "Studying of a curve of change of shine of WASP-12b has brought to the Russian astronomers unusual result: regular splashes were found out.<...> Though stains on a star surface also can cause similar changes of shine, observable splashes are very similar on duration, a profile and amplitude that testifies for benefit of exomoon existence." This is not expected, as hot Jupiter-type planets are expected to lose large moons within geologically short timescales.{{cite journal | bibcode = 2002ApJ...575.1087B | title=Stability of Satellites around Close-in Extrasolar Giant Planets | journal=The Astrophysical Journal | volume=575 | issue=2 | pages=1087–1093 | year=2002 | last1=Barnes | first1=Jason W. | last2=O'Brien | first2=D. P. | doi=10.1086/341477|arxiv = astro-ph/0205035 | s2cid=14508244 }} The satellite in question could instead be a Trojan body.{{citation|arxiv=1605.02507|title=On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source|year=2016|doi=10.1093/mnras/stw1110|last1=Kislyakova|first1=K. G.|last2=Pilat-Lohinger|first2=E.|last3=Funk|first3=B.|last4=Lammer|first4=H.|last5=Fossati|first5=L.|last6=Eggl|first6=S.|last7=Schwarz|first7=R.|last8=Boudjada|first8=M. Y.|last9=Erkaev|first9=N. V.|journal=Monthly Notices of the Royal Astronomical Society|volume=461|issue=1|pages=988–999|doi-access=free |bibcode=2016MNRAS.461..988K|s2cid=119205132}}
See also
- TrES-2b, another planet that absorbs over 90% of light.
- BPM 37093, a carbon-rich star.
- Wide Angle Search for Planets
References
{{reflist|refs=
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External links
{{commons category-inline|WASP-12 b|WASP-12b}}
- [http://wasp-planets.net/wasp-planets/ SuperWASP Wide Angle Search for Planets: The Planets], SuperWASP.
- [https://www.newscientist.com/article/dn14943-starhugging-planet-is-hottest-and-fastest-found.html?DCMP=ILC-hmts&nsref=news2_head_dn14943 Star-hugging planet is hottest and fastest found], New Scientist.
- [http://news.bbc.co.uk/1/hi/science_and_environment/10136415.stm BBC News - Hubble spots a planet-eating star]
- [http://www.perseus.gr/Astro-Photometry-WASP-12-20110114.htm WASP-12b in transit (lightcurve)]
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Category:Exoplanets discovered by WASP