View source for WASP-24b

{{short description|Hot Jupiter exoplanet orbiting WASP-24}}
{{Infobox planet
| name                     = WASP-24b
<!-- DISCOVERY           -->
| discoverer               = Street ''et al.''<ref name="Street2010"/>
| discovery_site           = [[La Silla Observatory|La Silla]]/[[Roque de los Muchachos Observatory|ORM]]
| discovered               = April 13, 2010
| discovery_method         = [[Doppler spectroscopy]]<ref name="Street2010"/>
<!-- DESIGNATIONS        -->
<!-- ORBITAL             --> 
| epoch                    = J2000
| apsis                    = astron
| semimajor                = {{convert|0.0359|AU|km|abbr=on}}
| period                   = 2.3412083<ref name=EPE/> [[day|d]]
| inclination              = 83.64
| star                     = [[WASP-24]]
<!-- PHYS CHARS          --> 
| mean_radius              = 1.104<ref name=EPE/> {{Jupiter radius|link=y}}
| mass                     = 1.032<ref name=EPE/> {{Jupiter mass|link=y}}
| density                  = 768 {{±|0.126|0.096}}<ref name="Street2010"/> [[gram|g]] [[cubic centimetre|cm<sup>−3</sup>]]
| single_temperature       = 1660 {{±|44|42}}<ref name="Street2010"/>
<!-- ATMOSPHERE          --> 
<!-- NOTES               --> 
}}
'''WASP-24b''' is a [[Hot Jupiter]] detected in the orbit of the [[Stellar classification#Class F|F-type]] star [[WASP-24]]. The planet is approximately the same size and mass of Jupiter, but it orbits at approximately 4% of the mean distance between the Earth and the Sun every two days. WASP-24b was observed by [[SuperWASP]] starting in 2008; after two years of observations, follow-ups led to the collection of the information that led to the planet's discovery.

==Discoveries==
Between March 5, 2008, and March 9, 2009, WASP-24 was under the observation of both the Northern and Southern branches of the [[SuperWASP]] project, a ground-based consortium aiming to discover planets that [[transit method|transit]] (cross in front of) their host stars with respect to Earth. 9,750 data points were collected for the light curve; the star was flagged as host to possible transit events, prompting a team of astronomers from Europe and the United States to conduct follow-up observations.<ref name="Street2010"/>

The [[Fibre-Fed Echelle Spectrograph]] (FIES) on the [[Roque de los Muchachos Observatory]]'s [[Nordic Optical Telescope]] provided [[radial velocity]] measurements for the system; additional calibrations during the observational period also provided the spectrum of the star. Ten [[Doppler spectroscopy]] observations were collected between December 31, 2008, and April 10, 2009. Follow-ups between January 29, 2009, and July 26, 2009, were conducted using the [[CORALIE spectrograph]] on the [[Leonhard Euler Telescope]] at [[La Silla Observatory]], broadening knowledge of the star's spectrum, and collecting additional radial velocity measurements. These observations revealed that a body of planetary mass was orbiting the star. Analysis of the data led to the rejection of other [[false positive]] scenarios, and later, to the confirmation of the planet WASP-24b.<ref name="Street2010"/>

Because of the star's position in the sky, WASP-24 was visible to both the [[Faulkes Telescope North]] on Maui and the [[Faulkes Telescope South]] in Australia. The telescopes were used to observe the star's light, thereby detecting times when WASP-24b might have transited its star. The Faulkes telescopes collected data on two complete transits and one partial one. During this period, a nearby [[eclipsing binary]] star called N1 was considered and avoided to avoid contaminating the collected light samples.<ref name="Street2010"/>

Information collected by the Faulkes telescopes was extrapolated to reveal the characteristics of the star, and from there of the planet. The planet's discoverers compared it to [[HD 189733 b]], which resembles WASP-24b in [[orbital period|orbit length]], mass, and radius.<ref name=Street2010 /> The planet's discovery was first reported on the SuperWASP website.<ref name=EPEcatalog/>

==Host star==
{{main|WASP-24}}
WASP-24 is a [[Stellar classification#Class F|F-type]] star located 340 [[parsec]]s (1,100 [[light year]]s) away. The star is an estimated 1.129 times the [[solar mass|mass]] of the Sun. WASP-24 is also 1.147 times the [[solar radius|radius]] of the star, making the star both larger and more massive than the Sun. WASP-24 has an [[effective temperature]] of 6100 [[Kelvin scale|K]], hotter than the Sun.<ref name="Torres2012"/> WASP-24 has a [[metallicity]] similar to that measured in the Sun.<ref name="Torres2012"/> The star's estimated age is 3.8 billion years old, although the star's age is not well-constrained.<ref name="Street2010"/>

WASP-24 has an [[apparent magnitude]] of 11.3. It cannot be seen from Earth with the [[naked eye]].<ref name=EPE/>

==Characteristics==
WASP-24b is a [[Hot Jupiter]] that has a mass of 1.032 times the [[Jupiter mass|mass]] of Jupiter. Its radius is 1.104 times the [[Jupiter radius|radius]] of Jupiter. In addition, with a [[semimajor axis|mean distance]] of 0.0359 [[astronomical unit|AU]] between it and its star, where one AU is the average distance between the Earth and the Sun, WASP-24b completes an orbit every 2.3412083 days (roughly 57 hours).<ref name=EPE /> In comparison, [[Mercury (planet)|Mercury]] orbits the Sun every 87.97 days at a distance of 0.387 AU.<ref name=Mercury />

WASP-24b's [[orbital inclination]] is 83.64º, placing WASP-24b almost edge-on with respect to Earth and to its host star.<ref name=EPE />

The study in 2012, utilizing a [[Rossiter–McLaughlin effect]], have determined the planetary orbit is well aligned with the equatorial plane of the star, misalignment equal to -4.7{{±|4}}°.<ref>{{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 }}</ref>

==References==
{{reflist|refs=

<ref name=EPEcatalog>{{cite web | url=https://exoplanet.eu/catalog/ | title=Interactive Extra-solar Planets Catalogue - Candidates detected by radial velocity or astrometry |author=Jean Schneider | date=2011 | work=[[Extrasolar Planets Encyclopaedia]] | access-date=30 May 2011 }}</ref>

<ref name=Mercury>{{cite web | url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html | title=Mercury Fact Sheet | author=David Williams | date=2004 | work=[[Goddard Space Flight Center]] | publisher=[[NASA]] | accessdate=30 May 2011 }}</ref>

<ref name=EPE>{{cite web | url=http://www.exoplanet.eu/star.php?st=WASP-24 | archive-url=https://web.archive.org/web/20100421200029/http://exoplanet.eu/star.php?st=WASP-24 | url-status=dead | archive-date=April 21, 2010 | title=Notes on star WASP-24 | author=Jean Schneider | date=2010 | work=[[Extrasolar Planets Encyclopaedia]] | access-date=30 May 2011 }}</ref>

<ref name="Street2010">{{cite journal | title=WASP-24 b: A New Transiting Close-in Hot Jupiter Orbiting a Late F-star | last1=Street | first1=R. A. W. | last2=Simpson | first2=E. | last3=Barros | first3=S. C. C. | last4=Pollacco | first4=D. | last5=Joshi | first5=Y. | last6=Todd | first6=I. | last7=Collier Cameron | first7=A. | last8=Enoch | first8=B. A. | last9=Parley | first9=N. | last10=Stempels | first10=E. | last11=Hebb | first11=L. | last12=Triaud | first12=A. H. M. J. | last13=Queloz | first13=D. | last14=Segransan | first14=D. | last15=Pepe | first15=F. | last16=Udry | first16=S. | last17=Lister | first17=T. A. | last18=Depagne | first18=É. | last19=West | first19=R. G. | last20=Norton | first20=A. J. | last21=Smalley | first21=B. | last22=Hellier | first22=C. | last23=Anderson | first23=D. R. | last24=Maxted | first24=P. F. L. | last25=Bentley | first25=S. J. | last26=Skillen | first26=I. | last27=Gillon | first27=M. | last28=Wheatley | first28=P. | last29=Bento | first29=J. | last30=Cathaway-Kjontvedt | first30=P. | last31=Christian | first31=D. J. | display-authors=1 |  journal=The Astrophysical Journal | volume=720 | issue=1 | pages=337–343 | year=2010 | bibcode=2010ApJ...720..337S | doi=10.1088/0004-637X/720/1/337 | hdl=10211.3/172030 | s2cid=6745500 | hdl-access=free }}</ref>

<ref name="Torres2012">{{cite journal | title=Improved Spectroscopic Parameters for Transiting Planet Hosts | last1=Torres | first1=Guillermo | last2=Fischer | first2=Debra A. | last3=Sozzetti | first3=Alessandro | last4=Buchhave | first4=Lars A. | last5=Winn | first5=Joshua N. | last6=Holman | first6=Matthew J. | last7=Carter | first7=Joshua A. | display-authors=1 | journal=The Astrophysical Journal | volume=757 | issue=2 | at=161 | year=2012 | arxiv=1208.1268 | bibcode=2012ApJ...757..161T | doi=10.1088/0004-637X/757/2/161 | s2cid=16580774 }}</ref>

}}

{{Virgo (constellation)}}
[[Category:Exoplanets discovered in 2010]]
[[Category:Hot Jupiters]]
[[Category:Virgo (constellation)]]
[[Category:Exoplanets discovered by WASP]]