View source for WASP-4

{{Short description|G-type main sequence star in the constellation Phoenix}}
{{Starbox begin
| name = WASP-4
}}
{{Starbox image
| image = [[File:Planet WASP-4.png|250px|center]]
| caption = Artistic rendering of WASP-4 b
}}
{{Starbox observe
| epoch = J2000.0
| constell = [[Phoenix (constellation)|Phoenix]]<ref name="Roman1987"/>
| ra = {{RA|23|34|15.0857}}<ref name="GaiaDR3"/>
| dec = {{DEC|−42|03|41.048}}<ref name="GaiaDR3"/>
| appmag_v = {{val|12.468|0.025}}<ref name="APASS DR9"/>
}}
{{Starbox character
| type = [[Main sequence]]
| class = G7V<ref name="Wilson2008"/>
| appmag_1_passband = V
| appmag_1 = {{val|12.468|0.025}}<ref name="APASS DR9"/>
| appmag_2_passband = B
| appmag_2 = {{val|13.216|0.020}}<ref name="APASS DR9"/>
| variable = [[Variable star#Planetary transits|Planetary transit variable]]<ref name="Wilson2008"/>
}} 
{{Starbox astrometry
| radial_v = {{val|57.61|0.76}}<ref name="GaiaDR3"/>
| prop_mo_ra = {{val|9.950|(12)}}
| prop_mo_dec = {{val|−87.620|(10)}}
| pm_footnote = <ref name="GaiaDR3"/>
| parallax = 3.6623
| p_error = 0.0147
| parallax_footnote = <ref name="GaiaDR3"/>
| absmag_v =
}}
{{Starbox detail
| mass = {{val|0.899|0.033|0.031}}<ref name=Basturk2025/>
| radius = {{val|0.9150|0.0089|0.0091}}<ref name=Basturk2025/>
| gravity = {{Val|4.472|0.013|0.012}}<ref name=Basturk2025/>
| temperature = {{val|5488|29|28}}<ref name=Basturk2025/>
| metal_fe = {{val|-0.050|0.040}}<ref name="Bonomo2017"/>
| rotation = {{val|22.2|3.3}}<ref name="Bonomo2017"/> days
| rotational_velocity = {{val|2.2|0.6|1.0}}<ref name="Bonomo2017"/>
| age_gyr = {{val|7.0|2.9}}<ref name="Bonomo2017"/>
}}
{{Starbox catalog
| names = {{odlist | name=[[SuperWASP|1SWASP]] J233415.06-420341.1 | 2MASS=J23341508-4203411 | TIC=402026209 | TOI=232 | TYC=8017-108-1 | WASP=4}}<ref name="Simbad"/> 
}}
{{Starbox reference
| Simbad = WASP-4
| NSTED = WASP-4
}}
{{Starbox end}}

'''WASP-4''' is a [[G-type main-sequence star]] approximately 891 [[light-year]]s away in the [[constellation]] of [[Phoenix (constellation)|Phoenix]].<ref name="Wilson2008"/><ref name="Roman1987"/><ref name="GaiaDR3"/> Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by a giant planet on a close orbit.<ref name=Maxted2015/>

==Planetary system==
In 2007 the [[exoplanet]] [[WASP-4b]] was discovered orbiting this star. With an orbital period of just 1.3 days, it is classified as a [[hot Jupiter]].<ref name="Wilson2008"/> The planet's orbital period appears to be decreasing at a rate of {{val|7.33|0.71}} milliseconds per year, suggesting that its orbit is decaying, with a decay timescale of 15.77{{±|1.57}} million years. Another [[super-Jupiter|superjovian]] planet in the system is suspected.<ref name=Turner2021/> The orbital decay was confirmed in a 2025 study.<ref name=Basturk2025/>

{{OrbitboxPlanet begin
| table_ref = <ref name=Basturk2025/>
}}
{{OrbitboxPlanet
| exoplanet = [[WASP-4b|b]]
| mass = {{val|1.200|0.032|0.030}}
| semimajor = {{val|0.02294|0.00028|0.00026}}
| period = {{val|1.338230994|(84)}}
| eccentricity = {{Val|0.0013|0.0005|0.0009}}
| inclination = {{val|88.05|0.85|0.53}}
| radius = {{val|1.349|0.011|0.012}}
}}
{{OrbitboxPlanet hypothetical
| exoplanet = c
| mass = {{val|5.47|0.44|p=≥}}
| semimajor = {{val|6.82|0.25}}
| period = {{val|7001.0|6.6}}
| eccentricity = 
| inclination = 
| radius = 
}}
{{Orbitbox end}}

==See also==
* [[SuperWASP]]
* [[List of extrasolar planets]]

==References==
{{reflist|refs=

<ref name="Simbad">{{cite simbad | title=WASP-4 | access-date=2018-09-22 }}</ref>

<ref name="GaiaDR3">{{Cite Gaia DR3|6535499658122055552}}</ref>

<ref name="APASS DR9">{{cite journal | title=VizieR Online Data Catalog: AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016) | last1=Henden | first1=A. A. | last2=Templeton | first2=M. | last3=Terrell | first3=D. | last4=Smith | first4=T. C. | last5=Levine | first5=S. | last6=Welch | first6=D. | display-authors=1 | journal=VizieR On-line Data Catalog: II/336. Originally Published in: 2015AAS...22533616H | volume=2336 | year=2016 | bibcode=2016yCat.2336....0H }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=II/336/apass9&recno=58061720 Vizier catalog entry ]</ref>

<ref name=Basturk2025>{{Cite journal |last=Baştürk |first=Ö |last2=Kutluay |first2=A. C. |last3=Barker |first3=A. |last4=Yalçınkaya |first4=S. |last5=Southworth |first5=J. |last6=Barkaoui |first6=K. |last7=Wünsche |first7=A. |last8=Burgdorf |first8=M. J. |last9=Timmermans |first9=M. |date=2025-06-17 |title=The Orbit of WASP-4 b is in Decay |arxiv=2506.15022 |journal=[[Monthly Notices of the Royal Astronomical Society]] }}</ref>

<ref name="Roman1987">{{Cite constellation|WASP-4}}</ref>

<ref name="Wilson2008">{{cite journal | title=WASP-4b: A 12th Magnitude Transiting Hot Jupiter in the Southern Hemisphere | last1=Wilson | first1=D. M. | last2=Gillon | first2=M. | last3=Hellier | first3=C. | last4=Maxted | first4=P. F. L. | last5=Pepe | first5=F. | last6=Queloz | first6=D. | last7=Anderson | first7=D. R. | last8=Collier Cameron | first8=A. | last9=Smalley | first9=B. | last10=Lister | first10=T. A. | last11=Bentley | first11=S. J. | last12=Blecha | first12=A. | last13=Christian | first13=D. J. | last14=Enoch | first14=B. | last15=Haswell | first15=C. A. | last16=Hebb | first16=L. | last17=Horne | first17=K. | last18=Irwin | first18=J. | last19=Joshi | first19=Y. C. | last20=Kane | first20=S. R. | last21=Marmier | first21=M. | last22=Mayor | first22=M. | last23=Parley | first23=N. | last24=Pollacco | first24=D. | last25=Pont | first25=F. | last26=Ryans | first26=R. | last27=Segransan | first27=D. | last28=Skillen | first28=I. | last29=Street | first29=R. A. | last30=Udry | first30=S. | display-authors=1 | journal=The Astrophysical Journal Letters | volume=675 | issue=2 | pages=L113–L116 | year=2008 | arxiv=0801.1509 | bibcode=2008ApJ...675L.113W | bibcode-access=free | doi=10.1086/586735 | doi-access=free | s2cid=10823235 }}</ref>

<ref name=Maxted2015>{{citation|arxiv=1503.09111|title=A comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars|year=2015|doi=10.1051/0004-6361/201525774|last1=Maxted|first1=P. F. L.|last2=Serenelli|first2=A. M.|last3=Southworth|first3=J.|s2cid=53324330|journal=Astronomy & Astrophysics|volume=577|pages=A90|bibcode=2015A&A...577A..90M}}</ref>

<ref name="Bonomo2017">{{cite journal |last1=Bonomo |first1=A. S. |last2=Desidera |first2=S. |display-authors=etal |date=June 2017 |title=The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets |journal=[[Astronomy & Astrophysics]] |volume=602 |issue= |pages=A107 |doi=10.1051/0004-6361/201629882 |arxiv=1704.00373 |bibcode=2017A&A...602A.107B}}</ref>

<ref name=Turner2021>{{citation|arxiv=2112.09621|year=2022|title=Characterizing the WASP-4 System with TESS and Radial Velocity Data: Constraints on the Cause of the Hot Jupiter's Changing Orbit and Evidence of an Outer Planet|doi=10.3847/1538-3881/ac686f |last1=Turner |first1=Jake D. |last2=Flagg |first2=Laura |last3=Ridden-Harper |first3=Andrew |last4=Jayawardhana |first4=Ray |journal=The Astronomical Journal |volume=163 |issue=6 |page=281 |bibcode=2022AJ....163..281T |s2cid=245329747 |doi-access=free }}</ref>

}}

==External links==
* {{cite web |url=http://www.superwasp.org/ |title=SuperWASP Homepage |access-date=2008-07-02 |archive-url=https://web.archive.org/web/20021208111324/http://www.superwasp.org/ |archive-date=2002-12-08 |url-status=dead }}
* {{cite web |url=http://www.superwasp.org/press_release2/WASP2007_national_pressV5.pdf |archive-url=https://web.archive.org/web/20080516083642/http://www.superwasp.org/press_release2/WASP2007_national_pressV5.pdf |url-status=dead |archive-date=2008-05-16 |title=UK planet hunters announce three new finds |access-date=2008-07-02 |date=2007-10-30 }}
{{Clear}}

{{Sky|23|34|15.06|-|42|03|41.1|1000}}

{{Stars of Phoenix}}

[[Category:Phoenix (constellation)]]
[[Category:G-type main-sequence stars]]
[[Category:Planetary systems with one confirmed planet]]
[[Category:Planetary transit variables]]
[[Category:Wide Angle Search for Planets|4]]
[[Category:2MASS objects|J23341508-4203411]]
[[Category:TESS Objects of Interest|232]]
[[Category:TIC objects|402026209]]
{{variable-star-stub}}