View source for XO-3b

{{Short description|Extrasolar planet in the constellation Camelopardalis}}
{{Infobox planet
| name                     = XO-3b <ref name="Krull2008"/>
| image                    = Exoplanet Comparison XO-3 b.png
| caption                  = Size comparison of XO-3b with Jupiter.
<!-- DISCOVERY           -->
| discovery_ref            = <ref name="Krull2008"/><ref name="Rice"/>
| discoverer               = [[XO Project]]
| discovery_site           = [[XO telescope]] [[Maui]], [[Hawaii]]
| discovered               = May 30, 2007
| discovery_method         = Transit,<br>Radial velocity
<!-- DESIGNATIONS        -->
<!-- ORBITAL             --> 
| apsis                    = astron
| semimajor                = {{convert|0.0454|±|0.00082|AU|km|abbr=on}}<ref name="Winn2008"/>
| eccentricity             = 0.2883 ± 0.0025<ref name="Hirano2011"/>
| period                   = 3.1915289 ± 0.0000032<ref name="Winn2009"/> [[day|d]]
| inclination              = 84.20 ± 0.54<ref name="Winn2008"/>
| arg_peri                 = 346.1{{±|1.2|1.1}}<ref name="Hirano2011"/>
| semi-amplitude           = 1494.0 ± 9.5<ref name="Hirano2011"/>
| star                     = [[XO-3]]
<!-- PHYS CHARS          --> 
| mean_radius              = 1.217 ± 0.073<ref name="Winn2008"/> {{Jupiter radius|link=y}}
| mass                     = 11.79 ± 0.59<ref name="Winn2008"/> {{Jupiter mass|link=y}}
| albedo             = 0.106{{±|0.008|0.106}}<ref name=Dang2021>{{citation|arxiv=2111.03673|year=2022|title=Thermal Phase Curves of XO-3b: An Eccentric Hot Jupiter at the Deuterium Burning Limit|doi=10.3847/1538-3881/ac365f |last1=Dang |first1=Lisa |last2=Bell |first2=Taylor J. |last3=Cowan |first3=Nicolas B. |last4=Thorngren |first4=Daniel |last5=Kataria |first5=Tiffany |last6=Knutson |first6=Heather A. |last7=Lewis |first7=Nikole K. |last8=Stassun |first8=Keivan G. |last9=Fortney |first9=Jonathan J. |last10=Agol |first10=Eric |last11=Laughlin |first11=Gregory P. |last12=Burrows |first12=Adam |last13=Collins |first13=Karen A. |last14=Deming |first14=Drake |last15=Jovmir |first15=Diana |last16=Langton |first16=Jonathan |last17=Rastegar |first17=Sara |last18=Showman |first18=Adam P. |journal=The Astronomical Journal |volume=163 |issue=1 |page=32 |bibcode=2022AJ....163...32D |s2cid=243848020 |doi-access=free }}</ref>
| single_temperature = 1400-2000 [[Kelvin|K]]<ref name=Dang2021/>
<!-- ATMOSPHERE          --> 
<!-- NOTES               --> 
}}
'''XO-3b''' is an [[exoplanet]] with about 11.79 times the mass of [[Jupiter]], and it orbits its parent [[star]] [[XO-3]] in about 3.2 days.<ref name="space">{{Cite web |last=Bryner|first=Jeanna|date=2007-05-30 |title=Oddball Planet Puzzles Astronomers |url=https://www.space.com/3870-oddball-planet-puzzles-astronomers.html |access-date=2024-08-16 |website=Space.com |language=en}}</ref> The radius of this object is 1.217 times that of Jupiter. Astronomers announced their discovery on May 30, 2007, at the [[American Astronomical Society]] in [[Honolulu, Hawaii]]. Its discovery is attributed to the combined effort of amateur and professional astronomers working together on the [[XO Project]] using a [[telescope]] located on the Haleakala summit in Hawaii.<ref name="Rice"/>

Dubbed an "oddball" planet, at the time of its discovery the planet was the most massive planet found in close proximity to a star, yet the orbit is significantly elliptical instead of circular, as would be expected.<ref name="Rice"/> It is also considered a [[transiting planet]], passing in front of its parent star during each orbit. It is the third such planet to be found by the XO Project which was specifically created to locate them.<ref>{{Cite web |title=XO-3b: Supersized planet or oasis in the 'brown dwarf desert'? |url=https://www.eurekalert.org/news-releases/871295 |access-date=2024-08-16 |website=EurekAlert! |language=en}}</ref>

==Planetary orbit==
Measurements of the [[Rossiter–McLaughlin effect]] allow a determination of the angle between the planet's orbital plane and the equator of the parent star. Initial reports suggested this angle was very large, at 70 ± 15 degrees,<ref>{{cite journal | title=Misaligned spin-orbit in the XO-3 planetary system? | author=Hébrard, G. | display-authors=etal | journal=[[Astronomy and Astrophysics]] | volume=488 | issue=2 | date=2008 | pages=763–770 | bibcode=2008A&A...488..763H | doi=10.1051/0004-6361:200810056|arxiv = 0806.0719 | s2cid=18111249 }}([https://arxiv.org/abs/0806.0719 web preprint])</ref> which is significantly larger than that of the other transiting planets for which this measurement has been made.<ref>{{cite journal | title= Measuring accurate transit parameters | author=Joshua N. Winn |date=2008 | doi= 10.1017/S174392130802629X | journal= Proceedings of the International Astronomical Union | volume= 4 | pages= 99–109 | arxiv=0807.4929 | bibcode= 2009IAUS..253...99W| s2cid=34144676 }}</ref> The authors cautioned that [[systematic error|systematic]] effects may have affected the measurements, and a later determination by an independent group of astronomers determined a reduced value of 37.3{{±|3.0}}°.<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> This value is, however, still larger than the misalignment between the Sun's equator and the orbital plane of Jupiter, which is only 6°.<ref name="Winn2009"/>

The misalignment may indicate that in the past an encounter with another planet altered its orbit, kicking it out of the plane of the planetary system. Its [[orbital eccentricity]] is very large (''e''&nbsp;=&nbsp;0.2883). Since tidal forces should have reduced the orbital eccentricity of this planet it is possible that there is another massive planet outside the orbit of XO-3 that is in [[orbital resonance]] with XO-3b.<ref>{{cite news|url=https://www.newscientist.com/article/mg19926744.400-planets-strange-orbit-points-to-planetary-billiards.html|title=Planet's strange orbit points to planetary billiards|author=Powell, Devin|date=2008-09-22|work=[[New Scientist]]|access-date=2008-09-23}}</ref> Another planetary system that may have also undergone such planet–planet interactions is [[Upsilon Andromedae]].<ref>{{cite journal|url=http://simbad.u-strasbg.fr/cgi-bin/cdsbib?2005Natur.434..873F |author=Ford, E. |display-authors=etal |title=Planet-planet scattering in the upsilon Andromedae system |journal=[[Nature (journal)|Nature]] |volume=434 |pages=873–876 |date=2005 |doi=10.1038/nature03427 |pmid=15829958 |issue=7035 |arxiv=astro-ph/0502441 |bibcode=2005Natur.434..873F |s2cid=119496437 }}</ref>

Due to tidal dissipation, the planetary orbital period is decaying at a rate of {{val|6.2|0.29|e=-9}}, or about 1.7&nbsp;ms per orbit. At this rate, the planet will be engulfed by its star in about 1.4 million years. However, unlike the similar planet [[WASP-12b]], it is unlikely to be experiencing significant mass loss.<ref>{{citation|arxiv=2111.06551|year=2022|title=Transit Timing Variation of XO-3b: Evidence for Tidal Evolution of Hot Jupiter with High Eccentricity|doi=10.1088/1538-3873/ac495a |last1=Yang |first1=Fan |last2=Wei |first2=Xing |journal=Publications of the Astronomical Society of the Pacific |volume=134 |issue=1032 |page=024401 |bibcode=2022PASP..134b4401Y |s2cid=244102737 }}</ref><ref>{{citation|arxiv=2111.06678|year=2023|title=TESS Timings of 31 Hot Jupiters with Ephemeris Uncertainties|last1=Shan |first1=Su-Su |last2=Yang |first2=Fan |last3=Lu |first3=You-Jun |last4=Wei |first4=Xing |last5=Tian |first5=Wen-Wu |last6=Zhang |first6=Hai-Yan |last7=Guo |first7=Rui |last8=Cui |first8=Xiao-Hong |last9=Yang |first9=Ai-Yuan |last10=Zhang |first10=Bo |last11=Liu |first11=Ji-Feng |journal=The Astrophysical Journal Supplement Series |volume=264 |issue=2 |page=37 |doi=10.3847/1538-4365/aca65f |bibcode=2023ApJS..264...37S |s2cid=253236879 |doi-access=free }}</ref>

==Atmosphere==
Observations of several transits in the [[Ultraviolet#NUV|near ultraviolet]] by the [[Neil Gehrels Swift Observatory]] results in a measured planetary radius, in the near ultraviolet, of 2.54 times that of [[Jupiter]].<ref name="Corrales2021"/>

==Debate==
There is currently a debate over the classification of this object as either a [[planet]] or a [[brown dwarf]]. One of the leading astronomers in this discussion is [[Christopher Johns-Krull]], who indicated that the debate is still quite lively. This is not particularly unusual or strange, as it would not be the first of many brown dwarfs orbiting mother stars.<ref name="space" />

The light curve that best matches the steepness of ingress and egress implies a planetary radius of {{Jupiter radius|1.32 ± 0.15}} and a mass of {{Jupiter mass|11.71 ± 0.46}}.<ref name="Krull2008"/>

==See also==
* [[XO Telescope]]

==References==
{{Reflist|refs=

<ref name="Corrales2021">{{cite journal | last1=Corrales | first1= Lia | last2=Ravi | first2=Sasikrishna | last3=King | first3=George W. | last4=May | first4=Erin | last5=Rauscher | first5=Emily | last6=Reynolds | first6=Mark | display-authors=1 | title=Five New Hot Jupiter Transits Investigated with Swift-UVOT | journal=The Astronomical Journal | date=1 December 2021 | volume=162 | issue=6 | at=287 | arxiv=2110.01579 | bibcode=2021AJ....162..287C | bibcode-access=free | doi=10.3847/1538-3881/ac2c67 | doi-access=free }}</ref>

<ref name="Hirano2011">{{cite journal | title=Further Observations of the Tilted Planet XO-3: A New Determination of Spin-Orbit Misalignment, and Limits on Differential Rotation | last1=Hirano | first1=Teruyuki | last2=Narita | first2=Norio | last3=Sato | first3=Bun’ei | last4=Winn | first4=Joshua N. | last5=Aoki | first5=Wako | last6=Tamura | first6=Motohide | last7=Taruya | first7=Atsushi | last8=Suto | first8=Yasushi | display-authors=1 | journal=Publications of the Astronomical Society of Japan | date=2011 | volume=63 | issue=6 | pages=L57–L61 | arxiv=1108.4493 | bibcode=2011PASJ...63L..57H | doi=10.1093/pasj/63.6.l57}}</ref>

<ref name="Krull2008">{{cite journal | title=XO-3b: A Massive Planet in an Eccentric Orbit Transiting an F5V Star | last1=Johns-Krull | first1=Christopher M. | last2=McCullough | first2=Peter R. | last3=Burke | first3=Christopher J. | last4=Valenti | first4=Jeff A. | last5=Janes | first5=K. A. | last6=Heasley | first6=J. N. | last7=Prato | first7=L. | last8=Bissinger | first8=R. | last9=Fleenor | first9=M. | display-authors=1 | journal=The Astrophysical Journal | date=2008 | volume=677 | issue=1 | pages=657–670 | arxiv=0712.4283 | bibcode=2008ApJ...677..657J | bibcode-access=free | doi=10.1086/528950 | doi-access=free }}</ref>

<ref name="Rice">{{cite press release | title=XO-3b: Supersized planet or oasis in the 'brown dwarf desert'? | author=<!--Not stated--> | date=2007-06-30 | publisher=Rice University | location=Houston, Texas | url=https://news2.rice.edu/2007/05/30/xo-3b-supersized-planet-or-oasis-in-the-brown-dwarf-desert/ | access-date=2022-01-01 }}</ref>

<ref name="Winn2008">{{cite journal | title=The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b | last1=Winn | first1=Joshua N. | last2=Holman | first2=Matthew J. | last3=Torres | first3=Guillermo | last4=McCullough | first4=Peter | last5=Johns-Krull | first5=Christopher | last6=Latham | first6=David W. | last7=Shporer | first7=Avi | last8=Mazeh | first8=Tsevi | last9=Garcia-Melendo | first9=Enrique | display-authors=1 | journal=The Astrophysical Journal | date=2008 | volume=683 | issue=2 | pages=1076–1084 | arxiv=0804.4475 | bibcode=2008ApJ...683.1076W | doi=10.1086/589737 | s2cid=119266744 }}</ref>

<ref name="Winn2009">{{cite journal | title=On the Spin-Orbit Misalignment of the XO-3 Exoplanetary System | last1=Winn | first1=Joshua N. | last2=Johnson | first2=John Asher | last3=Fabrycky | first3=Daniel | last4=Howard | first4=Andrew W. | last5=Marcy | first5=Geoffrey W. | last6=Narita | first6=Norio | last7=Crossfield | first7=Ian J. | last8=Suto | first8=Yasushi | last9=Turner | first9=Edwin L. | display-authors=1 | journal=The Astrophysical Journal | date=2009 | volume=700 | issue=1 | pages=302–308 | arxiv=0902.3461 | bibcode=2009ApJ...700..302W | bibcode-access=free | doi=10.1088/0004-637X/700/1/302 | s2cid=2358804 }}</ref>

}}

==External links==
{{commons category-inline|XO-3 b|XO-3b}}
*{Norwegian} [http://forskning.no/romfart-romforskning-stub/2008/02/kjempeplanet-i-farta Kjempeplanet i farta] - forskning.no 1.6.07

{{Sky|04|21|53|+|57|49|01|850}}{{Camelopardalis}}

{{DEFAULTSORT:Xo-3b}}
[[Category:Camelopardalis]]
[[Category:Hot Jupiters]]
[[Category:Transiting exoplanets]]
[[Category:Giant planets]]
[[Category:Exoplanets discovered in 2007]]