Beta Pictoris b: Difference between revisions

| image = Artist’sBetapic impressionorbit ofv2 the planet Beta Pictoris breduced.jpggif

| caption = Artist'sThe impressionmotion of Beta Pictoris b. The debrisorbital diskplane aroundis viewed side-on; the parentplanet staris cannot bemoving seentowards the star.

| semimajor = 9.2 {{±val|10.018|0.4082|10.5}} [[astronomical unit076|ul=AU]]}}

| period eccentricity = 7890 ± 1000 [[day{{val|d]]<br>210.6 ± 2106|0.7 [[year007|y]]0.006}}

| inclinationperiod = 89.01 ± = {{val|23.593|0.36248|0.209|ul=yr}}

| mass = {{val|1211.9729|02.337|2.135}}<ref name="Chilcote2017"/><ref name="errors" group="noteFeng2022"/> {{Jupiter mass|link=y}}

| rotation rot_velocity = 8{{val|19.9|1 h.0|ul=km/s}}<ref name=eso "Landman2024"/>

| rotation = {{val|8.7|0.8|ul=h}}<ref name="Landman2024"/>
| single_temperature = {{nowrap|{{convert|1724|K|C F}}}}<br />{{nowrap|±{{convert|15|K-change|C-change F-change}}}}<ref name="Chilcote2017"/><ref name="errors" group="note"/>

'''Beta Pictoris b''' (abbreviated as '''β Pic b''') is an [[exoplanet]] orbiting the young [[debris disk]] [[A-type main sequence star]] [[Beta Pictoris]] located approximately 63 [[light-year]]s (19.4 [[parsec]]s, or nearly {{val|5.9862146|e=14}} [[km]]) away from [[Earth]] in the [[constellation]] of [[Pictor]]. It has a mass around 13 [[Jupiter mass]]es and a radius around 46% larger than [[Jupiter]]'s. It orbits at 9 [[Astronomical unit|AU]] from Beta Pictoris, which is about 3.5 times farther than the orbit of [[Beta Pictoris c]].<ref name="Nature">{{cite journal |last1=Lagrange |first1=A.-M. |last2=Meunier |first2=Pascal Rubini |last3=Keppler |first3=Miriam |last4=Galland |first4=Franck |author5=<em>et al.</em> |title=Evidence for an additional planet in the β Pictoris system |url=https://www.nature.com/articles/s41550-019-0857-1 |journal=Nature Astronomy |date=19 August 2019 |volume=3 |issue=12 |pages=1135–1142 |accessdate=20 August 2019 |doi=10.1038/s41550-019-0857-1|bibcode=2019NatAs...3.1135L |s2cid=202126059 }}</ref> It orbits (close to the plane of the debris disk orbiting the star), with a low eccentricity and a period of 20–21 years.

Beta Pictoris b is a [[super-Jupiter]], an exoplanet that has a radius and mass greater than that of the planet [[Jupiter]]. It has a temperature of {{convert|1724|K|C F}}, most likely due to its dusty atmosphere and mass (normally it would be much colder). It has a mass of between 9 and 13 [[Jupiter mass]]es ({{Jupiter mass}}),<ref name="Snellen">{{Cite journal | doi=10.1038/s41550-018-0561-6| title=The mass of the young planet Beta Pictoris b through the astrometric motion of its host star| journal=Nature Astronomy| volume=2| issue=11| pages=883–886| year=2018| last1=Snellen| first1=I. A. G.| last2=Brown| first2=A. G. A.|bibcode = 2018NatAs...2..883S|arxiv = 1808.06257| s2cid=118896628}}</ref>, and a radius of 1.46 {{Jupiter radius|link=y}}.<ref name="Chilcote2017"/> In 2018, a study directly measured the [[Methods of detecting exoplanets#Astrometry|astrometric perturbation]] of Beta Pictoris by Beta Pictoris b, one of the first examples of an exoplanet being measured directly by its astrometric perturbation. Its mass was directly measured as {{val|11|2}} {{Jupiter mass}}.<ref name="Snellen" />

The planet orbits an ([[Stellar classification#Class A|A-type]]) [[star]] named [[Beta Pictoris]]. The star has a mass of 1.75 [[solar mass]]es ({{Solar mass}}) and a radius of 1.8 [[solar radii]] ({{Solar radius}}). It has a surface temperature of 8056 [[Kelvin|K]] and is 12 million years old. In comparison, the Sun is about 4.6 billion years old<ref>{{cite web |url=http://www.universetoday.com/18237/how-old-is-the-sun/ |title=How Old is the Sun? |author=Fraser Cain |date=16 September 2008 |publisher=[[Universe Today]] |accessdateaccess-date=19 February 2011}}</ref> and has a surface temperature of 5778 K.<ref>{{cite web |url=http://www.universetoday.com/18092/temperature-of-the-sun/ |title=Temperature of the Sun |author=Fraser Cain |date=15 September 2008 |publisher=Universe Today |accessdateaccess-date=19 February 2011}}</ref> It is slightly metal-rich, with a [[metallicity]] ([Fe/H]) of 0.06, or 112% of that found in the Sun.<ref name="Gray2006">{{cite journal|bibcode=2006AJ....132..161G|title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc—The Southern Sample|author=Gray, R. O.|year=2006|journal=[[The Astronomical Journal]]|volume=132|issue=1|pages=161–170|doi=10.1086/504637|arxiv = astro-ph/0603770 |s2cid=119476992|display-authors=etal}}</ref> Its luminosity ({{solar luminosity|link=y}}) is 8.7 times that of the Sun.

Beta Pictoris b orbits its host star every 21 years at a distance of 9.2 [[astronomical unit|AU]] (about the same as [[Saturn]]'s distance, which is about 9.55 AU). It receives 11% of the amount of [[stellar flux|sunlight]] that Earth does from the Sun.<ref name="PHL">[http://www.hpcf.upr.edu/~abel/phl/hec_plots/hec_orbit/hec_orbit_beta_Pic_b.png Orbit Beta Picture]hpcf.upr.edu {{Webarchive|url=https://web.archive.org/web/20160828034017/https://www.hpcf.upr.edu/~abel/phl/hec_plots/hec_orbit/hec_orbit_beta_Pic_b.png |date=August 28, 2016 }}</ref>

The planet was discovered on November 18, 2008 by [[Anne-Marie Lagrange]] ''et al.'', using the NACO instrument on the [[Very Large Telescope]] at Cerro Paranal in northern [[Chile]].<ref name="LagrangeGratadour2009">{{cite journal |last1=Lagrange |first1=A.-M. |last2=Gratadour |first2=D. |last3=Chauvin |first3=G. |last4=Fusco |first4=T. |last5=Ehrenreich |first5=D. |last6=Mouillet |first6=D. |last7=Rousset |first7=G. |last8=Rouan |first8=D. |last9=Allard |first9=F. |last10=Gendron |first10=É. |last11=Charton |first11=J. |last12=Mugnier |first12=L. |last13=Rabou |first13=P. |last14=Montri |first14=J. |last15=Lacombe |first15=F. |title=A probable giant planet imaged in the β Pictoris disk |journal=Astronomy and Astrophysics |volume=493 |issue=2 |year=2009 |pages=L21–L25 |issn=0004-6361 |doi=10.1051/0004-6361:200811325|arxiv = 0811.3583 |bibcode = 2009A&A...493L..21L |s2cid=16548235 }}</ref> This planet was discovered using the [[Methods of detecting exoplanets#Direct imaging|direct imaging]] technique, using reference star differential imaging. The discovery image was taken in 2003, but the planet was not detected when the data were first reduced. A re-reduction of the data in 2008 using modern image processing tools revealed the faint [[point source]] now known to be a planet.

Follow-up observations performed in late 2009 and early 2010 using the same instrument recovered and confirmed the planet, but on the opposite side of the star. These findings were published in the journal ''[[Science (journal)|Science]]''<ref name="LagrangeBonnefoy2010">{{cite journal |last1=Lagrange |first1=A.- M. |last2=Bonnefoy |first2=M. |last3=Chauvin |first3=G. |last4=Apai |first4=D. |last5=Ehrenreich |first5=D. |last6=Boccaletti |first6=A. |last7=Gratadour |first7=D. |last8=Rouan |first8=D. |last9=Mouillet |first9=D. |last10=Lacour |first10=S. |last11=Kasper |first11=M. |title=A Giant Planet Imaged in the Disk of the Young Star Pictoris |journal=Science |volume=329 |issue=5987 |year=2010 |pages=57–59 |issn=0036-8075 |doi=10.1126/science.1187187|arxiv = 1006.3314 |bibcode = 2010Sci...329...57L |pmid=20538914|s2cid=5427102 }}</ref> and represented the closest orbiting planet to its star ever imaged. Observations performed in late 2010 and early 2011 allowed scientists to establish an [[Orbital inclination|inclination]] angle of the planet's orbit of 88.5 degrees, nearly edge-on. The location of the planet was found to be approximately 3.5 to 4 degrees tilted from the main disk in this system, indicating that the planet is aligned with the warped inner disk in the Beta Pictoris system.<ref name="ChauvinLagrange2012">{{cite journal|last1=Chauvin|first1=G.|last2=Lagrange|first2=A.-M.|last3=Beust|first3=H.|last4=Bonnefoy|first4=M.|last5=Boccaletti|first5=A.|last6=Apai|first6=D.|last7=Allard|first7=F.|last8=Ehrenreich|first8=D.|last9=Girard|first9=J. H. V.|last10=Mouillet|first10=D.|last11=Rouan|first11=D.|title=Orbital characterization of the β Pictoris b giant planet|journal=Astronomy & Astrophysics|volume=542|year=2012|pages=A41|issn=0004-6361|doi=10.1051/0004-6361/201118346|arxiv = 1202.2655 |bibcode = 2012A&A...542A..41C |s2cid=62806093}}</ref>

The first study of the spectral energy distribution of the planet was published in July 2013.<ref name="BonnefoyBoccaletti2013">{{cite journal |last1=Bonnefoy |first1=M. |last2=Boccaletti |first2=A. |last3=Lagrange |first3=A.-M. |last4=Allard |first4=F. |last5=Mordasini |first5=C. |last6=Beust |first6=H. |last7=Chauvin |first7=G. |last8=Girard |first8=J. H. V. |last9=Homeier |first9=D. |last10=Apai |first10=D. |last11=Lacour |first11=S. |last12=Rouan |first12=D. |title=The near-infrared spectral energy distribution ofβPictoris b |journal=Astronomy & Astrophysics |volume=555 |year=2013 |pages=A107 |issn=0004-6361 |doi=10.1051/0004-6361/201220838|arxiv = 1302.1160 |bibcode = 2013A&A...555A.107B |s2cid=54014134 }}</ref> This study shows detections at 1.265, 1.66, 2.18, 3.80, 4.05 and 4.78&nbsp;[[Micrometre|µmμm]] demonstrating that the planet has a very dusty and/or cloudy atmosphere. The SED is consistent with that of an early [[Brown dwarf#Spectral class L|L dwarf]], but with a lower surface gravity. The effective temperature is constrained to {{val|1700|100|ul=K}} and the surface gravity to log g = {{val|4.0|0.5}}. A second study, published in September 2013,<ref name="Currie2013"/> provided a new detection at 3.1&nbsp;µmμm obtained at the [[Gemini Observatory]] along with a reanalysis of previous data. They found the planet to be overluminous in the [[Infrared#Regions within the infrared|mid-infrared]] 3.1&nbsp;µmμm band compared to models of early L dwarfs. Models incorporating small dust particles and thick clouds provided the best fit to the SED. The effective temperature is constrained to {{val|1600|50|25|u=K}} and the surface gravity to log g = {{val|3.8|0.02}}. This fit corresponds to a planet radius of 1.65 times that of Jupiter, arguing that Beta Pictoris b may be younger than its host star (finished forming at 5&nbsp;Ma).

In 2015, a short video was made from direct images of Beta Pictoris b taken by the [[Gemini Planet Imager]] over the course of about two years showing a time-lapse of the planet orbiting around its parent star.<ref>{{Cite web|title = Watching an exoplanet in motion around a distant star {{!}} Astronomy Now|url = http://astronomynow.com/2015/09/17/watching-an-exoplanet-in-motion-around-a-distant-star/|accessdateaccess-date = 2015-09-29|first = Astronomy|last = Now}}</ref> It may have been responsible for a [[Planetary transit|transit]]-like event observed in 1981.

Stunning Exoplanet Time-lapse Beta Pictoris b.tif|Beta Pictoris b time-lapse.<ref>{{cite web |title=Stunning Exoplanet Time-lapse |url=https://www.eso.org/public/images/potw1846a/ |website=www.eso.org |accessdateaccess-date=12 November 2018}}</ref>

Beta Pictoris b instar Motionsystem.webmjpg|TheArtistic motionrendering of the Beta Pictoris b.system, Theshowing orbitalthe plane[[accretion isdisk]], viewed side-on;and the planettwo is not moving towards the starplanets.

* [[PicSatBeta Pictoris]]

{{reflistReflist|group="note"|refs=

{{reflistReflist|refs=

[[Category:Pictor (constellation)]]