{{Short description|Exoplanet}} {{Sky|13|50|06.28|-|40|50|08.89}} {{Infobox planet | extrasolarplanet = yes | name = HIP 67522 b | image = | image_size = | image_alt = | caption = | apsis = astron | discovery_ref = <ref name="17M"/> | discoverer = [[TESS Hunt for Young and Maturing Exoplanets|THYME]] (Rizzuto et al.) | discovery_site = | discovered = 2020 | discovery_method = [[Transit (astronomy)|Primary Transit]] | alt_names = [[Henry Draper Catalogue|HD]] 120411 b, [[Gaia (spacecraft)|Gaia DR2]] 6113920619134019456 b, [[Tycho Catalogue|TYC]] 7794-2268-1 b<ref>{{cite web|url=http://www.openexoplanetcatalogue.com/planet/HIP%2067522%20b/|title=HIP 67522|publisher=Open Exoplanet Catalogue|accessdate=January 25, 2022}}</ref> | orbit_ref = | periastron = | apoastron = | semimajor = | avg_speed = | eccentricity = {{val|0.059|0.193|0.046}}<ref name="HIP">{{cite encyclopedia|url=https://exoplanet.eu/catalog/hip_67522_b--7401/|title=Planet HIP 67522 b|date=1995 |encyclopedia=[[Extrasolar Planets Encyclopaedia]]|access-date=January 23, 2022}}</ref> | period = {{val|6.959503|0.000016}} [[day|d]]<ref name="HIP"/> | synodic_period = | inclination = {{val|89.34|0.45|0.54|u=deg}} (to plane of sky)<ref name="17M"/><br/>{{val|5.8|2.8|5.7}} [[degree (angle)|°]] (to host star's equator, projected)<ref name="17Mb">{{cite journal|last1=Heitzmann|first1=A.|last2=Zhou|first2=G.|last3=Quinn|first3=S. N.|last4=Marsden|first4=S. C.|last5=Wright|first5=D.|last6=Petit|first6=P.|last7=Vanderburg|first7=A. M.|last8=Bouma|first8=L. G.|last9=Mann|first9=A. W.|last10=Rizzuto|first10=A. C.|date=November 12, 2021|title=The Obliquity of HIP 67522 b: A 17 Myr Old Transiting Hot, Jupiter-sized Planet|journal=The Astrophysical Journal Letters|volume=922|issue=1|page=L1|arxiv=2109.04174|doi=10.3847/2041-8213/ac3485|bibcode=2021ApJ...922L...1H|s2cid=237452642 |doi-access=free }}</ref> | angular_dist = | long_periastron = | time_periastron = | arg_peri = {{val|343.0|92.0|140.0}} °<ref name="HIP"/> | semi-amplitude = | star = [[HIP 67522]] | physical_ref = | mean_radius = {{val|0.897|0.051}} {{Jupiter radius|link=y}}<ref name="HIP"/> | volume = | density = (''uncertain'')<ref name="Lavail2026"></ref> | mass = 13.8 ± 1.0, <20 {{Earth mass|sym=y|link=y}}<ref name="ab"/><ref name=thao/>, 29.8 ± 3 {{Earth mass|sym=y|link=y}}<ref name="Lavail2026"></ref> | surface_grav = | moment_of_inertia_factor = | escape_velocity = | albedo = | single_temperature = {{val|1174|21}} [[kelvin|K]]<ref name="HIP"/> }}
'''HIP 67522 b''' is a [[hot Neptune]] or [[sub-Saturn]] exoplanet orbiting the [[G-type main-sequence star|G-type star]]<ref name="NASA">{{cite web|url=https://exoplanets.nasa.gov/exoplanet-catalog/7659/hip-67522-b/|title=HIP 67522 b|date=24 July 2020 |publisher=exoplanets.nasa.gov|accessdate=January 23, 2022}}</ref> [[HIP 67522]], approximately 415 [[light-years]] from [[Earth]]<ref name="NASA"/> in the constellation [[Centaurus]].<ref name=thao>{{Cite journal |last1=Thao |first1=Pa Chia |last2=Mann |first2=Andrew W. |last3=Feinstein |first3=Adina D. |last4=Gao |first4=Peter |last5=Thorngren |first5=Daniel |last6=Rotman |first6=Yoav |last7=Welbanks |first7=Luis |last8=Brown |first8=Alexander |last9=Duvvuri |first9=Girish M. |last10=France |first10=Kevin |last11=Longo |first11=Isabella |last12=Sandoval |first12=Angeli |last13=Schneider |first13=P. Christian |last14=Wilson |first14=David J. |last15=Youngblood |first15=Allison |date=2024-12-01 |title=The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST |journal=The Astronomical Journal |volume=168 |issue=6 |pages=297 |arxiv=2409.16355 |bibcode=2024AJ....168..297T |doi=10.3847/1538-3881/ad81d7 |doi-access=free |issn=0004-6256}}</ref> It was discovered using the [[Transiting Exoplanet Survey Satellite]] (TESS). It is one of the youngest transiting planets of any type, and one of only four others less than 100 million years old (along with [[AU Microscopii b|AU Mic b]], [[V1298 Tauri|V1298 Tau c]], [[DS Tucanae|DS Tuc Ab]] and [[TOI-942|TOI-942 b]]) to have the angle between its orbit and its host star's rotation measured, at {{val|5.8|2.8|5.7}} degrees.<ref name="17Mb"/> This planet, in turn, may help in understanding how other hot Neptunes form.
There is also evidence that another planet might also be present in the planetary system.<ref name="17M"/>
== Characteristics and formation == Due to its young age, HIP 67522 b has not reached its final size. Also due to the [[Kelvin–Helmholtz mechanism]],<ref name="17Mb"/> which occurs as a result of the planet itself cooling, its internal pressure drops, which will in turn cause the planet to shrink. Its final size will depend on the composition of its [[planetary core|core]].<ref>{{cite journal|last1=Lopez|first1=E. D.|last2=Fortney|first2=J. J.|title=The Role of Core Mass in Controlling Evaporation: The Kepler Radius Distribution and the Kepler-36 Density Dichotomy|date=September 17, 2013|url=https://iopscience.iop.org/article/10.1088/0004-637X/776/1/2/meta|journal=The Astrophysical Journal|volume=776|issue=1|page=2|arxiv=1305.0269|doi=10.1088/0004-637X/776/1/2|bibcode=2013ApJ...776....2L|s2cid=118545757 }}</ref>
It was shown in 2024 that HIP 67522 b is one of the [[List of exoplanet extremes|least dense]] known planets, with a density less than 0.10 g/cm<sup>3</sup>. It might have formed beyond the water-[[frost line (astrophysics)|snowline]], where the contamination by both rocky and [[ice giant|icy]] materials frequently takes place.<ref name="ab">{{cite news|last=Cowing|first=Keith|title=The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST|url=https://astrobiology.com/2024/10/the-featherweight-giant-unraveling-the-atmosphere-of-a-17-myr-planet-with-jwst.html|website=Astrobiology|date=8 October 2024|accessdate=11 October 2024}}</ref><ref name=thao/> In 2025, it was revealed with certainty that HIP 67522 b triggers the increase in flare from the host star via the star-planet [[magnetism|magnetic]] interactions. These flares might have caused the shrinkage of the planet's atmosphere.<ref>{{Cite journal |last1=Ilin |first1=Ekaterina |last2=Vedantham |first2=Harish K. |last3=Poppenhäger |first3=Katja |last4=Bloot |first4=Sanne |last5=Callingham |first5=Joseph R. |last6=Brandeker |first6=Alexis |last7=Chakraborty |first7=Hritam |date=2025-07-02 |title=Close-in planet induces flares on its host star |url=https://www.nature.com/articles/s41586-025-09236-z |journal=Nature |volume=643 |issue=8072 |language=en |pages=645–648 |doi=10.1038/s41586-025-09236-z |pmid=40604272 |arxiv=2507.00791 |bibcode=2025Natur.643..645I |issn=1476-4687 |url-access=subscription }}</ref> In 2026, by using [[Very Large Telescope|VLT]], the presence of [[water vapour]] (H<sub>2</sub>O) and [[carbon monoxide]] (CO) in the planet's atmosphere was revealed with high confidence, along with day-to-night [[wind]]s. The mass of planet was measured at 29.8 ± 3 {{Earth mass|link=y}}, which is 3σ inconsistent with the previous estimate from [[James Webb Space Telescope|JWST]]. Also a tentative detection of [[semiheavy water]] (HDO) was reported, which would be the first detection of [[deuterium]] in exoplanet's atmosphere if confirmed.<ref name="Lavail2026">{{cite arXiv |last1=Lavail |first1=A. |last2=Debras |first2=F. |last3=Klein |first3=B. |last4=Chabrol |first4=E. |last5=Vinatier |first5=S. |last6=Hood |first6=T. |last7=Masson |first7=A. |last8=Seidel |first8=J. V. |last9=Moutou |first9=C. |last10=Aigrain |first10=S. |last11=Meech |first11=A. |last12=Barragán |first12=O. |eprint=2602.03498 |title=Atmospheric characterization of HIP 67522 b with VLT/CRIRES+. VLT/CRIRES+ suggests a heavier planet and hints at deuterium fractionation |date=2026 |class=astro-ph.EP }}</ref>
==References== <references> <ref name="17M">{{cite journal|last1=Rizzuto|first1=A. C.|last2=Newton|first2=E. R.|last3=Mann|first3=A. W.|last4=Tofflemire|first4=B. M.|last5=Vanderburg|first5=A.|last6=Kraus|first6=A. L.|last7=Wood|first7=M. L.|last8=Quinn|first8=S. N.|last9=Zhou|first9=G.|last10=Thao|first10=P. C.|last11=Law|first11=N. M.|last12=Ziegler|first12=C.|last13=Briceño|first13=César|date=June 22, 2020|title=TESS Hunt for Young and Maturing Exoplanets (THYME). II. A 17 Myr Old Transiting Hot Jupiter in the Sco-Cen Association|journal=The Astronomical Journal|volume=160|issue=1|page=33|arxiv=2005.00013|doi=10.3847/1538-3881/ab94b7|bibcode=2020AJ....160...33R|s2cid=218470215 |doi-access=free }}</ref> </references>
{{Centaurus}}
[[Category:Exoplanets discovered in 2020]] [[Category:Exoplanets discovered by TESS]] [[Category:Hot Jupiters]] [[Category:Transiting exoplanets]]