HIP 67522 b

{{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 =

| discoverer = THYME (Rizzuto et al.)

| discovery_site =

| discovered = 2020

| discovery_method = Primary Transit

| alt_names = HD 120411 b, Gaia DR2 6113920619134019456 b, TYC 7794-2268-1 b{{cite web|url=http://www.openexoplanetcatalogue.com/planet/HIP%2067522%20b/|title=HIP 67522|publisher=Open Exoplanet Catalogue|accessdate=January 25, 2022}}

| orbit_ref =

| periastron =

| apoastron =

| semimajor =

| avg_speed =

| eccentricity = {{val|0.059|0.193|0.046}}{{cite web|url=https://exoplanet.eu/catalog/hip_67522_b--7401/|title=Planet HIP 67522 b|date=1995 |work=Extrasolar Planets Encyclopaedia|access-date=January 23, 2022}}

| period = {{val|6.959503|0.000016}} d

| synodic_period =

| inclination = {{val|89.34|0.45|0.54|u=deg}} (to plane of sky)
{{val|5.8|2.8|5.7}} ° (to host star's equator, projected){{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 }}

| angular_dist =

| long_periastron =

| time_periastron =

| arg_peri = {{val|343.0|92.0|140.0}} °

| semi-amplitude =

| star = HIP 67522

| physical_ref =

| mean_radius = {{val|0.8984|0.0419}} {{Jupiter radius|link=y}}

| volume =

| density = {{val|0.10|p=<|ul=g/cm3}}

| mass = <20 {{Earth mass|link=y}}

| surface_grav =

| moment_of_inertia_factor =

| escape_velocity =

| albedo =

| single_temperature = {{val|1174|21}} K

}}

HIP 67522 b is a hot Jupiter exoplanet orbiting the G-type star{{cite web|url=https://exoplanets.nasa.gov/exoplanet-catalog/7659/hip-67522-b/|title=HIP 67522 b|publisher=exoplanets.nasa.gov|accessdate=January 23, 2022}} HIP 67522, approximately 415 light-years from Earth in the constellation Centaurus. It was discovered using the Transiting Exoplanet Survey Satellite (TESS). It is currently the youngest planet of its kind known to astronomers, with an age of only 17 million years; it is also one of the youngest transiting planets of any type, and one of only four others less than 100 million years old (along with AU Mic b, V1298 Tau c, DS Tuc Ab and 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. This planet, in turn, may help in knowing how other hot Jupiters form.

Due to its young age, it has not reached its final size. Also due to the Kelvin–Helmholtz mechanism, 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 core.{{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}}

There is also evidence that another planet might also be present in the planetary system.

It was shown in 2024 that HIP 67522 b is one of the least dense known planets, with a density less than 0.10 g/cm³. It might have formed beyond the water-snowline, where the contamination by rocky and icy materials usually takes place.{{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}}