HIP 67522 b is a hot Jupiter exoplanet orbiting the G-type star[6] HIP 67522, located approximately 415 light-years from Earth[6] in the constellation Centaurus, discovered using the Transiting Exoplanet Survey Satellite (TESS). It is currently the youngest hot Jupiter discovered, at an age of only 17 million years;[1] 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 5.8+2.8
−5.7
degrees.[4] This planet, in turn, may help in knowing how other hot Jupiters form.

HIP 67522 b
Discovery[1]
Discovered byTHYME (Rizzuto et al.)
Discovery date2020
Primary Transit
Designations
HD 120411 b, Gaia DR2 6113920619134019456 b, TYC 7794-2268-1 b[2]
Orbital characteristics
Eccentricity0.059+0.193
−0.046
[3]
6.959503±0.000016 d[3]
Inclination89.34°+0.45°
−0.54°
(to plane of sky)[1]
5.8+2.8
−5.7
° (to host star's equator, projected)[4]
343.0+92.0
−140.0
°[3]
StarHIP 67522
Physical characteristics
0.8984±0.0419 RJ[3]
Mass<20 ME[5]
Mean density
<0.10 g/cm3[5]
Temperature1174±21 K[3]

Due to its young age, it has not reached its final size. Also due to the Kelvin–Helmholtz mechanism,[4] 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.[7]

There is also evidence that another planet might also be present in the planetary system.[1]

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.[5]

References

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  1. ^ a b c d Rizzuto, A. C.; Newton, E. R.; Mann, A. W.; Tofflemire, B. M.; Vanderburg, A.; Kraus, A. L.; Wood, M. L.; Quinn, S. N.; Zhou, G.; Thao, P. C.; Law, N. M.; Ziegler, C.; Briceño, César (June 22, 2020). "TESS Hunt for Young and Maturing Exoplanets (THYME). II. A 17 Myr Old Transiting Hot Jupiter in the Sco-Cen Association". The Astronomical Journal. 160 (1): 33. arXiv:2005.00013. Bibcode:2020AJ....160...33R. doi:10.3847/1538-3881/ab94b7. S2CID 218470215.
  2. ^ "HIP 67522". Open Exoplanet Catalogue. Retrieved January 25, 2022.
  3. ^ a b c d e "Planet HIP 67522 b". Extrasolar Planets Encyclopaedia. 1995. Retrieved January 23, 2022.
  4. ^ a b c Heitzmann, A.; Zhou, G.; Quinn, S. N.; Marsden, S. C.; Wright, D.; Petit, P.; Vanderburg, A. M.; Bouma, L. G.; Mann, A. W.; Rizzuto, A. C. (November 12, 2021). "The Obliquity of HIP 67522 b: A 17 Myr Old Transiting Hot, Jupiter-sized Planet". The Astrophysical Journal Letters. 922 (1): L1. arXiv:2109.04174. Bibcode:2021ApJ...922L...1H. doi:10.3847/2041-8213/ac3485. S2CID 237452642.
  5. ^ a b c Cowing, Keith (8 October 2024). "The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST". Astrobiology. Retrieved 11 October 2024.
  6. ^ a b "HIP 67522 b". exoplanets.nasa.gov. Retrieved January 23, 2022.
  7. ^ Lopez, E. D.; Fortney, J. J. (September 17, 2013). "The Role of Core Mass in Controlling Evaporation: The Kepler Radius Distribution and the Kepler-36 Density Dichotomy". The Astrophysical Journal. 776 (1): 2. arXiv:1305.0269. Bibcode:2013ApJ...776....2L. doi:10.1088/0004-637X/776/1/2. S2CID 118545757.