From Wikipedia, the free encyclopedia
HD 63433 c
Discovery
Discovered byMann et al. ( THYME) [1]
Discovery date30 April 2020 [1]
Transit [2]
Designations
TOI-1726 c, BD+27 1490 c, HIP 38228 c, V377 Geminorum c
Orbital characteristics [1]
0.1448+0.0073
−0.0077  AU
Eccentricity0.21+0.33
−0.14
20.54 days
Inclination89.28 °+0.4 °
−0.22 °
Star HD 63433
Physical characteristics [3]
Mean radius
2.692±0.108  R🜨
Mass15.54±3.86  M🜨
Mean density
4.6±1.3  g/cm3
Temperature Teq: 540+10
−9 [a] — 679+13
−11 K [b]

HD 63433 c (TOI-1726 c) is a mini-Neptune exoplanet orbiting the Sun-like star HD 63433. [4] It is the outermost planet in its planetary system, being located 0.1448 astronomical units (21,660,000 km) from its star, and completing one orbit every 21 days. [1] Despite being the outermost planet in the system, it is still located close to its star, meaning that its temperature is hot, being estimated between 267 and 406 °C. [3] HD 63433 c is about 2.7 times larger than Earth and 15.5 times more massive, [3] but still smaller and less massive than Neptune. [note 1] In 2022, a study showed that its atmosphere, made up of hydrogen, is being evaporated by the strong radiation from its star, causing it to slowly turn into a super-Earth planet. [6] [7]

Characteristics

HD 63433 c is classified as a mini-Neptune planet, [6] a class of planets that are smaller than Neptune but still have an atmosphere of hydrogen and/or helium, just like Neptune. [6] According to theoretical models, its composition is mainly of silicate and water, surrounded by a gaseous envelope that makes up about 2% of the planet. [3] HD 63433 c is 2.7 times larger than Earth, but still 1/3 smaller than the Solar System's ice giants, Neptune and Uranus. [3] [note 2] Its mass is about 15.5 ME, being situated between the masses of Uranus and Neptune, which are 14.54 and 17.15 ME respectively. [5] [8] The density of HD 63433 c is calculated at 4.6 g/cm3, [3] slightly lower than Earth's, [note 3] but higher than the densities of Neptune and Uranus. [note 4] The age of the planet is estimated at 400 million years. [4]

It is the outermost planet in its planetary system, orbiting its star at a distance of 0.145 astronomical units (21,700,000 km), with an orbital period of 21 days. [1] Despite being the outermost planet, its distance is about 37% of Mercury's distance from the Sun, [c] in addition to having a high temperature, estimated between 267 and 406 degrees Celsius. [3] [d]

Size comparison
Neptune HD 63433 c
Neptune Exoplanet

The discovery of HD 63433 c, as well as all planets orbiting HD 63433, is part of a project called TESS Hunt for Young and Maturing Exoplanets (THYME), whose objective is to discover transiting exoplanets in stellar associations, moving groups and open clusters. [4] [1] It was discovered in 2020 by Mann et al., using the Transiting Exoplanet Survey Satellite (TESS), together with HD 63433 b. [11] Both planets were discovered through the transit method. [11]

Evaporating atmosphere

In 2022, a study led by Michael Zhang observed two mini-Neptunes from distinct planetary systems: HD 63433 c, using the Hubble Space Telescope, and TOI-560.01, using the W. M. Keck Observatory. [7] This study revealed that the atmospheres of the two planets – made up mainly of hydrogen (HD 63433 c) and helium (TOI-560.01) – are evaporating and transforming them into super-Earths, as the strong radiation of their host stars is slowly stripping away their puffy atmospheres, causing them to escape into space, like a hot air balloon. [7] [2] In HD 63433 c in particular, these gases are escaping at a speed of 50 km/s, and forming a gas cocoon 12 times larger than the planet itself. [7]

The same effect was not identified on the sibling planet HD 63433 b, which could indicate that it has already lost its primordial atmosphere. [7]

Host star

Main article: HD 63433

The host star of HD 63433 c is HD 63433, a G-type main-sequence star that is located 73 light-years from Earth in the constellation Gemini. [4] [note 5] The properties of this star, such as its radius (0.912 R☉) and its mass (0.99 M☉) are very similar to those of the Sun, which makes it classified as a Solar analog. [4] The star is part of the Ursa Major moving group, allowing its age to be estimated at 414±23 million years. [4] There are other exoplanets orbiting this star, HD 63433 b, also a mini-Neptune, and HD 63433 d, an Earth-sized planet. [1]

See also

Notes and references

  1. ^ a b c d e f g Capistrant, Benjamin K.; Soares-Furtado, Melinda; Vanderburg, Andrew; Jankowski, Alyssa; Mann, Andrew W.; Ross, Gabrielle; Srdoc, Gregor; Hinkel, Natalie R.; Becker, Juliette (2024-01-09), "TESS Hunt for Young and Maturing Exoplanets (THYME) XI: An Earth-sized Planet Orbiting a Nearby, Solar-like Host in the 400Myr Ursa Major Moving Group", The Astronomical Journal, 167 (2): 54, arXiv: 2401.04785, Bibcode: 2024AJ....167...54C, doi: 10.3847/1538-3881/ad1039
  2. ^ a b "Puffy Planets Lose Atmospheres, Become Super-Earths". hubblesite.org. February 3, 2022. Retrieved January 11, 2023.
  3. ^ a b c d e f g Mallorquín, M.; Béjar, V. J. S.; Lodieu, N.; Osorio, M. R. Zapatero; Tabernero, H.; Mascareño, A. Suárez; Zechmeister, M.; Luque, R.; Pallé, E.; Montes, D. (2023-03-01). "Dynamical masses of two young transiting sub-Neptunes orbiting HD 63433". Astronomy & Astrophysics. 671: A163. arXiv: 2303.15411. Bibcode: 2023A&A...671A.163M. doi: 10.1051/0004-6361/202245397. ISSN  0004-6361.
  4. ^ a b c d e f Mann, Andrew W.; Johnson, Marshall C.; Vanderburg, Andrew; Kraus, Adam L.; Rizzuto, Aaron C.; Wood, Mackenna L.; Bush, Jonathan L.; Rockcliffe, Keighley; Newton, Elisabeth R.; Latham, David W.; Mamajek, Eric E.; Zhou, George; Quinn, Samuel N.; Thao, Pa Chia; Benatti, Serena (2020-10-01). "TESS Hunt for Young and Maturing Exoplanets (THYME). III. A Two-planet System in the 400 Myr Ursa Major Group". The Astronomical Journal. 160 (4): 179. arXiv: 2005.00047. Bibcode: 2020AJ....160..179M. doi: 10.3847/1538-3881/abae64. ISSN  0004-6256.
  5. ^ a b c d "Neptune Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved January 18, 2024.
  6. ^ a b c Zhang, Michael; Knutson, Heather A.; Wang, Lile; Dai, Fei; Santos, Leonardo A. dos; Fossati, Luca; Henry, Gregory W.; Ehrenreich, David; Alibert, Yann; Hoyer, Sergio; Wilson, Thomas G.; Bonfanti, Andrea (2022-02-01). "Detection of Ongoing Mass Loss from HD 63433c, a Young Mini Neptune". The Astronomical Journal. 163 (2): 68. arXiv: 2106.05273. Bibcode: 2022AJ....163...68Z. doi: 10.3847/1538-3881/ac3f3b. ISSN  0004-6256.
  7. ^ a b c d e "Puffy planets lose atmospheres, become super-Earths". phys.org. Retrieved 2024-01-11.
  8. ^ a b c "Uranus Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved January 18, 2024.
  9. ^ "Facts About Earth - NASA Science". science.nasa.gov. Retrieved 2023-12-04.
  10. ^ "Mercury Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved January 18, 2023.
  11. ^ a b "HD 63433". Open Exoplanet Catalogue. Archived from the original on January 14, 2024. Retrieved January 14, 2024.
  12. ^ "HD 63433". simbad.cds.unistra.fr. Retrieved 2024-01-11.
  1. ^ Assuming an albedo of 0.6
  2. ^ Assuming an albedo of 0
  3. ^ The distance of Mercury to the Sun is 0.387 AU. [10]
  4. ^ Assuming albedos of 0.6 and 0 respectively.
  1. ^ Neptune is 3.883 times larger than Earth, and 17.15 times more massive. [5]
  2. ^ The radius of Neptune and Uranus are 3.883 R🜨 [5] and 4.007 R🜨 [8] respectively.
  3. ^ The density of Earth is 5.513 g/cm3. [9]
  4. ^ The densities of Neptune and Uranus are 1.638 g/cm3 [5] and 1.27 g/cm3 [8] respectively.
  5. ^ Obtained with a right ascension of 07h 49m 55.06s and a declination of 27° 21′ 47.5″ [12] on this website.
Retrieved from " https://en.wikipedia.org/?title=HD_63433_c&oldid=1200581543"