Blanet
{{Short description|Hypothetical planet that orbits a black hole}}
A blanet is a member of a hypothetical class of exoplanets that directly orbit black holes.{{Cite web|last= Letzter|first=R.|date= 6 August 2020|title= Thousands of Earthlike 'blanets' might circle the Milky Way's central black hole|url=https://www.space.com/black-hole-planets-blanets.html|access-date=2020-08-08|website=Space.com}}
Blanets are fundamentally similar to other planets; they have enough mass to be rounded by their own gravity, but are not massive enough to start thermonuclear fusion and become stars. In 2019, a team of astronomers and exoplanetologists showed that there is a safe zone around a supermassive black hole that could harbor thousands of blanets in orbit around it.{{cite journal|last1=Wada|first1= K.|last2= Tsukamoto|first2= Y.|last3= Kokubo|first3= E.|title=Planet Formation around Supermassive Black Holes in the Active Galactic Nuclei |journal=The Astrophysical Journal|volume= 886|issue= 2|date= 26 November 2019|pages= 107|doi= 10.3847/1538-4357/ab4cf0|arxiv= 1909.06748|bibcode= 2019ApJ...886..107W|doi-access= free}}{{cite journal |last1= Wada|first1= K.|last2= Tsukamoto|first2= Y.|last3= Kokubo|first3= E.|title= Formation of "Blanets" from Dust Grains around the Supermassive Black Holes in Galaxies|journal= The Astrophysical Journal|year= 2021|volume= 909|issue= 1|page= 96|doi= 10.3847/1538-4357/abd40a|arxiv=2007.15198|bibcode= 2021ApJ...909...96W|s2cid= 220870610|doi-access= free}}
Etymology
The team led by Keiichi Wada of Kagoshima University in Japan has given this name to black hole planets.{{Cite web|last= Starr|first=M.|title=We Have Ploonets. We Have Moonmoons. Now Hold Onto Your Hats For... Blanets|date= 3 August 2020|url= https://www.sciencealert.com/we-have-ploonets-we-have-moonmoons-now-hold-onto-your-hats-for-blanets|access-date= 2020-08-08|website= ScienceAlert}} The word is a portmanteau of black hole and planet.
Formation
Blanets are suspected to form in the accretion disk that orbits a sufficiently large black hole.{{Cite web|last= Greene|first=T.|date= 2020-08-04|title= Scientists: What if black holes had a safe zone where little planets could live? Let's call them 'blanets'|url= https://thenextweb.com/insider/2020/08/04/scientists-what-if-black-holes-had-a-safe-zone-where-little-planets-could-live-lets-call-them-blanets/|access-date= 2020-08-08|website=The Next Web}}
Possible candidates
- The unconfirmed extragalactic planet M51-ULS-1b.{{Cite web |title=Chandra Sees Evidence for Possible Planet in Another Galaxy - NASA |url=https://www.nasa.gov/image-article/chandra-sees-evidence-possible-planet-another-galaxy/ |access-date=2024-08-07 |language=en-US}}
- The unconfirmed planet or brown dwarf, IGR J12580+0134 b, being disrupted by a supermassive black hole.{{Cite web |last=Martin |first=Pierre-Yves |date=2016 |title=Planet IGR J12580+0134 b |url=https://exoplanet.eu/catalog/igr_j12580_0134_b--9454/ |access-date=2024-11-03 |website=exoplanet.eu |language=en}}{{Cite journal |last1=Lei |first1=Wei-Hua |last2=Yuan |first2=Qiang |last3=Zhang |first3=Bing |last4=Wang |first4=Daniel |date=2016-01-01 |title=Igr J12580+0134: The First Tidal Disruption Event with an Off-Beam Relativistic Jet |journal=The Astrophysical Journal |volume=816 |issue=1 |pages=20 |doi=10.3847/0004-637X/816/1/20 |doi-access=free |issn=0004-637X|arxiv=1511.01206 }}
In fiction
- In the two episodes "The Impossible Planet" and "The Satan Pit" (both 2006) of the British television series Doctor Who, the plot of the episode takes place on the titular “impossible planet”, a barren blanet called Krop Tor orbiting a black hole called K37 Gem 5.
- In Interstellar (2014), two of the 3 terrestrial planets orbiting supermassive black hole Gargantua are proper blanets. The other one orbits a main-sequence star named Pantagruel.
References
{{Spoken Wikipedia|date=2025-01-25|English Narration of Blanet.mp3}}
{{Exoplanet}}