Blanet

Last updated

A blanet is a member of a hypothetical class of exoplanets that directly orbit black holes. [1]

Contents

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. [2] [3]

Etymology

The team led by Keiichi Wada of Kagoshima University in Japan has given this name to black hole planets. [4] 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. [3] [5]

Possible candidates

In fiction

Related Research Articles

<span class="mw-page-title-main">Sagittarius A*</span> Supermassive black hole at the center of the Milky Way

Sagittarius A*, abbreviated as Sgr A*, is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, visually close to the Butterfly Cluster (M6) and Lambda Scorpii.

HD 20782 is the primary of a wide binary system located in the southern constellation Fornax. It has an apparent magnitude of 7.38, making it readily visible in binoculars but not to the naked eye. The system is located relatively close at a distance of 117 light-years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of 40.7 km/s. At its current distance, HD 20782's brightness is diminished by 0.12 magnitudes due to interstellar extinction and it has an absolute magnitude of +4.61.

<span class="mw-page-title-main">55 Cancri e</span> Hot Super-Earth orbiting 55 Cancri A

55 Cancri e is an exoplanet orbiting a Sun-like host star, 55 Cancri A. The mass of the exoplanet is about eight Earth masses and its diameter is about twice that of the Earth. 55 Cancri e was discovered on 30 August 2004, thus making it the first super-Earth discovered around a main sequence star, predating Gliese 876 d by a year. It is the innermost planet in its planetary system, taking less than 18 hours to complete an orbit. However, until the 2010 observations and recalculations, this planet had been thought to take about 2.8 days to orbit the star.

An extragalactic planet, also known as an extragalactic exoplanet or an extroplanet, is a star-bound planet or rogue planet located outside of the Milky Way Galaxy. Due to the immense distances to such worlds, they would be very hard to detect directly. However, indirect evidence suggests that such planets exist. Nonetheless, the most distant known planets are SWEEPS-11 and SWEEPS-04, located in Sagittarius, approximately 27,710 light-years from the Sun, while the Milky Way is about 87,400 light-years in diameter. This means that even galactic planets located further than that distance have not been detected.

<span class="mw-page-title-main">NGC 4845</span> Spiral galaxy in the constellation Virgo

NGC 4845 is a spiral galaxy located in the constellation Virgo around 65 million light years away. The galaxy was originally discovered by William Herschel in 1786. It is a member of the NGC 4753 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.

59 Virginis is a G-type main-sequence star, located in constellation Virgo at approximately 57 light-years from Earth.

Manuela Campanelli is a distinguished professor of astrophysics of the Rochester Institute of Technology. She also holds the John Vouros endowed professorship at RIT and is the director of its Center for Computational Relativity and Gravitation. Her work focuses on the astrophysics of merging black holes and neutron stars, which are powerful sources of gravitational waves, electromagnetic radiation and relativistic jets. This research is central to the fields of relativistic astrophysics and gravitational-wave astronomy.

<span class="mw-page-title-main">Disrupted planet</span> Planet or related being destroyed by a passing object

In astronomy, a disrupted planet is a planet or exoplanet or, perhaps on a somewhat smaller scale, a planetary-mass object, planetesimal, moon, exomoon or asteroid that has been disrupted or destroyed by a nearby or passing astronomical body or object such as a star. Necroplanetology is the related study of such a process.

<span class="mw-page-title-main">NGC 4660</span> Galaxy in the constellation Virgo

NGC 4660 is an elliptical galaxy located about 63 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer William Herschel on March 15, 1784 and is a member of the Virgo Cluster.

K2-32 is a G9-type main sequence star slightly smaller and less massive than the sun. Four confirmed transiting exoplanets are known to orbit this star. A study of atmospheric escape from the planet K2-32b caused by high-energy stellar irradiation indicates that the star has always been a very slow rotator.

Tau Ceti f is a potential super-Earth or mini-Neptune orbiting Tau Ceti that was discovered in 2012 by statistical analyses of the star's variations in radial velocity, based on data obtained using HIRES, AAPS, and HARPS. It is of interest because its orbit places it in Tau Ceti's extended habitable zone, but a 2015 study implies that there may not be a detectable biosignature because it has only been in the temperate zone for less than one billion years. In 2017, it was again recovered from radial-velocity data, along with Tau Ceti e. Despite this, it remains an unconfirmed candidate.

Kepler-167 is a K-type main-sequence star located about 1,119 light-years (343 pc) away from the Solar System in the constellation of Cygnus. The star has about 78% the mass and 75% the radius of the Sun, and a temperature of 4,884 K. It hosts a system of four known exoplanets. There is also a companion red dwarf star at a separation of about 700 AU, with an estimated orbital period of over 15,000 years.

TOI-1227 b is one of the youngest transiting exoplanets discovered, alongside K2-33b and HIP 67522 b. The exoplanet TOI-1227 b is about 11±2 million years old and currently 9.6 R🜨 large. It will become a 3-5 R🜨 planet in about 1 billion years, because the planet is still contracting. TOI-1227 b orbits its host star every 27.36 days.

<span class="mw-page-title-main">SDSS J0849+1114</span> Trio of interacting galaxies in the constellation Cancer

SDSS J0849+1114 is a late-stage galaxy merger forming from a trio of galaxies located in the constellation of Cancer. At the redshift of 0.077, they are located 1.06 billion light-years from Earth. First discovered as a triple active galactic nucleus (AGN) candidate in a Sloan Digital Sky Survey study published in 2011, they received significant attention when astronomers discovered it harbors three supermassive black holes in its center.

<span class="mw-page-title-main">Little red dot (galaxy)</span> Class of galaxies

Little red dots (LRDs) are a class of small, red-tinted galaxies discovered by the James Webb Space Telescope. Their discovery was published in March 2024, and they are currently poorly understood. They appear to have existed between 0.6 and 1.6 billion years after the Big Bang, from 13.2 to 12.2 billion years ago.

References

  1. Letzter, R. (6 August 2020). "Thousands of Earthlike 'blanets' might circle the Milky Way's central black hole". Space.com. Retrieved 2020-08-08.
  2. Wada, K.; Tsukamoto, Y.; Kokubo, E. (26 November 2019). "Planet Formation around Supermassive Black Holes in the Active Galactic Nuclei". The Astrophysical Journal. 886 (2): 107. arXiv: 1909.06748 . Bibcode:2019ApJ...886..107W. doi: 10.3847/1538-4357/ab4cf0 .
  3. 1 2 Wada, K.; Tsukamoto, Y.; Kokubo, E. (2021). "Formation of "Blanets" from Dust Grains around the Supermassive Black Holes in Galaxies". The Astrophysical Journal. 909 (1): 96. arXiv: 2007.15198 . Bibcode:2021ApJ...909...96W. doi: 10.3847/1538-4357/abd40a . S2CID   220870610.
  4. Starr, M. (3 August 2020). "We Have Ploonets. We Have Moonmoons. Now Hold Onto Your Hats For... Blanets". ScienceAlert. Retrieved 2020-08-08.
  5. Greene, T. (2020-08-04). "Scientists: What if black holes had a safe zone where little planets could live? Let's call them 'blanets'". The Next Web. Retrieved 2020-08-08.
  6. "Chandra Sees Evidence for Possible Planet in Another Galaxy - NASA" . Retrieved 2024-08-07.
  7. Martin, Pierre-Yves (2016). "Planet IGR J12580+0134 b". exoplanet.eu. Retrieved 2024-11-03.
  8. Lei, Wei-Hua; Yuan, Qiang; Zhang, Bing; Wang, Daniel (2016-01-01). "Igr J12580+0134: The First Tidal Disruption Event with an Off-Beam Relativistic Jet". The Astrophysical Journal. 816 (1): 20. arXiv: 1511.01206 . doi: 10.3847/0004-637X/816/1/20 . ISSN   0004-637X.