Quasi-star

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Size comparison of a hypothetical quasi-star to some of the largest known stars. Quasi-star size comparison.png
Size comparison of a hypothetical quasi-star to some of the largest known stars.
A quasi-star rendered with Celestia Quasi-star Celestia.png
A quasi-star rendered with Celestia

A quasi-star (also called black hole star) is a hypothetical type of extremely massive and luminous star that may have existed early in the history of the Universe. They are thought to live around 7-10 million years. Unlike modern stars, which are powered by nuclear fusion in their cores, a quasi-star's energy would come from material falling into a black hole at its core. Quasars emit massive amounts of energy across the electromagnetic spectrum, from radio waves to gamma rays. They were first identified in the 1960s and have since provided valuable insights into the early universe, galaxy formation, and the behavior of black holes. It is also known to be the largest stars in the universe. [1]

Contents

Formation and properties

A quasi-star would have resulted from the core of a large protostar collapsing into a black hole, where the outer layers of the protostar are massive enough to absorb the resulting burst of energy without being blown away or falling into the black hole, as occurs with modern supernovae. Such a star would have to be at least 1,000 solar masses (2.0×1033 kg). [2] Quasi-stars may have also formed from dark matter halos drawing in enormous amounts of gas via gravity, which can produce supermassive stars with tens of thousands of solar masses. [3] [4] Formation of quasi-stars could only happen early in the development of the Universe before hydrogen and helium were contaminated by heavier elements; thus, they may have been very massive Population III stars. [5] Such stars would dwarf VY Canis Majoris, UY Scuti, and Stephenson 2 DFK 1 also known as Stephenson 2-18, three among the largest known modern stars.

Once the black hole had formed at the protostar's core, it would continue generating a large amount of radiant energy from the infall of stellar material. This constant outburst of energy would counteract the force of gravity, creating an equilibrium similar to the one that supports modern fusion-based stars. [6] Quasi-stars would have had a short maximum lifespan, approximately 7 million years, [7] during which the core black hole would have grown to about 1,000–10,000 solar masses (2×1033–2×1034 kg). [1] [6] These intermediate-mass black holes have been suggested as the progenitors of modern supermassive black holes such as the one in the center of the Galaxy.

Quasi-stars are predicted to have had surface temperatures higher than 10,000 K (9,700 °C). [6] At these temperatures, each one would be about as luminous as a small galaxy. [1] As a quasi-star cools over time, its outer envelope would become transparent, until further cooling to a limiting temperature of 4,000 K (3,730 °C). [6] This limiting temperature would mark the end of the quasi-star's life since there is no hydrostatic equilibrium at or below this limiting temperature. [6] The object would then quickly dissipate, leaving behind the intermediate mass black hole. [6]

See also

Related Research Articles

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<span class="mw-page-title-main">NGC 1300</span> Galaxy in the constellation Eridanus

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<span class="mw-page-title-main">R136a2</span> Star in the constellation Dorado

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<span class="mw-page-title-main">NGC 1052</span> Elliptical galaxy in the constellation Cetus

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<span class="mw-page-title-main">NGC 4494</span> Galaxy in the constellation Coma Berenices

NGC 4494 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 4494 is about 60,000 light years across. It was discovered by William Herschel in 1785.

<span class="mw-page-title-main">NGC 5982</span> Galaxy in the constellation Draco

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<span class="mw-page-title-main">NGC 3665</span> Galaxy in the constellation Ursa Major

NGC 3665 is a lenticular galaxy located in the constellation Ursa Major. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that NGC 3665 is about 85,000 light years across. It was discovered by William Herschel on March 23, 1789.

<span class="mw-page-title-main">IC 1459</span> Elliptical galaxy in the constellation of Grus

IC 1459 is an elliptical galaxy located in the constellation Grus. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that IC 1459 is about 130,000 light-years across. It was discovered by Edward Emerson Barnard in 1892.

<span class="mw-page-title-main">NGC 2985</span> Galaxy in the constellation Ursa Major

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<span class="mw-page-title-main">NGC 4278</span> Galaxy in the constellation Coma Berenices

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<span class="mw-page-title-main">NGC 2974</span> Galaxy in the constellation Sextans

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<span class="mw-page-title-main">Direct collapse black hole</span> High-mass black hole seeds

Direct collapse black holes (DCBHs) are high-mass black hole seeds, putatively formed within the redshift range z=15–30, when the Universe was about 100–250 million years old. Unlike seeds formed from the first population of stars (also known as Population III stars), direct collapse black hole seeds are formed by a direct, general relativistic instability. They are very massive, with a typical mass at formation of ~105 M☉. This category of black hole seeds was originally proposed theoretically to alleviate the challenge in building supermassive black holes already at redshift z~7, as numerous observations to date have confirmed.

A Hawking star is a theoretical type of star, where the star's core contains a very small, substellar, primordial black hole, and is partially or completely powered by energy from matter accreting into the black hole, rather than stellar fusion. It is named for Stephen Hawking, who proposed the existence of primordial black holes.

References

  1. 1 2 3 Battersby, Stephen (29 November 2007). "Biggest black holes may grow inside 'quasistars'". NewScientist.com news service.
  2. ↑ Ball, Warrick H.; Tout, Christopher A.; Żytkow, Anna N.; Eldridge, John J. (2011). "The structure and evolution of quasi-stars". Monthly Notices of the Royal Astronomical Society. 414 (3): 2751–2762. arXiv: 1102.5098 . Bibcode:2011MNRAS.414.2751B. doi:10.1111/j.1365-2966.2011.18591.x.
  3. ↑ Yasemin Saplakoglu (29 September 2017). "Zeroing In on How Supermassive Black Holes Formed". Scientific American. Retrieved 8 April 2019.
  4. ↑ Mara Johnson-Goh (20 November 2017). "Cooking up supermassive black holes in the early universe". Astronomy. Retrieved 8 April 2019.
  5. ↑ Ball, Warrick H.; Tout, Christopher A.; Żytkow, Anna N.; Eldridge, John J. (1 July 2011). "The structure and evolution of quasi-stars: The structure and evolution of quasi-stars". Monthly Notices of the Royal Astronomical Society. 414 (3): 2751–2762. arXiv: 1102.5098 . Bibcode:2011MNRAS.414.2751B. doi: 10.1111/j.1365-2966.2011.18591.x .
  6. 1 2 3 4 5 6 Begelman, Mitch; Rossi, Elena; Armitage, Philip (2008). "Quasi-stars: accreting black holes inside massive envelopes". MNRAS. 387 (4): 1649–1659. arXiv: 0711.4078 . Bibcode:2008MNRAS.387.1649B. doi:10.1111/j.1365-2966.2008.13344.x. S2CID   12044015.
  7. ↑ Schleicher, Dominik R. G.; Palla, Francesco; Ferrara, Andrea; Galli, Daniele; Latif, Muhammad (25 May 2013). "Massive black hole factories: Supermassive and quasi-star formation in primordial halos". Astronomy & Astrophysics. 558: A59. arXiv: 1305.5923 . Bibcode:2013A&A...558A..59S. doi:10.1051/0004-6361/201321949. S2CID   119197147.

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