Spinning black hole swallowing star

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Dec 12, 2016.

  1. paddoboy Valued Senior Member

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    Spinning black hole swallowing star explains superluminous event
    December 12, 2016

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    This artist's impression depicts a sun-like star close to a rapidly spinning supermassive black hole, with a mass of about 100 million times the mass of the sun, in the center of a distant galaxy. Its large mass bends the light from stars and gas behind it. Despite being way more massive than the star, the supermassive black hole has an event horizon which is only 200 times larger than the size of the star. Its fast rotation has changed its shape into an oblate sphere.The gravitational pull of the supermassive black hole rips the the star apart in a tidal disruption event. In the process, the star was "spaghettified" and shocks in the colliding debris as well as heat generated in accretion led to a burst of light. Credit: ESO, ESA/Hubble, M. Kornmesser

    In 2015, the All Sky Automated Survey for SuperNovae (ASAS-SN) detected an event, named ASASSN-15lh, that was recorded as the brightest supernova ever—and categorised as a superluminous supernova, the explosion of an extremely massive star at the end of its life. It was twice as bright as the previous record holder, and at its peak was 20 times brighter than the total light output of the entire Milky Way.



    Read more at: http://phys.org/news/2016-12-black-hole-swallowing-star-superluminous.html#jCp
     
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  3. paddoboy Valued Senior Member

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    http://www.nature.com/articles/s41550-016-0002

    The superluminous transient ASASSN-15lh as a tidal disruption event from a Kerr black hole


    Abstract
    When a star passes within the tidal radius of a supermassive black hole, it will be torn apart1. For a star with the mass of the Sun (M ⊙) and a non-spinning black hole with a mass <108 M ⊙, the tidal radius lies outside the black hole event horizon2 and the disruption results in a luminous flare3–6. Here we report observations over a period of ten months of a transient, hitherto interpreted7 as a superluminous supernova8. Our data show that the transient rebrightened substantially in the ultraviolet and that the spectrum went through three different spectroscopic phases without ever becoming nebular. Our observations are more consistent with a tidal disruption event than a superluminous supernova because of the temperature evolution6, the presence of highly ionized CNO gas in the line of sight9 and our improved localization of the transient in the nucleus of a passive galaxy, where the presence of massive stars is highly unlikely10,11. While the supermassive black hole has a mass >108 M ⊙ 12,13, a star with the same mass as the Sun could be disrupted outside the event horizon if the black hole were spinning rapidly14. The rapid spin and high black hole mass can explain the high luminosity of this event.

    more at link................
     
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  5. danshawen Valued Senior Member

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    A pity LIGO was not yet online to see any gravity waves produced by that event. Or wasn't it? What was the exact date and time stamp of the supernova event?

    I believe you once predicted it would spaghettify while undergoing a deep redshift. What could have gone wrong? Not massive enough? Too massive? Was relative velocity a factor in increasing its mass? Why did the energy of the star totally convert to energy and supernova before contact with the event horizon?
     
    Last edited: Dec 16, 2016
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  7. paddoboy Valued Senior Member

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    As alluded to in the abstract, tidal forces of a BH can certainly be effective outside the EH/Schwarzchild radius.
     
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  8. danshawen Valued Senior Member

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    Yes, and that tidal process would pump more mass/energy into the supernova event as well, but I doubt tidal mechanical forces alone would be sufficient to effect supernova conversion because most of a star is already plasma. How much hotter would the plasma need to get to induce a reaction of higher radiant luminosity than our entire galaxy?
     

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