New Model To Probe How Black Holes Rip Apart Starts

  • Scientists have found a model which can infer black hole mass, its spin by observing
    • How the stars are ripped apart on coming to the vicinity of these astronomical bodies with high gravitational force found at the centre of some massive galaxies.
  • Most black holes lead to isolated lives and are impossible to study. Astronomers study them by watching for their effects on nearby stars and gas.
    • Stars are disrupted when the black hole’s tidal gravity exceeds the star’s self-gravity, and this phenomenon is called tidal disruption events (TDE).
    • Supermassive black holes govern the movement of stars orbiting within their gravitational potential, and their tidal forces can disrupt or rip apart the stars that come to their vicinity.
    • Indian Institute of Astrophysics (IIA) scientists who had earlier calculated the rate of disruption and its statistics focused on
    • The observations of a given stellar disruption event (TDE) in their new study and inferred the black hole mass, star mass, and the point of closest approach of the star’s orbit.
  • The stars in a galaxy are captured and ripped apart about a few times in a million years.
  • The disrupted debris follows a Keplerian orbit and returns with a mass fallback rate that decreases with time.
  • The infalling debris interacts with the outflowing debris resulting in the circularization and the formation of an accretion disk – the temporary accumulation of matter outside the back hole before it dives into the black hole.
  • This emits in various spectral bands from X-ray, optical to infrared wavelengths.
  • The transient nature of TDE luminosity makes it an ideal laboratory to study the physics of an evolving accretion disk that includes the gas dynamics of the inflow, outflow, and the radiation.
  • The tidal disruption events are crucial and useful phenomena to detect and predict the mass of supermassive black holes in quiescent galaxies.
  • This time-dependent model by IIA provides insights into disk evolution in a black hole gravity.
  • By comparing the expected detection rate with the detection rate from observation, one can probe into black hole demographics.
  • The fits to the observations yield parameters of the star and the black hole that are useful for the statistical studies and build the demographics of black holes.