Tidal disruption event - Black holes and stars

[paulsutton]

Just reading an artcle about a black hole ripping a star apart due to its gravity.

https://scitechdaily.com/black-hole-tears-star-to-shreds-unleashing-cosmic-shockwaves/

Seems interesting, however I just wondered if this is a similar phenomenon that is mentioned in the Brian Cox series recently on BBC one where he mentions asteroids around planets also being pulled apart and forming rings.   As with the paper above, this new disk is also interacting with another star,

I think Professor cox talks about Phobos is going to one day break up,  some parts will burn up, however the rest will form a ring or rings around Mars.   So something similar is also happening on Saturn, where a moon is causing gaps in the rings.

Both do see similar, only clearly what happens with a black hole and star is on a massive scale by comparison.

 

Just asking

Paul

[swansont]

Yes it’s similar - it’s all gravitation - but, as you say, on a different scale.

[paulsutton]

Thanks,   interesting topic though,  So will the upcoming space based gravitation wave telescope help with our understanding? https://lisa.nasa.gov/

[Halc]

Tidal disruption (the breakup of moons that fall below the Roche limit) is essentially Newtonian physics and has been fairly well understood since the 19th century. It has little if anything to do with gravitational waves and more with physical stress on orbiting objects.

Earth for instance puts out a total energy of about 200 watts in the form of gravitational waves. It has plenty of tidal gradient to say destroy the moon if it ever gets close enough (it will be destroyed before this happens), but that 200 watts will not register on any detector we make.

Yes, an orbiting GW detector will presumably be more sensitive than LIGO, but would lack the redundancy of the multiple GW detectors on Earth unless they orbit several of them. Not sure how much redundancy is needed in space where trucks driving nearby are not going to trigger false positives.

[Mordred]

19 minutes ago, Halc said:

Tidal disruption (the breakup of moons that fall below the Roche limit) is essentially Newtonian physics and has been fairly well understood since the 19th century. It has little if anything to do with gravitational waves and more with physical stress on orbiting objects.

Earth for instance puts out a total energy of about 200 watts in the form of gravitational waves. It has plenty of tidal gradient to say destroy the moon if it ever gets close enough (it will be destroyed before this happens), but that 200 watts will not register on any detector we make.

Yes, an orbiting GW detector will presumably be more sensitive than LIGO, but would lack the redundancy of the multiple GW detectors on Earth unless they orbit several of them. Not sure how much redundancy is needed in space where trucks driving nearby are not going to trigger false positives.

The main advantage is the potential to detect longer wavelengths the arm length of LIGO can only accept a certain range. Longer arm detection range will allow detection of longer GW wavelengths much like that of an antenna for optimal detection is a quarter wavelength. LIGO however uses multiple beams to increase its sensitivity range. Though quite frankly any GW waves generated by Phobos is well out of any practical means of detection. 

Edited November 18 by Mordred