In a previously mentioned conceptual objective, I wrote about astronomers that found a black hole within a globular cluster tearing apart a white dwarf. This gruesome action was completed without remorse for this already dead star. As discussed in this lecture, white dwarfs are the results of low mass stars, much like our own, that burn up all their energy from nuclear fusion and later eject their outer layers and leave behind this small, compact star in its place. I wanted to take the time and appreciate this article from another point related to its subject.
In lecture, we covered material on how stars live out their lifetimes. Beginning with a cloud of gases, gravity pulls particles in until the star can create its own energy through nuclear fusion. Stars with higher mass contract into less space before fusion because they needed higher core temperatures to form and in turn became larger in radius, greater in luminosity, and hotter on the surface, causing them to live shorter than the sun. Meanwhile, smaller stars in the main sequence needed lower temperatures to begin nuclear fusion, making them smaller in radius, lower in surface temperature, lower in luminosity, and lower core temperature, causing them to exhaust their fuel much slower than our sun and stars larger than it. According to this article, the star that was being ripped apart brutally was one of such stars with a low mass. When it comes to star evolution and death, there comes a point in which a star will exhaust out of fuel. This stage is marked the star becoming a Red Giant, as its core shrinks due to the exhaustion of hydrogen atoms and its outer-layer to expand due to hydrogen shell fusion within that area. Once a star hits this stage, a few things can happen. In a Lecture-Tutorial we completed in class, we learned that that a small mass star ejects its outer layers creating a planetary nebula and leaves a white dwarf at its core. Oppositely, a red giant with a large mass will cause a supernova, and, depending on the original mass of the star, will either leave behind a neutron star (if small mass) or a black hole (if large mass).
In comparison to the article, I find it ironic that the small white dwarf was potentially picked on by what was left over by the death of a star much larger than it. I feel like if the stars were equivalent to people, then the black hole is a melodramatic bully that feels like they have to suck the life out of others to survive. Talk about high school drama in the sky, am I right?
Source: Bad Astronomy