Hints of a spiral structure embedded in a circular halo of stars
Space news (February 1, 2016) – 300 million light-years away in the Bootes constellation –
Astronomers use the Hubble Tuning Fork to classify galaxies viewed during the human journey to the beginning of space and time according to their morphology. Devised by noted astronomer Edwin Hubble during the early part of the twentieth century, this galaxy classification system breaks galaxies into two general categories; elliptical and spiral galaxies.
Island universes viewed that don’t seem to fit into the two general categories of galaxies are considered irregular galaxies. Irregular galaxies have a more varied look than the general categories, often with a spiral structure that looks disturbed or disrupted. It’s this disrupted structure, and other hints, that makes astronomers think the more chaotic and varied look of these island universes could often be due to titanic collisions between galaxies.
The galaxy viewed in the image above is Mrk 820 (also LEDA 52404 or IRAS F14379+3142), a lenticular galaxy in the transition zone between the two general categories of galaxies (Type S0). Astronomers looking closer at his spectacular island universe believe it shows hints of spiral arms imprinted on a halo of stars, which is unusual for lenticular galaxies. Lenticular galaxies generally have a notable central bulge and disk, but no spiral arms.
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