NASA. LARGE FORMAT. DEEP SPACE. Stephan's... - Lot 230 - Vermot et Associés

NASA. LARGE FORMAT. DEEP SPACE. Stephan's quintet, visible in the constellation Pegasus, was discovered by astronomer Edouard Stephan in 1877. At the time, however, he reported the discovery of "new nebulae", as the concept of other galaxies beyond our own Milky Way was not formalized until the 1920s. Only four galaxies of the quintet initially discovered are physically linked. The first is around 40 million light-years away, instead of the 300 million light-years of the others. Three of these galaxies have distorted shapes, elongated spiral arms and long gaseous tidal tails containing star clusters, evidence of their close encounter. These interactions triggered a frenzy of star birth in the central pair of galaxies. The four galaxies bounded by gravity will merge into a single large galaxy in several million years' time. The galaxies in the middle of the group have already begun to merge with each other. The collision has brought out long tails of stars from each galaxy, triggering massive explosions of star-forming activity. These stars are less than 10 million years old and have not yet blown away their native clouds. The galaxy at bottom right is a normal-looking elliptical galaxy less affected by interactions. The most distant members of the quintet are distinctly redder than the foreground galaxy, suggesting that older stars reside in their cores. Starlight can also be made redder by dust raised during encounters. Vintage chromogenic print. Numbering on front. Label on back. 50.8 x 40.6cm with margins.