IT’S 35 MILLION LIGHT-YEARS AWAY and 50,000 light-years wide. It’s the spiral galaxy NGC 3521, a spectacular object with a bright and compact core or nucleus, surrounded by richly detailed spiral structure.
This new picture from the European Southern Observatory’s (ESO) Very Large Telescope shows that the most distinctive features of NGC 3521 are its long spiral arms, which are dotted with star-forming regions and interspersed with veins of dust.
The arms are rather irregular and patchy, making NGC 3521 a typical example of a ‘flocculent spiral galaxy’.
These types of galaxies have ‘fluffy’ spiral arms that contrast with the sweeping arms of ‘grand-design spirals’ such as the famous Whirlpool galaxy or M 51, discovered by Charles Messier.
NGC 3521 is bright and relatively close-by, and can easily be seen with a small telescope such as the one used by Messier to catalogue a series of hazy astronomical objects when he was searching for comets in the 1700s.
Strangely, the French astronomer seems to have missed this spiral even though he identified several other galaxies of similar brightness in the constellation of Leo.
It was only in the year that Messier published the final version of his catalogue, 1784, that another famous astronomer, William Herschel, discovered NGC 3521 early on in his more detailed surveys of the northern skies.
Through his larger, 47cm aperture, telescope, Herschel saw a “bright centre surrounded by nebulosity,” according to his observation notes.
In this new VLT picture, colourful, yet ill-defined spiral arms replace Herschel’s “nebulosity”. Older stars dominate the reddish area in the centre while young, hot blue stars permeate the arms further away from the core.
Download wallpapers of the spiral galaxy NGC 3521:
Adapted from information issued by ESO / O. Maliy.
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