Hubble Views Lonely Dwarf Galaxy: NGC 1156

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Hubble Views Lonely Dwarf Galaxy: NGC 1156
Sci News Staff | 8 July 2019

The NASA/ESA Hubble Space Telescope has produced a beautiful image of the dwarf irregular galaxy NGC 1156, one of the best targets to study the isolated dwarf galaxies in the nearby Universe.​

This image snapped by the NASA/ESA Hubble Space Telescope reveals a detailed view of NGC 1156. The color image was made from separate exposures taken in the visible region of the spectrum with Hubble’s Advanced Camera for Surveys. Two filters were used to sample various wavelengths. The color results from assigning different hues to each monochromatic image associated with an individual filter. Image credit: NASA / ESA / Hubble / R. Jansen.

NGC 1156, also known as LEDA 11329, UGC 2455 and IRAS 02567+2502, is located in the constellation Aries, some 25 million light-years from Earth.

The galaxy was discovered on November 13, 1786 by the German-born British astronomer William Herschel.

NGC 1156 is one of the highly isolated and less disturbed galaxies, and its nearest neighbors are UGC 2684 and UGC 2716.

It is classified as a dwarf irregular galaxy, meaning that it lacks a clear spiral or rounded shape, as other galaxies have, and is on the smaller side, albeit with a relatively large central region that is more densely packed with stars.

Some pockets of gas within NGC 1156 rotate in the opposite direction to the rest of the galaxy, suggesting that there has been a close encounter with another galaxy in the past.

The gravity of this other galaxy — and the turbulent chaos of such an interaction — could have scrambled the likely more orderly rotation of material within NGC 1156, producing the odd behavior.

“NGC 1156 resembles a delicate cherry blossom tree flowering in springtime,” Hubble astronomers said.

“The many bright ‘blooms’ within the galaxy are in fact stellar nurseries — regions where new stars are springing to life.”

“Energetic light emitted by newborn stars in these regions streams outwards and encounters nearby pockets of hydrogen gas, causing it to glow with a characteristic pink hue.”