Feeling Blue: Hubble Spots ‘Lonely’ Dwarf Galaxy 100 Million Light-Years Away

This week, Hubble set its sights on a blue dwarf galaxy in the Corona Australis constellation.

Image of the blue dwarf galaxy ESO 338-4.
ESA / Hubble & NASA

This week, Hubble set its sights on a blue dwarf galaxy in the Corona Australis constellation.

The Hubble Space Telescope is back in action. After a short hiatus from science work, the spacecraft has been keeping busy by studying intriguing swaths of the sky.

Last week, the telescope imaged a strong-lensing galaxy cluster and found a smiling face hidden among the stars, as reported by the Inquisitr. This week, Hubble cast its inquisitive lenses over the constellation of Corona Australis (the “Southern Crown”) and encountered a very different sight that seems to mirror the complete opposite sentiment.

According to NASA, Hubble stumbled upon a “lonely” little galaxy known as ESO 338-4 — a blue dwarf galaxy floating 100 million light-years from Earth.

Imaged by Hubble’s Wide Field Camera 3 instrument — one of the two primary cameras on board the space telescope — ESO 338-4 is what astronomers describe as a blue compact dwarf galaxy. These small galaxies are made up of large clusters of young, massive stars that burn intensely in vivid shades of blue — making the entire galaxy don an azure apparel.

“Blue compact dwarf galaxies take their name from the intensely blue star-forming regions that are often found within their cores,” explained NASA officials. “One such region can be seen embedded in ESO 338-4, which is populated with bright, young stars voraciously consuming hydrogen.”

The image of ESO 338-4 was shared on Twitter by the Hubble team earlier today. As Sci-News points out, the color photo was created from different exposures captured by three Hubble instruments in visible, ultraviolet, and infrared light.

The blue stars which can be seen sparkling in the center of the snapshot were forged during a recent tempestuous event. Their birth is the result of a violent galactic merger that left a deep mark on the dwarf galaxy, disrupting the clouds of rich material around ESO 338-4.

Ignited by the turbulent encounter, the dust and gas clouds enshrouding the dwarf galaxy entered a frenzied star-forming state, churning out a new generation of stars at a rapid rate.

“These massive stars are doomed to a short existence, despite their vast supplies of hydrogen fuel. The nuclear reactions in the cores of these stars will burn through these supplies in only millions of years — a mere blink of an eye in astronomical terms.”

ESO 338-4 isn’t Hubble’s first encounter with a blue compact dwarf galaxy. In 2012, the telescope captured a dazzling photo of a blue dwarf called UGC 5497, a small galaxy tucked inside the Ursa Major constellation (the “Big Bear).

Image of a blue compact dwarf galaxy photographed by Hubble.
Blue compact dwarf galaxy UGC 5497. ESA/Hubble & NASA (CC BY 4.0)

Located significantly closer to home, this dwarf galaxy lies just 12 million light-years from Earth, notes the Hubble Space Telescope webpage.

Three years ago, the space telescope caught a glimpse of another blue compact dwarf, found 45 million light-years from Earth in the Bootes constellation (the “Herdsman”). Dubbed PGC 51017, this blue dwarf is populated by a bizarre group of stars that are much older than previously believed. A photo of this dwarf galaxy is available on the Hubble Space Telescope website, along with some details on its puzzling nature.