A tiny galaxy has been found hiding in orbit around the Milky Way
From the smell of Uranus, to the discovery of a second magnetic field around Earth, space is the gift that keeps on giving.
And the latest finding, spotted by a group of astronomers led by Sergey E. Koposov from Carnegie Mellon University, is a tiny dwarf galaxy orbiting our solar system which, until now, had managed to avoid detection.
The galaxy, named Hydrus 1 or the “snake in the clouds”, was discovered using the Dark Energy Camera (DECam) found on the Blanco Telescope in Chile. Lying between two other galaxies orbiting the Milky Way, the Small and Large Magellanic Clouds could join the former as being a prominent dwarf galaxy in the area.
Visible from Earth’s southern hemisphere, roughly 90,000 lightyears away from the sun, the researchers explain Hydrus 1 is a faint, mildly elliptical galaxy that stretches only about 326 lightyears across. By comparison, our own Milky Way galaxy is around 100,000 lightyears across.
“Hydrus 1’s velocity dispersion indicates the system is dark matter dominated, but its dynamical mass-to-light ratio is significantly smaller than typical for ultra-faint dwarfs at similar luminosity,” the researchers wrote in the paper.
With these parameters identified, the researchers suggest Hydrus 1 is likely a dwarf galaxy. The metal-poor nature of the stars in Hydrus 1 also points to this conclusion. However, there is a chance it could be a “globular” cluster of old stars.
One extremely carbon-enhanced and extremely metal-poor star observed is significant in the team’s discovery.
“This level of carbon enrichment makes it one of the most carbon-enhanced stars known in both the Milky Way halo and the dwarf galaxies,” the astronomers added.
They now hope to find out more about this strange dwarf galaxy by studying ESA’s Gaia Data Release. This data should shine a light on the connection between the Magellanic Clouds and Hydrus 1.