The Hubble Space Telescope observes Terzan 12 | Sci News

Astronomers using the NASA/ESA Hubble Space Telescope captured a stunning image of the globular cluster Terzan 12, a large, tightly bound collection of stars in the constellation Sagittarius.

This Hubble image shows Terzan 12, a globular cluster about 15,000 light years away in the constellation of Sagittarius. Image credit: NASA / ESA / Hubble / R. Cohen, Rutgers University.

Stable, dense globular clusters gather hundreds of thousands or millions of stars, gravitationally bound into a single structure about 100-200 light-years across. The word globulefrom which these groups take their name, is the Latin for a small sphere.

They are among the oldest known objects in the Universe and are remnants of the earliest times of creation in the universe.

Our own Milky Way Galaxy hosts at least 150 globular clusters and a few more may be hidden behind the galaxy’s thick disk.

Hubble astronomers said: “Groups of globules are common in the Milky Way.

About 150 are known, mostly from its outer halo, and Hubble has been studying them since it was launched in 1990.

However, examining clusters like Terzan 12, which is heavily obscured by interstellar dust, is complicated by the redness of the light.”

They say: “When starlight passes through an interstellar cloud it can be absorbed and scattered by dust particles.

“The strength of this scattering depends on the wavelength of the light, with shorter wavelengths being scattered and absorbed strongly.”

“This means that the blue light waves from the stars are unlikely to pass through the cloud, making the background stars appear redder than they really are.”

“We refer to the color change caused by the scattering and absorption of the star’s light as red, and it is responsible for the bright array of colors in the new image of Terzan 12.”

“Relatively unobscured stars shine brightly in white and blue, while crawling clouds of gas and dust blanket much of Terzan 12, giving the stars a dark red color.”

The more dust along our line of sight in a cluster, the redder the star’s brightness.

Terzan 12, known as ESO 522-1, is located about 15,000 light years away in the constellation of Sagittarius.

This group was discovered by the Turkish-Armenian astronomer Agop Terzan about half a century ago.

There were only 11 groups found by Terzan. Mixing results in a mistake made by Terzan in 1971, when he rediscovered Terzan 5 – a group he had already discovered and described in 1968 – and called it Terzan 11.

Terzan tried to correct his mistake, but the confusion caused by continuing scientific studies since then, astronomers decided to conclude that there is no Terzan 11.

“Some of the stars in the Terzan 12 photo appear to be very different in color from their nearest neighbors,” the astronomers said.

“The brightest red stars are bloated, old giants, many times larger than our Sun.” They lie between the Earth and the group. Only a few can be members of the group.”

“The hottest, greenest stars are along the line of sight and are not within the cluster, which only contains aging stars.”

“The red light of stars is often a problem for astronomers, so we were able to rule out the effect of gas and dust by comparing the new observations with the sharp field of view of Hubble’s Advanced Camera for Surveys (ACS) and Wide-Field Camera 3 (WFC3) with existing images.”

“These observations should shed light on the relationship between the age and composition of globular clusters within the Milky Way, compared to how we understand clusters spread throughout our Galaxy.”