Globular cluster M 13

Globular cluster M13, also known as Hercules, is one of the most famous and brightest globular clusters in the sky. It is located in the constellation Hercules and is an amazing astronomical structure. In 1974, when the Arecibo observatory opened, a radio message about Earth was sent in the direction of M13.

Globular clusters are groups of old stars gathered in tight spherical clusters. M13 consists of about 300,000 stars, which are packed into a relatively small space with a diameter of about 145 light-years.

Technical details about M13

M13 has a brightness of about 5.8 stellar magnitude, making it visible to the naked eye in dark skies. However, obtaining more detailed data on its stars and structure requires the use of high-resolution telescopes.

M13 is considered to be one of the oldest objects in our galaxy, with an estimated age of 11.7 billion years. This makes it a valuable object for studying stellar evolution and galaxy structure. The stars in M13 are predominantly of older generations, and studying their properties allows us to better understand the processes of star formation and evolution.

Discovery and Visibility

M13 was discovered by Edmond Halley in 1714, and Charles Messier added to his catalog in 1764. It lies at right ascension 16h 41.7m and declination +36° 28'. M13 is often described by astronomers as the most magnificent globular cluster visible to northern hemisphere observers.

M13 can be seen with binoculars as a bright, round spot of light. It is about 23 arcminutes in diameter, and is easily seen with small telescopes. A telescope as small as 4 inches in diameter can resolve the stars in the outer portion of M13, while larger telescopes can resolve the stars in the central portion.

Characteristics of M13

M13 is made up of several hundred thousand stars, with estimates ranging from 300,000 to over half a million. The brightest star in the cluster is the red giant variable star V11 (or V1554 Herculis) with an apparent magnitude of 11.95. M13 is between 22,200 and 25,000 light-years away from Earth and is one of more than 100 globular clusters that orbit the center of the Milky Way.

The stars in M13 are Population II, meaning they are significantly metal-poor compared to younger stars like the Sun. Overall, M13 contains only about 4.6% as much iron as the Sun.

Arecibo Radio Message

The Arecibo message of 1974, which contained encoded information about the human race, DNA, atomic numbers, the position of the Earth, and other information, was transmitted from the Arecibo radio telescope toward M13. The cluster's inclination was chosen because it was a large and relatively nearby cluster of stars observable at the time the experiment was conducted.

Stellar Composition Features

The stars in M13 form such dense structures that they sometimes collide with each other and can form new stars. These new stars, known as "blue wanderers", are of particular interest to astronomers.