When William Herschel began his comprehensive survey of the sky using large telescopes in 1782, there were 34 known globular clusters. Herschel discovered another 36 and was the first to resolve virtually all of them into stars.

When was the first star cluster discovered?

The first record of a globular cluster, in the constellation Sagittarius, dates to 1665 (it was later named Messier 22); the next, Omega Centauri, was recorded in 1677 by the English astronomer and mathematician Edmond Halley.

Who discovered the Hercules cluster?

The Great Globular Cluster – Messier 13 (M13, NGC 6205)

It is approximately 22,200 light years distant. The Hercules Globular Cluster was discovered by the English astronomer Edmond Halley in 1714 and included in Messier's catalogue as Messier 13 on June 1, 1764.

What is globular star clusters in astronomy?

globular cluster, a large group of old stars that are closely packed in a symmetrical, somewhat spherical form. Globular clusters, so called because of their roughly spherical appearance, are the largest and most massive star clusters.

What is the oldest globular cluster?

A team of astronomers using the Gemini-South telescope has discovered one of the oldest stellar clusters in the Milky Way. The team's results date the globular cluster, named HP 1, at about 12.8 billion years, making its stars among the oldest ever found in our Galaxy.

What are Globular Clusters? Relics of the Early Universe

34 related questions found

How old is a globular cluster?

Most are estimated to be at least 10 billion years old, and contain some of the oldest stars in the galaxy. The clusters likely formed very early, before the galaxy flattened into a spiral disc.

How are blue stragglers created?

The most likely explanation is that blue stragglers are the result of stars that come too close to another star or similar mass object and collide. The newly formed star has thus a higher mass, and occupies a position on the HR diagram which would be populated by genuinely young stars.

Where are globular clusters found?

Globular star clusters are known to be located mostly in the great spherical halo of the Milky Way. Spiral galaxies like our Milky Way contain stars, gas and dust, mostly organized into a flat disk containing the spiral arms, but with the addition of a more rounded bulge and halo, centered on the galaxy's center.

Do globular clusters have planets?

Because globular clusters are deficient in heavier elements, some astronomers have long believed that globular clusters cannot contain planets. ... Hubble revealed that the planet is in an unlikely place. It orbits two captured stars: a helium white dwarf and a rapidly spinning neutron star near the core of M4.

How many stars are in a globular cluster?

Globular clusters are big. They can reach 300 light-years in diameter and contain 10 million stars.

Who discovered M13?

The English astronomer Edmond Halley, best known for recognizing the periodicity of the comet that bears his name, discovered M13 in 1714. When Charles Messier added M13 to his catalog in 1764, he was convinced that the nebulous object did not contain any stars at all.

Why are globular clusters so old?

It is thought that globular clusters formed very early in the vast halo surrounding the nascent galaxy before it flattened to form the spiral disc. Star formation would have stopped in these clusters maybe 13 billion years ago, so only old stars are expected to be found there.

Why are globular clusters found in the halo?

The halo is home to some ancient star clusters, known as globular clusters. They are known to be old because their stars contain low levels of heavy elements, which weren't present in the young universe and were built up over time in supernovae. The clusters move about the galactic nucleus in (nearly) random orbits.

What is a globular cluster quizlet?

A globular cluster is. a cluster of hundreds of thousands of stars found in our own galaxy.

What color are globular clusters?

The brightest stars in a globular cluster are those at the tip of the red giant branch in the HR diagram, which explains the red appearance of the bright stars in color images of the clusters, like the one above.

Do globular clusters have black holes?

More importantly, scientists think that a globular cluster is an ideal place to find medium-sized black holes because of the dense collection of stars at their cores. Globular clusters are large spherical collections of stars that orbit on the peripheries of galaxies.

How close are stars in globular cluster?

The typical distance between stars in a globular cluster is about 1 light year, but at its core the separation between stars averages about a third of a light year—13 times closer than Proxima Centauri, the closest star to the Sun. Globular clusters are thought to be unfavorable locations for planetary systems.

What are clusters of stars called?

A star cluster is a group of stars that share a common origin and are gravitationally bound for some length of time. ... The two basic categories of stellar clusters are open clusters, also known as galactic clusters, and globular clusters.

How are star clusters formed?

Star Clusters. When stars are born they develop from large clouds of molecular gas. This means that they form in groups or clusters, since molecular clouds are composed of hundreds of solar masses of material. After the remnant gas is heated and blow away, the stars collect together by gravity.

What is an interesting fact about globular clusters?

Globular clusters are fairly common: there are about 150 to 158 known globular clusters in the Milky Way. Large galaxies can have more: Andromeda may have as many as 500. Some giant elliptical galaxies, particularly those at the centres of galaxy clusters, such as M87, have as many as 13,000 globular clusters.

Why is it odd to find blue stars in globular clusters?

Blue stragglers are a class of star observed in old, dense stellar systems such as globular clusters. They stand out because old stellar populations are expected to be devoid of blue (high-mass) stars which possess very short lifespans.

Why are blue stragglers surprising?

Blue stragglers are unusual that they are bigger and bluer than the rest of the stars (See picture for reference). ... They also have masses two to three times that of the other stars. This suggests that they were formed from two or three stars which collided and merged.

Where are blue stragglers found?

"Blue Stragglers" are unusually hot and bright stars found in the cores of ancient star clusters known as globulars. Globular clusters are located in galactic halos, of which the Milky Way may have from 180 to 200, or more.