Table of Contents
- 1 Which stars are brightest in an aging globular cluster?
- 2 Do the stars in a globular cluster have similar or different ages?
- 3 What is the oldest cluster?
- 4 Where are globular star clusters?
- 5 Why are globular clusters older than open clusters?
- 6 What is the age of the cluster?
- 7 How old are the oldest stars in the Milky Way?
- 8 Why are globular clusters so old?
- 9 What is the average star density in a globular cluster?
- 10 Are there any stars larger than the Sun in a cluster?
Which stars are brightest in an aging globular cluster?
Globular clusters are extremely luminous objects. Their mean luminosity is the equivalent of approximately 25,000 Suns. The most luminous are 50 times brighter. The brightest stars are the red giants, bright red stars with an absolute magnitude of −2, about 600 times the Sun’s brightness, or luminosity.
Do the stars in a globular cluster have similar or different ages?
Since globular clusters form at once from a single giant molecular cloud, a cluster’s stars have roughly the same age and composition.
Which type of cluster has the oldest stars?
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 is the oldest cluster?
NGC 121 is around 10 billion years old, making it the oldest cluster in its galaxy; all of the SMC’s other globular clusters are 8 billion years old or younger.
Where are globular star clusters?
Globular clusters orbit in the halo of our galaxy, centered on the galaxy’s center and expanding above and below the galactic disk. Open star clusters tend to orbit within the disk. Globular star clusters contain hundreds of thousands of stars, and some – like Omega Centauri, shown above – contain millions of stars.
How can you tell how old a globular cluster is?
By placing the stars in a globular cluster on a Hertzprung-Russell diagram, astronomers can determine the cluster’s age by looking at the main sequence turnoff point and comparing it with models of stellar evolution.
Why are globular clusters older than open clusters?
The higher up the main sequence, the more massive the star is. As globular clusters are generally much older than open clusters their colour-magnitude diagrams show more evolved stars. They also have no high-mass stars left on the main sequence.
What is the age of the cluster?
By studying where the main sequence turnoff is and how far the stars that are no longer on the main sequence have evolved, scientists arrive at the cluster’s age of 13.4 billion years. It’s also worth noting that the time light requires to reach us from the cluster doesn’t have much impact on the age we measure.
How old is the 47 Tucanae star cluster?
10.5 billion years old
47 Tucanae is 10.5 billion years old and is one of the brightest of our Milky Way galaxy’s more than 150 globular clusters.
How old are the oldest stars in the Milky Way?
HE 1523-0901 is the oldest known star in our galaxy, the Milky Way. The star’s estimated age is about 13.2 billion years.
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.
What is a globular cluster?
Globular Clusters are symmetrical systems of up to a million stars formed about 13 to 15 billion years ago, and as such they are the oldest surviving stellar subsystems in galaxies.
What is the average star density in a globular cluster?
General information on Globular Clusters. The average star density in a Globular Cluster is about 0.4 stars per cubic parsec. In the dense center of the cluster, the star density can increase from 100 to 1000 per cubic parsec.
Are there any stars larger than the Sun in a cluster?
By now, the only stars still remaining in the main cluster have masses comparable to that of the Sun or less. In some clusters, such as M67, however, the giant stars are brighter than the brightest main stars, and must have become brighter during their evolution.
What is the brightest cluster in the Andromeda Galaxy?
One of the brightest known clusters in our Galaxy is w Centauri, and the brightest known cluster in the galaxy of Andromeda is the M2 cluster. Using Colour-Magnitude graphs. A way of analysing globular clusters is to use Colour-Magnitude diagrams.