Table of Contents
- 1 How do astronomers know that globular clusters are made up of old stars?
- 2 What is true about globular clusters?
- 3 Why do we think that globular clusters contain the oldest stars in the galaxy?
- 4 How do astronomers know that globular clusters are very old quizlet?
- 5 How do astronomers know that stars and their planetary systems form from concentrations of interstellar material?
- 6 How do astronomers use the main sequence to determine ages of stellar clusters quizlet?
- 7 How do astronomers know how stars form?
- 8 How are globular clusters used to estimate the age of the universe?
- 9 How old is the universe compared to the oldest stars?
How do astronomers know that globular clusters are made up of old stars?
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.
What is true about globular clusters?
Globular clusters are densely packed collections of ancient stars. Roughly spherical in shape, they contain hundreds of thousands, and sometimes millions, of stars. Studying them helps astronomers estimate the age of the universe or figure out where the center of a galaxy lies.
Why do we think that globular clusters contain the oldest stars in the galaxy?
Globular clusters are tightly packed, symmetrical collections of stars, orbiting mostly in the extended star halos surrounding most spiral galaxies. Globular clusters contain some of the oldest stars in a galaxy and are thought to have formed early in its history. The heavier elements were forged in star interiors.
What type of stars are found in globular clusters?
Globular clusters are generally composed of hundreds of thousands of low-metal, old stars. The type of stars found in a globular cluster are similar to those in the bulge of a spiral galaxy but confined to a spheroid in which half the light is emitted within a radius of only a few to a few tens of parsecs.
Why do astronomers believe that most globular clusters are made of old stars?
Why do astronomers believe that most globular clusters are made of old stars? they have high amounts of heavy elements that newer stars like the sun do not have. Therefore larger stars use all of their fuel faster than low mass stars and do not live as long.
How do astronomers know that globular clusters are very old quizlet?
How do astronomers know that globular clusters are very old? The turnoff point tells the astronomer the age of the star cluster.
How do astronomers know that stars and their planetary systems form from concentrations of interstellar material?
Emission nebulae have been shown to contain young stars. How do astronomers know that stars (and their planetary systems) form from concentrations of interstellar material? They create shock waves that compress the surrounding gas and trigger collapse.
How do astronomers use the main sequence to determine ages of stellar clusters quizlet?
because all of a clusters’s stars were born at the same time, we can measure a cluster’s age by finding the main-sequence turnoff point on an H-R diagram of its stars. The cluster’s age is equal to the hydrogen-fusion lifetime of the hottest, most luminous stars that remain on the main sequence.
What is the relationship between globular clusters and Milky Way?
So the globular clusters (which contain very old stars) reveal a spherical component of the Milky Way, while the open clusters and other young stars and star-forming regions reveal a disk-shaped component of the Milky Way.
What characteristic of Cepheid variables makes them extremely useful to astronomers quizlet?
What characteristic of Cepheid variables makes them extremely useful to astronomers? The absolute magnitude of Cepheid variables is related directly to their period of pulsation.
How do astronomers know how stars form?
Astronomers in the US believe they have figured out how stars form from clouds of gas. Instead, stars form by fragmentation, and the fragmentation process determines their masses.”
How are globular clusters used to estimate the age of the universe?
Globular Clusters are a dense collection of roughly a million stars. Since all of the stars in a globular cluster formed at roughly the same time, they can serve as cosmic clocks. This way of estimating the age of the universe is based on our understanding of the life cycles of stars. The life of a star depends upon its mass.
How old is the universe compared to the oldest stars?
If we compare the various age determinations, there is a potential problem. If the astronomers who estimate that 1/H0 is as small as 10 billion years are correct, then the age of the universe would be less than the age of the oldest stars.
Why is there uncertainty in the age of the universe?
The uncertainty in this estimate is due to the difficulty in determining the exact distance to a globular cluster and in our ignorance of some of the details of how stars evolve. An alternative approach to estimate is the age of the universe is to measure the “Hubble constant”.
Which is brighter a high mass star or a low mass star?
High mass stars are much brighter than low mass stars; they rapidly burn through their supply of hydrogen fuel. A star like the Sun has enough fuel in its core to burn at its current brightness for approximately 9 billion years. A star that is twice as massive as the Sun will burn through its fuel supply in only 800 million years.