Globular cluster hr diagram

To discuss the properties of globular clusters. To illustrate some of the stages of stellar evolution. To measure the Hertzsprung-Russell (colour-magnitude) diagram for the globular cluster NGC 104. To estimate the apparent magnitude of the Horizontal Branch and hence the distance to the cluster. Use the data to make an H-R diagram of the globular cluster.

Put the r magnitude on the y-axis and the g-r color on the x-axis. Try to take stars only from the cluster. Stars that appear dramatically different may be at different distances along the same line of sight. You should also be careful not to accidentally record the information for a. The HR diagram for a typical globular cluster looks very different than that of an open cluster. There are no Main Sequence stars of types OBAF, but there are many red giants.

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. Clusters like the Pleiades lie deep within our galaxy. This view is great for seeing distant galaxies and quasars, but it is not very good for seeing star clusters.

The Hertzsprung-Russell Diagram for stars of the globular cluster Tuc 47. In the image above, you can see a schematic HR diagram with. Interpreting the HR diagram of stellar clusters Stars are created deep within giant molecular clouds. When we look at such regions, we often see not just one, but a whole bunch of stars forming together.

In fact, it seems that stars are usually born in big groups, as members of a cluster of stars. All the stars in the cluster form at about the. In this video, the stars in globular cluster Omega Centauri are rearranged according to their intrinsic brightness (vertical axis) and their temperature (horizontal axis).

This differs from the HR diagram of stars near the Sun, which lumps together stars of differing ages and origins. Star clusters may be open clusters or globular clusters. The SDSS, on the other han looks primarily above and below the plane of the galaxy. Photometry means measurement of brightness.

Most stars occupy the region of the H-R diagram along a band called the main sequence. If you wait for about seconds, it will disappear, showing you the control panel of the Virtual Educational Observatory. Cluster HR Diagrams : Since all the stars in a cluster formed at the same time, they are all the same age. A very young cluster will have a HR diagram with a cluster of T-Tauri stars evolving towards the main sequence. As time passes the most massive stars at the top of the main sequence evolve into red giants.

This is the HR diagram for stars in a 12-billion-year-old globular cluster. Based on our understanding of stellar lives, which of the four labeled stars is currently generating energy through hydrogen fusion in a shell around an inert (non-burning) helium core. Both are types of star clusters , but the major differences come down to the age of the stars found within them, where they can be found in a galaxy and their shape.

As their name suggests, globular clusters are globule-shaped balls of hundreds of thousands of stars all crammed into an area a few hundred light years across. Thanks to Pat Morris at Leeds University, Davison Soper at Oregon and Harmut Frommert and SEDS for some of the plots and text used in the background of this experiment. Globular clusters , Zeilik, Ch 16. Any high-mass stars born in the globular cluster have already left the main sequence. Roughly spherical in shape, they contain hundreds of thousands, and sometimes millions, of stars.

Studying them helps astronomers. As the position of each star in the HR diagram varies with age, the shape of the curve for a globular cluster can be used to measure the overall age of the collected stars. The most massive main sequence stars in a globular cluster will also have the highest absolute magnitude, and these will be the first to evolve into the giant star stage.