22.5 The evolution of more massive stars  (Page 4/28)

Key concepts and summary

In stars with masses higher than about 8 solar masses, nuclear reactions involving carbon, oxygen, and still heavier elements can build up nuclei as heavy as iron. The creation of new chemical elements is called nucleosynthesis. The late stages of evolution occur very quickly. Ultimately, all stars must use up all of their available energy supplies. In the process of dying, most stars eject some matter, enriched in heavy elements, into interstellar space where it can be used to form new stars. Each succeeding generation of stars therefore contains a larger proportion of elements heavier than hydrogen and helium. This progressive enrichment explains why the stars in open clusters (which formed more recently) contain more heavy elements than do those in ancient globular clusters, and it tells us where most of the atoms on Earth and in our bodies come from.

For further exploration

Articles

Balick, B.&Frank, A. “The Extraordinary Deaths of Ordinary Stars.” Scientific American (July 2004): 50. About planetary nebulae, the last gasps of low-mass stars, and the future of our own Sun.

Djorgovsky, G. “The Dynamic Lives of Globular Clusters.” Sky&Telescope (October 1998): 38. Cluster evolution and blue straggler stars.

Frank, A. “Angry Giants of the Universe.” Astronomy (October 1997): 32. On luminous blue variables like Eta Carinae.

Garlick, M. “The Fate of the Earth.” Sky&Telescope (October 2002): 30. What will happen when our Sun becomes a red giant.

Harris, W.&Webb, J. “Life Inside a Globular Cluster.” Astronomy (July 2014): 18. What would night sky be like there?

Iben, I.&Tutokov, A. “The Lives of the Stars: From Birth to Death and Beyond.” Sky&Telescope (December 1997): 36.

Kaler, J. “The Largest Stars in the Galaxy.” Astronomy (October 1990): 30. On red supergiants.

Kalirai, J. “New Light on Our Sun’s Fate.” Astronomy (February 2014): 44. What will happen to stars like our Sun between the main sequence and the white dwarf stages.

Kwok, S. “What Is the Real Shape of the Ring Nebula?” Sky&Telescope (July 2000): 33. On seeing planetary nebulae from different angles.

Kwok, S. “Stellar Metamorphosis.” Sky&Telescope (October 1998): 30. How planetary nebulae form.

Stahler, S. “The Inner Life of Star Clusters.” Scientific American (March 2013): 44–49. How all stars are born in clusters, but different clusters evolve differently.

Subinsky, R. “All About 47 Tucanae.” Astronomy (September 2014): 66. What we know about this globular cluster and how to see it.

Websites

BBC Page on Giant Stars: http://www.bbc.co.uk/science/space/universe/sights/giant_stars. Includes basic information and links to brief video excerpts.

Encylopedia Brittanica Article on Star Clusters: http://www.britannica.com/topic/star-cluster. Written by astronomer Helen Sawyer Hogg-Priestley.

Hubble Image Gallery: Planetary Nebulae: http://hubblesite.org/gallery/album/nebula/planetary/. Click on each image to go to a page with more information available. (See also a similar gallery at the National Optical Astronomy Observatories: https://www.noao.edu/image_gallery/planetary_nebulae.html).