{"id":572,"date":"2022-03-02T16:54:15","date_gmt":"2022-03-02T16:54:15","guid":{"rendered":"https:\/\/pressbooks.ccconline.org\/astronomy\/?post_type=part&p=572"},"modified":"2022-03-02T16:54:15","modified_gmt":"2022-03-02T16:54:15","slug":"chapter-18-the-stars-a-celestial-census","status":"publish","type":"part","link":"https:\/\/pressbooks.ccconline.org\/astronomy\/part\/chapter-18-the-stars-a-celestial-census\/","title":{"raw":"Chapter 18 The Stars: A Celestial Census","rendered":"Chapter 18 The Stars: A Celestial Census"},"content":{"raw":"
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\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1312\"]\"Image Figure\u00a018.1<\/strong>\u00a0Variety of Stars.\u00a0Stars come in a variety of sizes, masses, temperatures, and luminosities. This image shows part of a cluster of stars in the\u00a0Small Magellanic Cloud\u00a0(catalog number NGC 290). Located about 200,000 light-years away, NGC 290 is about 65 light-years across. Because the stars in this cluster are all at about the same distance from us, the differences in apparent brightness correspond to differences in luminosity; differences in temperature account for the differences in color. The various colors and luminosities of these stars provide clues about their life stories. (credit: modification of work by E. Olszewski (University of Arizona), European Space Agency, NASA)[\/caption]<\/figure>\r\n<\/div>\r\n
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Chapter Outline<\/h3>\r\n
18.1<\/span>\u00a0A Stellar Census<\/span><\/div>\r\n
18.2<\/span>\u00a0Measuring Stellar Masses<\/span><\/div>\r\n
18.3<\/span>\u00a0Diameters of Stars<\/span><\/div>\r\n
18.4<\/span>\u00a0The H\u2013R Diagram<\/span><\/div>\r\n<\/div>\r\n
\r\n

How do stars form? How long do they live? And how do they die? Stop and think how hard it is to answer these questions.<\/p>\r\n

Stars live such a long time that nothing much can be gained from staring at one for a human lifetime. To discover how stars evolve from birth to death, it was necessary to measure the characteristics of many stars (to take a celestial census, in effect) and then determine which characteristics help us understand the stars\u2019 life stories. Astronomers tried a variety of hypotheses about stars until they came up with the right approach to understanding their development. But the key was first making a thorough census of the stars around us.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n

This book was adapted from the following: Fraknoi, A., Morrison, D., & Wolff, S. C. (2016). Thinking Ahead In Astronomy<\/i>. OpenStax. https:\/\/openstax.org\/books\/astronomy\/pages\/18-thinking-ahead under a Creative Commons Attribution License 4.0<\/a><\/div>\r\n
Access the entire book for free at\u00a0https:\/\/openstax.org\/books\/astronomy\/pages\/1-introduction<\/a><\/div>","rendered":"
\n
\n
\n
\"Image
Figure\u00a018.1<\/strong>\u00a0Variety of Stars.\u00a0Stars come in a variety of sizes, masses, temperatures, and luminosities. This image shows part of a cluster of stars in the\u00a0Small Magellanic Cloud\u00a0(catalog number NGC 290). Located about 200,000 light-years away, NGC 290 is about 65 light-years across. Because the stars in this cluster are all at about the same distance from us, the differences in apparent brightness correspond to differences in luminosity; differences in temperature account for the differences in color. The various colors and luminosities of these stars provide clues about their life stories. (credit: modification of work by E. Olszewski (University of Arizona), European Space Agency, NASA)<\/figcaption><\/figure>\n<\/figure>\n<\/div>\n
\n
\n

Chapter Outline<\/h3>\n
18.1<\/span>\u00a0A Stellar Census<\/span><\/div>\n
18.2<\/span>\u00a0Measuring Stellar Masses<\/span><\/div>\n
18.3<\/span>\u00a0Diameters of Stars<\/span><\/div>\n
18.4<\/span>\u00a0The H\u2013R Diagram<\/span><\/div>\n<\/div>\n
\n

How do stars form? How long do they live? And how do they die? Stop and think how hard it is to answer these questions.<\/p>\n

Stars live such a long time that nothing much can be gained from staring at one for a human lifetime. To discover how stars evolve from birth to death, it was necessary to measure the characteristics of many stars (to take a celestial census, in effect) and then determine which characteristics help us understand the stars\u2019 life stories. Astronomers tried a variety of hypotheses about stars until they came up with the right approach to understanding their development. But the key was first making a thorough census of the stars around us.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

This book was adapted from the following: Fraknoi, A., Morrison, D., & Wolff, S. C. (2016). Thinking Ahead In Astronomy<\/i>. OpenStax. https:\/\/openstax.org\/books\/astronomy\/pages\/18-thinking-ahead under a Creative Commons Attribution License 4.0<\/a><\/div>\n
Access the entire book for free at\u00a0https:\/\/openstax.org\/books\/astronomy\/pages\/1-introduction<\/a><\/div>\n","protected":false},"parent":0,"menu_order":18,"template":"","meta":{"pb_part_invisible":false,"pb_part_invisible_string":""},"contributor":[],"license":[],"class_list":["post-572","part","type-part","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/parts\/572","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/parts"}],"about":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/types\/part"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/parts\/572\/revisions"}],"predecessor-version":[{"id":573,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/parts\/572\/revisions\/573"}],"wp:attachment":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/media?parent=572"}],"wp:term":[{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/contributor?post=572"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/license?post=572"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}