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This lecture discusses the correlation between luminosity (L) and temperature (T) in the nearest stars, as shown in the Hertzsprung-Russell (H-R) Diagram. It also explores the concept of age in stars and how their structure changes over time. The lecture includes examples from open clusters like NGC 290 and the Pleiades, as well as globular clusters M10 and M55. Pre-main-sequence and post-main-sequence evolutionary tracks are also analyzed. Additionally, the presence of dust in spiral galaxies and a dark nebula in our galaxy is discussed.
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ASTR 1102-0022008 Fall Semester Joel E. Tohline, Alumni Professor Office: 247 Nicholson Hall [Slides from Lecture11]
Plot “L vs. T” for 27 Nearest Stars Data drawn from Appendix 4 of the textbook.
L and T appear to be Correlated Nearest Stars
L and T appear to be Correlated A few of the brightest stars in the night sky
Apply the “Age” Concept to Other Stars • How long can other stars live? • tage = fMc2/L • (tage /1010 years) = (M/Msun)/(L/Lsun)
Pleiades Star Cluster(age approximately 50 million years) Figure 18-19
Post-main-sequence Evolutionary Tracks: Figure 19-9
H-R Diagram for Open Clusters Figure 19-14
Globular Cluster M10 Figure 19-12
Globular Cluster M10 Figure 19-12
Dust in Spiral Galaxies Figure 18-8
A Dark Nebula in Our Galaxy Figure 18-4
Pre-main-sequence Evolutionary Tracks: Figure 18-10
NGC 2264: A Very Young Cluster Figure 18-18