21st Century Astronomy
6th Edition
ISBN: 9780393428063
Author: Kay
Publisher: NORTON
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 17, Problem 27QP
To determine
The way in which astronomers can estimate the age of a star cluster by taking a looking at its H-R diagram.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
How is the turnoff point on the H-R diagram of a cluster related to the cluster’s age?
If an open cluster contains 500 stars and is 25 pc in diameter, what is the average distance between the stars?
If an open cluster contains 650 stars and is 27 pc in diameter, what is the average distance between the stars? (Hint: On average, what share of the volume of the cluster surrounds each star?)
Chapter 17 Solutions
21st Century Astronomy
Ch. 17.1 - Prob. 17.1CYUCh. 17.2 - Prob. 17.2CYUCh. 17.3 - Prob. 17.3CYUCh. 17.4 - Prob. 17.4CYUCh. 17 - Prob. 1QPCh. 17 - Prob. 2QPCh. 17 - Prob. 3QPCh. 17 - Prob. 4QPCh. 17 - Prob. 5QPCh. 17 - Prob. 6QP
Ch. 17 - Prob. 7QPCh. 17 - Prob. 8QPCh. 17 - Prob. 9QPCh. 17 - Prob. 10QPCh. 17 - Prob. 11QPCh. 17 - Prob. 12QPCh. 17 - Prob. 13QPCh. 17 - Prob. 14QPCh. 17 - Prob. 15QPCh. 17 - Prob. 16QPCh. 17 - Prob. 17QPCh. 17 - Prob. 18QPCh. 17 - Prob. 19QPCh. 17 - Prob. 20QPCh. 17 - Prob. 21QPCh. 17 - Prob. 22QPCh. 17 - Prob. 23QPCh. 17 - Prob. 24QPCh. 17 - Prob. 25QPCh. 17 - Prob. 26QPCh. 17 - Prob. 27QPCh. 17 - Prob. 28QPCh. 17 - Prob. 29QPCh. 17 - Prob. 30QPCh. 17 - Prob. 31QPCh. 17 - Prob. 32QPCh. 17 - Prob. 33QPCh. 17 - Prob. 34QPCh. 17 - Prob. 35QPCh. 17 - Prob. 36QPCh. 17 - Prob. 37QPCh. 17 - Prob. 38QPCh. 17 - Prob. 39QPCh. 17 - Prob. 40QPCh. 17 - Prob. 41QPCh. 17 - Prob. 42QPCh. 17 - Prob. 43QPCh. 17 - Prob. 44QPCh. 17 - Prob. 45QP
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- If the Sun were a member of the cluster NGC 2264, would it be on the main sequence yet? Why or why not?arrow_forwardConsider the following five kinds of objects: open cluster, giant molecular cloud, globular cluster, group of O and B stars, and planetary nebulae. A. Which occur only in spiral arms? B. Which occur only in the parts of the Galaxy other than the spiral arms? C. Which are thought to be very young? D. Which are thought to be very old? E. Which have the hottest stars?arrow_forwardSuppose a star cluster were at such a large distance that it appeared as an unresolved spot of light through the telescope. What would you expect the overall color of the spot to be if it were the image of the cluster immediately after it was formed? How would the color differ after 1010 years? Why?arrow_forward
- If you assume that a globular cluster 6 arc minutes in diameter is actually 27 pc in diameter, how far away is it? (Hint: Use the small-angle formula.)arrow_forwardIf a globular cluster contains 2 million stars and is 30 pc in diameter, what is the average distance between the stars?arrow_forwardYou can use the equation in Exercise 22.34 to estimate the approximate ages of the clusters in Figure 22.10, Figure 22.12, and Figure 22.13. Use the information in the figures to determine the luminosity of the most massive star still on the main sequence. Now use the data in Table 18.3 to estimate the mass of this star. Then calculate the age of the cluster. This method is similar to the procedure used by astronomers to obtain the ages of clusters, except that they use actual data and model calculations rather than simply making estimates from a drawing. How do your ages compare with the ages in the text? Figure 22.10 NGC 2264 HR Diagram. Compare this HR diagram to that in Figure 22.8; although the points scatter a bit more here, the theoretical and observational diagrams are remarkably, and satisfyingly, similar. Figure 22.12 Cluster M41. (a) Cluster M41 is older than NGC 2264 (see Figure 22.10) and contains several red giants. Some of its more massive stars are no longer close to the zero-age main sequence (red line). (b) This ground-based photograph shows the open cluster M41. Note that it contains several orange-color stars. These are stars that have exhausted hydrogen in their centers, and have swelled up to become red giants. (credit b: modification of work by NOAO/AURA/NSF) Figure 22.13 HR Diagram for an Older Cluster. We see the HR diagram for a hypothetical older cluster at an age of 4.24 billion years. Note that most of the stars on the upper part of the main sequence have turned off toward the red-giant region. And the most massive stars in the cluster have already died and are no longer on the diagram. Characteristics of Main-Sequence Starsarrow_forward
- H II regions can exist only if there is a nearby star hot enough to ionize hydrogen. Hydrogen is ionized only by radiation with wavelengths shorter than 91.2 nm. What is the temperature of a star that emits its maximum energy at 91.2 nm? (Use Wien’s law from Radiation and Spectra.) Based on this result, what are the spectral types of those stars likely to provide enough energy to produce H II regions?arrow_forwardAccording to the text, a star must be hotter than about 25,000 K to produce an H II region. Both the hottest white dwarfs and main-sequence O stars have temperatures hotter than 25,000 K. Which type of star can ionize more hydrogen? Why?arrow_forwardIn the HR diagrams for some young clusters, stars of both very low and very high luminosity are off to the right of the main sequence, whereas those of intermediate luminosity are on the main sequence. Can you offer an explanation for that? Sketch an HR diagram for such a cluster.arrow_forward
arrow_back_ios
arrow_forward_ios
Recommended textbooks for you
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxStars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage LearningFoundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
- Stars and GalaxiesPhysicsISBN:9781305120785Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies
Physics
ISBN:9781305120785
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning