Horizons: Exploring the Universe (MindTap Course List)
14th Edition
ISBN: 9781305960961
Author: Michael A. Seeds, Dana Backman
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 9, Problem 13P
To determine
What is its radius if a T Tauri star is the same temperature as the Sun but is ten timesmore luminous?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
If a T Tauri star is the same temperature as the Sun but is eighteen times more luminous, what is its radius relative to the Sun? (Hint: Use the luminosity-radius-temperature relation:
L
L
=
R
R
2
T
T
4
.)
R
R
=
The origin of the above quote (with "flame" or "candle" sometimes substituted for "light") is unclear. It is often attributed to either Lao Tzu or to the character Eldon Tyrell from the 1982 movie Blade Runner.
Stars follow a similar law, although the factor isn't precisely 1/2. In this problem, you will figure out the precise factor that the quote should have to apply to stars.
Using the proportionality relationships for stellar luminosity as a function of mass and stellar lifetime as a function of mass, combine the two equations to arrive at a proportionality for stellar lifetime as a function of luminosity.
Consider a star with luminosity twice that of the Sun's. Compute the star's main sequence lifetime as a multiple of the Sun's main sequence lifetime. Enter your result below as a decimal. For example, if you found TT⊙=0.3, enter "0.3". (Here T is the star's lifetime and T⊙ is the Sun's main sequence lifetime.
Using solar units, we find that a star has 4 times the luminosity of the Sun, a mass 1.25 times the mass of the Sun, and a surface temperature of 4090 K (take the Sun's surface temperature to be 5784 K for the sake of this problem). This means the star has a radius of.................... solar radii and is a .................... star (use the classification).
Chapter 9 Solutions
Horizons: Exploring the Universe (MindTap Course List)
Ch. 9 - Prob. 1RQCh. 9 - Why evidence can you cite that the interstellar...Ch. 9 - Prob. 3RQCh. 9 - Prob. 4RQCh. 9 - Prob. 5RQCh. 9 - Prob. 6RQCh. 9 - Prob. 7RQCh. 9 - Prob. 8RQCh. 9 - Prob. 9RQCh. 9 - Prob. 10RQ
Ch. 9 - Prob. 11RQCh. 9 - Prob. 12RQCh. 9 - How does the CNO cycle differ from the...Ch. 9 - Prob. 14RQCh. 9 - Step-by-step, explain how energy flows from the...Ch. 9 - Prob. 16RQCh. 9 - Prob. 17RQCh. 9 - Prob. 18RQCh. 9 - Prob. 19RQCh. 9 - Prob. 20RQCh. 9 - Prob. 1DQCh. 9 - What is your favorite home-cooked meal? In terms...Ch. 9 - Prob. 3DQCh. 9 - How does hydrostatic equilibrium relate to hot-air...Ch. 9 - Prob. 1PCh. 9 - Prob. 2PCh. 9 - Prob. 3PCh. 9 - Prob. 4PCh. 9 - Prob. 5PCh. 9 - Prob. 6PCh. 9 - Prob. 7PCh. 9 - Prob. 8PCh. 9 - Prob. 9PCh. 9 - Prob. 10PCh. 9 - If a protostellar disk is 200 AU in radius and the...Ch. 9 - Prob. 12PCh. 9 - Prob. 13PCh. 9 - Prob. 14PCh. 9 - H much energy is produced when the CNO cycle...Ch. 9 - Prob. 16PCh. 9 - Prob. 1LTLCh. 9 - Prob. 2LTL
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
- Table 17.2 lists the temperature ranges that correspond to the different spectral types. What part of the star do these temperatures refer to? Why?arrow_forwardWhat elements are stars mostly made of? How do we know this?arrow_forwardHow do stars typically “move” through the main sequence band on an HR diagram? Why?arrow_forward
- Which of the following can you determine about a star without knowing its distance, and which can you not determine: radial velocity, temperature, apparent brightness, or luminosity? Explain.arrow_forwardAt the average density of the interstellar medium, 1 atom per cm3, how big a volume of material must be used to make a star with the mass of the Sun? What is the radius of a sphere this size? Express your answer in light-years.arrow_forwardIf you were to compare three stars with the same surface temperature, with one star being a giant, another a supergiant, and the third a main-sequence star, how would their radii compare to one another?arrow_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_forwardIf a 100 solar mass star were to have a luminosity of 107 times the Sun’s luminosity, how would such a star’s density compare when it is on the main sequence as an O-type star, and when it is a cool supergiant (M-type)? Use values of temperature from Figure 18.14 or Figure 18.15 and the relationship between luminosity, radius, and temperature as given in Exercise 18.47. Figure 18.15 Schematic HR Diagram for Many Stars. Ninety percent of all stars on such a diagram fall along a narrow band called the main sequence. A minority of stars are found in the upper right; they are both cool (and hence red) and bright, and must be giants. Some stars fall in the lower left of the diagram; they are both hot and dim, and must be white dwarfs. Figure 18.14 HR Diagram for a Selected Sample of Stars. In such diagrams, luminosity is plotted along the vertical axis. Along the horizontal axis, we can plot either temperature or spectral type (also sometimes called spectral class). Several of the brightest stars are identified by name. Most stars fall on the main sequence.arrow_forward
- If a star has a surface temperature of 3000 K but a luminosity 150 times greater than our Sun, what size is this star? Give your answer in units of the solar radius, R.arrow_forwardAn O8 V star has an apparent visual magnitude of +5. Use the method of spectroscopic parallax to estimate the distance to the star (in pc). (Hints: Refer to one of the H–R diagrams in the chapter, and use the magnitude–distance formula, d = 10(mV − MV + 5)/5 where d is the distance in parsecs, mV and MV are the apparent and absolute visual magnitude respectively.)arrow_forwardIf a T Tauri star is the same temperature as the Sun but is seventeen times more luminous, what is its radius relative to the Sun? (Hint: Use the luminosity-radius-temperature relation:L/L=(R/R)^2(T/T)^4)arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Foundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage LearningStars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage LearningAstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStax
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax