21st Century Astronomy
6th Edition
ISBN: 9780393428063
Author: Kay
Publisher: NORTON
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 13, Problem 17QP
To determine
Whether it is a requisite to know the star’s distance to determine its given set of properties
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
12.
A star with spectral type MO has a surface temperature of 3750 K and a radius of 0.63 Rsun: How many
times more luminous is this star than the Sun? (if it is less luminous enter a number less than one)
Answer:
Submit All Answers Last Answer: 0.0923
Incorrect, tries 1/5.
Hint: Use the Luminosity equation, which says that L is proportional to R^2 T^4. If you keep these as
ratios compared to the sun, your L will also come out as a ratio compared to the Sun.
This star has a mass of 0.4 Msun- Using the simple approximation that we made in class, what is the
main sequence lifetime of this star? You may assume that the lifetime of the sun is 1010 yr.
Answer:
Submit All Answers
Compare this to the lifetime of a MO star listed in Table 22.1 (computed using a more sophisticated
approach). Is the value you calculated in the previous problem longer or shorter than what is reported
in the table? (L for longer, S for shorter) (You only get one try at this problem.)
Answer:
Submit All Answers
"51 Pegasi" is the name of the first normal star (besides the Sun) around which a planet was discovered. It is in the constellation Pegasus the horse. Its parallax is measured to be 0.064 arcsec.
a. What is its distance from us?
b. The apparent brightness is 1.79 × 10-10 J/(s·m2 ). What is the luminosity? How does that compare with that of the Sun? Look up the temperature: how do
Choose the correct statements concerning spectral classes of stars. (Give ALL correct answers, i.e., B, AC, BCD...)
A) Neutral hydrogen lines dominate the spectrum for stars with temperatures around 10,000 K because a lot of the hydrogen is in the n=2 level.
B) Hydrogen lines are weak in type O-stars because most of it is completely ionized.
C) Oh Be A Fine Guy/Girl Kiss Me, is a mnemonic for remembering spectral classes.
D) The spectral sequence has recently been expanded to include L, T, and Y classes.
E) K-stars are dominated by lines from ionized helium because they are so hot.
F) The spectral types of stars arise primarily as a result of differences in temperature.
Chapter 13 Solutions
21st Century Astronomy
Ch. 13.1 - Prob. 13.1CYUCh. 13.2 - Prob. 13.2CYUCh. 13.3 - Prob. 13.3CYUCh. 13.4 - Prob. 13.4CYUCh. 13 - Prob. 1QPCh. 13 - Prob. 2QPCh. 13 - Prob. 3QPCh. 13 - Prob. 4QPCh. 13 - Prob. 5QPCh. 13 - Prob. 6QP
Ch. 13 - Prob. 7QPCh. 13 - Prob. 8QPCh. 13 - Prob. 9QPCh. 13 - Prob. 10QPCh. 13 - Prob. 11QPCh. 13 - Prob. 12QPCh. 13 - Prob. 13QPCh. 13 - Prob. 14QPCh. 13 - Prob. 15QPCh. 13 - Prob. 16QPCh. 13 - Prob. 17QPCh. 13 - Prob. 18QPCh. 13 - Prob. 19QPCh. 13 - Prob. 20QPCh. 13 - Prob. 21QPCh. 13 - Prob. 22QPCh. 13 - Prob. 23QPCh. 13 - Prob. 24QPCh. 13 - Prob. 25QPCh. 13 - Prob. 26QPCh. 13 - Prob. 27QPCh. 13 - Prob. 28QPCh. 13 - Prob. 29QPCh. 13 - Prob. 30QPCh. 13 - Prob. 31QPCh. 13 - Prob. 32QPCh. 13 - Prob. 33QPCh. 13 - Prob. 34QPCh. 13 - Prob. 35QPCh. 13 - Prob. 36QPCh. 13 - Prob. 37QPCh. 13 - Prob. 38QPCh. 13 - Prob. 39QPCh. 13 - Prob. 40QPCh. 13 - Prob. 41QPCh. 13 - Prob. 42QPCh. 13 - Prob. 43QPCh. 13 - Prob. 44QPCh. 13 - 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
- The spectral type of a star is directly related to its color. Recall that a star emits light as a blackbody, which has a particular shape to its spectrum, as shown in this figure. Based on this, what basic property of a star determines its color (and thus its spectral type)? Choose one: A. age B. composition C. radius D. temperaturearrow_forward. The spectrum of Star A peaks at 700 nm. The spectrum of Star B peaks at 470 nm. We know nothing about what stage of stellar evolution either of these stars are in. Which of the following are true? A. Star A has a higher luminosity than Star B. B. Star B has a higher luminosity than Star A. C. Star A is cooler than Star B. D. Not enough information to comment on their luminosities. E. B and C F. C and Darrow_forwardQ10: If you know that the difference of the apparent magnitude between two stars is equal to 5 magnitudes. What is their brightness? Use this equation Am BB -2.5 log10 () = mb - ma = BA Q11. If the apparent magnitude of the first star in a binary star system is equal 1m and the apparent magnitude of the second star is equal 2m. Calculate the apparent magnitude of the system. Q12. Calculate the distance of a star if you know that its absolute magnitude is equal to (2m) and its apparent magnitude (-2m).arrow_forward
- 1:Which star has been redshifted the most? 2:Which star is moving towards us the fastest? Star C Star D Star A Star B 3:The wavelength of this spectral feature is measured to be 600nm in the lab, and 609 in Star A. What is the radial velocity of Star A? using km/s,arrow_forwardSuppose a star has a luminosity of 7.0x1026 watts and an apparent brightness of 4.0x10-12 watt/m?. How far away is it? Give your answer in both kilometers and light-years.arrow_forwardEach choice below lists a spectral type and luminosity class for a star. Which one is a hot main sequence star? OA. spectral type 09, luminosity class I O B. spectral type 01, luminosity class V O C. spectral type M2, luminosity class I OD. spectral type M2, luminosity class Varrow_forward
- Q9. If the luminosity of star B is 25 times the luminosity of star A, then find the distance of star A if you know that the two stars have the same brightness, and that star B is 10 astronomical leagues away from us. Use the relationship: BB V BA da dg Q10: If you know that the difference of the apparent magnitude between two stars is equal to 5 magnitudes. What is their brightness? Use this equation Am т 3D ть — т, — —2.5 logio Q11. If the apparent magnitude of the first star in a binary star system is equal 1m and the apparent magnitude of the second star is equal 2m. Calculate the apparent magnitude of the system. Q12. Calculate the distance of a star if you know that its absolute magnitude is equal to (2m) and its apparent magnitude (-2m).arrow_forwardWhich of the following WOULD NOT characterizes the type(s) of star we would find at g, m, n, o, and p on the Hertzsprung-Russel Diagram (Figure 4) a. are all smaller than q,i,h. b. fuse hydrogen into helium. c. are called, “the main sequence”. d. fuse He into heavier elements. e. get smaller towards the right sidearrow_forwardLet’s say you’re looking for extrasolar planets. You observe a star that has a spectral shift in the line that is supposed to be at at 656.28011 nm – this star shows this line at 656.28005 nm. What is the radial velocity of star (in m/s) and in what direction in relation to you? a) 27.4 m/s, towards b) 27.4 km/s, away c) -27.4 m/s, toward d) -27.4 km/s, awayarrow_forward
- Distance from Apparent Brightness (rank; brightest, 8 = dimmest) Name of Star Earth (light years) | 1 = Sun Sirius 8.6 Canopus Arcturus 309 3. 36.7 4 Rigel Vega Alpha Centauri Bernard's Star 773 5 25.3 4.3 7 5.9 8 13 What sentence explains why a star can be much farther from Earth than the Sun, but still be bright? nida nenv A. Distance from Earth and apparent brightness are related. B. Bright stars that are farther away are larger than the Sun. C. The higher it appears in the sky, the brighter the star. D. The apparent brightness scale goes up as stars get dimmer. del sdTarrow_forwardStellar Classification and H-R Diagram Placement (40 points available). a. Where is your star located on the H-R diagram (luminosity class/region of the diagram, spectral class, luminosity/brightness)? How does this compare to that of The sun ? Discuss the inferences of the specific placement and stellar classification of your star with respect to mass, size/radius, color/temperature, composition? c. Discuss how this placement on the diagram relates to the star’s observed stage of evolution, previous evolution, and expected future evolutionary path. How does this compare to that of the Sun? d. What is the estimated total lifespan of your star and what is the estimated age of your star right now? How does this compare to that of the Sun? All of them is about Lutyen star .arrow_forwardA star has a measured radial velocity of 300 km/s. If you measure the wavelength of a particular spectral line of Hydrogen as 657.18 nm, what was the laboratory wavelength (in nm) of the line? (Round your answer to at least one decimal place.) nm Which spectral line does this likely correspond to? Balmer-alpha (656.3 nm) Balmer-beta (486.1 nm) Balmer-gamma (434.0 nm) Balmer-del ta (410.2 nm)arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios