What star is 20 pc from Earth, has a luminosity of 160 times that of the Sun, a surface temperature of 4000 K, and has an absolute magnitude of -0.066? How would I figure this out?
What star is 20 pc from Earth, has a luminosity of 160 times that of the...
Betelgeuse, a bright red star in the constellation Orion, has a luminosity that is 100,000 times that of the Sun However, the surface temperature of Betelgeuse is only 3000 K. Assuming that the emissivity of stars is 1, find the radius of Betelgeuse.
37. Jupiter at its present location, were a star? What would Earth be like ? Assume this hypothetical Jupiter with 75 × MJ would be a red dwarf with the same density as the Sun but a surface temperature of only 2500 K. What would be its total luminosity, compared to that of the Sun? (Hint: recall that to be a star, Jupiter would have to be 75 times more mass than it has today.)
A red giant star has a temperature of 4500 K and a luminosity of 10700 LSun. How many times bigger is this star than the Sun?
A star of apparent magnitude 13.0 lies 600 pc from Earth. If interstellar absorption results in an average extinction of 2.0 mag/kpc, calculate the star's absolute magnitude and luminosity Express your answer using two significant figures. IVO AEO ? M=
ity of the 20 Mo star Sirius predicted by the mass-luminosity equation (Unit 58). Its observed luminosity is about 20 LO How can you explain the difference? The mass-luminosity relationship predicts that Sirius is about Sirius's higher luminosity is a result of its higher Sun's. Themassluninosit reSisis a times more luminous than the Sun. surface temperature and lrger surface area compared to the
[4] For the previous planet and star (with a luminosity = 0.041 solar luminosity), assuming a circular orbit, what would be the distance from the star such that the planet's surface temperature is 280 K (no atmosphere or greenhouse effect to worry about)? What are the orbital period and circular velocity of the planet? What is the circular velocity of the star (in m/s) that would be measured with the Doppler shift?
Planet X has 20 times the mass of the earth and 3 times the earth's radius. It orbits star Y at a distance of 8 AU, where 1 AU is the earth-sun distance. Star Y has twice the mass of our sun. (a) What is the orbital period of Planet X in years? (b) An astronaut has an earth weight of 120 lbs. What is her weight on the surface of planet X?
6. The bright star Arcturus in the constellation Boötes has a surface temperature about 0.74 times that of the Sun. Its luminosity is about 170 times that of the Sun. (a) What is Arcturus’ radius compared to the radius of the Sun (in units of solar radii, ?⊙)? (b) What type of star is Arcturus (a dwarf, a giant, or a supergiant)? Explain your reasoning.
Question 16 (1 point) Visible light has wavelengths ranging between approximately 4000 and 7000 Angstroms (400 to 700 nanometres). Which of the following statements is true regarding the surface temperature of a star for which the wavelength of maximum intensity falls in the visible range t could never be cooler than 8000 K It must always be cooler than 5500 K t must lie between 8000 K and 5500 K It must always be hotter than 3500 K Question 17...
A neutron star has a radius of 10 km, and a temperature of 1 million K. What is its luminosity?