The luminosity of a star with a radius of (7.20x10^6) meters and a surface temperature of 30,000 Kelvin is ______ Watts
The luminosity of a star with a radius of (7.20x10^6) meters and a surface temperature of...
The brightest star in the northern celestial hemisphere has a surface temperature of about 4300 K and it is 170 times more luminous than the Sun. Calculate the radius of the star in units of the radius of the solar radius (round the result to the nearest integer) In the calculation, you may assume that the Sun has a radius of 7E8 meters and a luminosity of 3.8E26 watts.
Stellar RadiiThe red supergiant (RSG) star Betelgeuse has a luminosity of 120,000L, and a surface temperature ofaboutTeff= 3650 K. What is its’ radius (in both metres and astronomical units)?
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.
Star A has radius R, a temperature of T degrees Kelvin, and is at a distance D from Earth. Star B has radius 2R, a temperature 3T and is at a distance 4D from Earth. Star A has an apparent brightness of P watts per square meter. What is the apparent brightness of star B as a multiple of P?
A neutron star has a radius of 10 km, and a temperature of 1 million K. What is its luminosity?
[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?
The bright star Rigel in the constellation Orion has a surface temperature about 1.6 times that of the Sun. Its luminosity is about 64,000 times that of the Sun. What is Rigel's radius compared to the radius of the Sun (in units of solar radii, Rø)?
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.
= A1. A distant star is determined to have a surface temperature of Tstar - 6000K and a radius of 5.0 x 108 m. A planet named Hydra is detected orbiting this star at a distance of 1.0 x 1011 m and has an albedo of 0.60. [1] (a) At what wavelength is the peak irradiance from this star? [1] (b) What is the total Luminosity of the star? (c) What is the effective temperature of Hydra? (d) The actual...
Part A. What would be the luminosity of the Sun if its surface temperature were 3900 K and its radius were 1.5 AU ? Part B. What would be the luminosity of the Sun if its surface temperature were 3900 K and its radius were 7.0 AU ? *I don't understand how to calculate this out. Instructor didn't really cover this.