Question

Sirius B is a white star that has a surface temperature (in
kelvins) that is four times that of our sun. Sirius B radiates only
0.040 times the power radiated by the sun. Our sun has a radius of
6.96 × 10^{8} m. Assuming that Sirius B has the same
emissivity as the sun, find the radius of Sirius B.

Answer #1

A distant star is found to have twice the surface temperature as
our sun Tstar= 2Tsun. However, the total power emitted from that
star’s surface is found to be four times the power emitted from our
sun’s surface.
(a) how do you think we know the surface temperature of that
star without ever visiting it?(1 point)
(b) What can you tell about the radius Rstar of that star
compared to the radius Rsun of our sun?(2 points)
Rstar/Rsun=

1. The surface of the the Sun has a temperature of about 5800K.
The radius of the Sun is 6.96 x 10^8 m. Calculate the total energy
radiated by the Sun each second. Assume that the emissivity of the
SUn is 0.986
2. Equal masses of substance A at 90.1C and substance B at 14.2C
are palced in a well-insulated container of negligible mass and
allowed to come to equilibrium. If the equilibrium temperature is
78.4C, which substance has the...

a star like our un will eventually evolve into a giant red star
and then a white dwarf star. A typical white dwarf is about the
size of the earth and its surface temperature is about 2.5 x10 ^
4K. A typical red giant has a surface temperature of 3.0x10 ^ 3K
and a radius 100,000 times larger than that of a white dwarf.
What is the average radiated power per unit area and the total
power radiated by each...

A star with a radius four times that of our Sun is observed to
have a rough blackbody spectrum that peaks around 400nm. The star
illuminates a planet with the mass of the Earth at a distance of
0.7AU. This planet has a radius twice that of the Earth and absorbs
a power of 2.82*1019 W.
a) What is the planet’s albedo? The constant in Wien’s law is
2.9*10-3 m x K
b) Assuming the equilibrium temperature is approximately that...

The star Sirius has a parallax angle of 0.379 arcseconds and its
brightness is 8.8 x 10^-11 that of the Sun (b Sirius=8.8 x
10^-11bSun). The wavelength of maximum emission of Sirius is 241.7
nm.
a) What is Sirius luminosity in terms of solar luminosity?
b) And what is Sirius luminosity in Watts? (Assume that the
Sun's luminosity is 3.8 x 10^26W)
c) What is Sirius surface temperature?
d) Use the information above to compute Sirius radius.

Kepler 1606b is an exoplanet: a planet orbiting a star different
than our own. Named for the star it orbits (Kepler 1606, a star
about 3000 light-years away), it was discovered in the year 2016 by
the Kepler space telescope.
Kepler 1606b orbits its star a little bit closer than the
Earth's orbit to the Sun, at a distance of 0.64⋅?????ℎ, where
?????ℎ=1.50×1011 m is the radius of Earth's orbit. The star Kepler
1606 is bit cooler than our Sun,...

Suppose a star with the Sun’s mass and radius (the radius of the
Sun is 6.96×108 m) is rotating with a period of 25 days.
The star first blows off its outer layers and loses mass and
angular momentum before the actual collapse, thereby reducing its
radius while maintaining the same density. Then, with a mass that
is 59 % of the Sun’s mass, it collapses to a white dwarf with a
rotation period is 131 s.
A) What is...

The sun is a main sequence G5 type star with a surface
temperature TMS = 5800 K. When the sun exhausts its Hydrogen supply
it will evolve into a red giant with a surface temperature TRG =
3000 K and a radius of 100 times its present value. What is the
peak wavelength of the sun in its main sequence and red giant
phases? How many times larger will the sun’s radiative power be in
the red giant phase? Assume...

In an X-ray burster, the surface of a neutron star 10 km in
radius is heated to a temperature of 3 ×
107 K. (a) Determine the wavelength of maximum
emission of the heated surface, assuming it radiates as a
blackbody. In what part of the electromagnetic spectrum does this
lie? (b) Find the luminosity of the heated neutron star. Give your
answer in watts and in terms of the luminosity of the Sun. How does
this compare with the...

Kepler 1606b is an exoplanet: a planet orbiting a star different
than our own. Named for the star it orbits (Kepler 1606, a star
about 3000 light-years away), it was discovered in the year 2016 by
the Kepler space telescope.
Kepler 1606b orbits its star a little bit closer than the
Earth's orbit to the Sun, at a distance of 0.64⋅rearth, where
rearth=1.50×1011 m is the radius of Earth's orbit. The star Kepler
1606 is bit cooler than our Sun,...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 5 minutes ago

asked 7 minutes ago

asked 20 minutes ago

asked 23 minutes ago

asked 32 minutes ago

asked 47 minutes ago

asked 55 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago