Sunspots appear dark because they are much hotter than the surrounding gas in the photosphere.
What is the meaning of the solar constant?
the amount of energy the earth receives per unit area and unit time
What two energy transport mechanisms, in order from outside the core to the surface, is found in the Sun?
radiative diffusion, convection
As the Sun rotates, an individual sunspot can be tracked across its face. From eastern to western limb, this takes about
What natural barrier must be overcome for two protons to collide and fuse together?
In the proton-proton cycle, the helium atom and neutrino have less mass than the original hydrogen. What happens to the lost mass?
it is converted to energy (E = mc2)
(E equals the velocity of light times the mass squared.)
The solution to the solar neutrino problem which won a Nobel Prize in 2002 was
2/3 of the neutrinos decay into a new form in the 8 minutes to Earth
The stars α Cygni and β Cygni are in the constellation Cygnus. Which statement can we claim is true?
α Cygni appears brighter
What can be said with certainty about a red star and a blue star
The blue star is hotter than the red star.
In general, what can be said about type O and B stars compared to type K and M stars
They are hotter and younger
In the H-R diagram, what are the two most important (common) types of data plotted
spectral classes (and/or temperature) and absolute magnitude (and/or luminosity)
Compared to the size of the Sun, stars of all types range from approximately
0.01 to 1,000 solar radii
If we know the average separation and period of revolution for a binary system, we can then determine
the total mass of the system
What information can be gained from the light curves of eclipsing binaries
their relative sizes and period of orb
Which statement about the dark nebulae is true?
They can be penetrated only with longer wavelengths such as radio and infrared
Due to absorption of shorter wavelengths by interstellar dust clouds, distant stars behind the clouds appear
What two things are needed to create an emission nebulae
hot stars and interstellar gas, particularly hydrogen
When an electron in H changes its spin from the same to the opposite direction as the proton, it
a radio wave photon
The single most important determinant of the temperature, density, radius, luminosity, and pace of evolution of a protostar is its
How long does it take an M class star to reach the main sequence, compared to a solar type star
about twenty times longer
Which is characteristic of globular star clusters?
old age and hundreds of thousands of stars, only about 30 ly wide
The inner core of the sun where there is no nuclear fusion and no convection is
What features or structures of the sun can be seen during a total solar eclipse?
The corona and solar flares
What keeps the Sun from exploding or imploding?
Hydrostatic equilibrium between gravity and radiation
The process that we think powers the sun involves what?
The fusion of six initial protons that result in two final protons plus a helium nucleus.
What kind of a "telescope" would you build to make a neutrino detector.
A gigantic container of fluid far under the Earth's surface with some kind of
photodetectors lining the wall, all in total darkness.
For measuring distances using spectroscopic parallax, what is one of the steps in
The absolute luminosity of the star is inferred from the H-R diagram using "OBAFGKM".
In any orbiting binary star system, what can the period of the orbit and its
semimajor axis tell you?
the total mass of the binary system
What is the approximate age of a star cluster if its turn-off point is at the position of our sun on the H-R diagram?
about 10 Billion years
Open magnetic field lines (pointing out away from the Sun) in low density regions of the corona lead to
Solar wind and coronal mass ejections.
Going out from the center from the Sun, in sequence we have
the core, radiation zone, convection zone, photosphere, chromosphere, corona.
If a one kilogram melon were to be completely turned into energy, how much energy would it produce
9 x 1016 joules E=mc2 = 1kg*(3 x 108 m/s )2 = 9 x 1016 J.
The solar neutrino problem refers to what
The observation that only about 1/3 of the expected neutrino flux from the sun was initially observed, for instance by Davis
The star Altair has a parallax of 0.20 seconds of arc. How far away is it?
5 parsecs d = 1/p = 1/0.2 = 5 parsecs
We see the apparent magnitude of a star from its observed brightness. How is the absolute magnitude of a star defined?
It is the apparent magnitude it would have it were 10 parsecs from us.
Name two main regions where stars appear away from the main sequence in the H-R diagram:
The white dwarf and red giant regions.
If spectroscopic luminosity classification gives us an estimated distance to the faint star SAO 47552 of about 3300 light years, then its parallax would be only
If a 100 kg zombie were to suddenly be completely turned into energy, how much
energy would it produce?
e) 9 x 1018 joules. E = mc2 = 100(3x108)2 = 1009x1016 = 9x1018.
The star Botox 959A has a parallax of 0.01 arc seconds. How far away is it from
100 parsecs. d = 1/p = 1/0.01 = 100
Assume that the relationship between the lifetime of a star (in solar lifetimes) is
proportional to the inverse of the mass of a star (in solar masses) cubed, that is:
Eight solar lifetimes. Lifetime = 1/(1/2)3 = 1/(1/8) = 8.
If spectroscopic luminosity classification gives us an estimated distance to the faint star SAO 47552 of about 3300 light years, then its parallax would be about
0.001 arcseconds (note that 3300 LY = 1000 pc, so 1/1000 = 0.001)
If a two metric ton (2000 kg) car were to be completely turned into energy, how much energy would it produce?
1.8 x 1020 Joules
The speed of light is 3.00 × 108 m/s. If 2.00 kg of mass is converted to energy, how much energy will be produced
a) 1.80 × 1017 J
Two stars both have parallaxes of 0.023 arseconds, but star A has apparent magnitude 2.3, while star B has apparent magnitude 7.3. Which statement is true?
one magnitude unit corresponds to a change of 2.5 in brightness. So, a difference of 5 in magnitude corresponds to a difference of 100 in brightness, i.e. 18.104.22.168.52.5 ~ 100
Assume that the relationship between the lifetime of a star (in solar lifetimes) is proportional to the inverse of the mass of a star (in solar masses) cubed, that is:
Lifetime = 1/Mass3. So, if a star has a mass that is ten times that of our Sun, how long does it live?
One thousandth of a solar lifetime.