AST 1002
Test 3, Spring 2006
QQ 1 At present the Sun's energy comes from 
AA S 1 (1) fusion of hydrogen nuclei to form helium 
(2) conversion of gravitational potential energy into heat 
and radiation
(3) combustion of hydrogen and oxygen to form water
(4) NVA
(5) NVA

QQ 2 Hydrostatic equilibrium is the balance between 
AA S 1 (1) the inward pull of gravity and the outward push of 
pressure difference
(2) the inward pull of magnetic force and the outward push 
of pressure difference
(3) the inward pull of gravity and the outward push of 
centrifugal "force"
(4) NVA
(5) NVA

QQ 3 Energy transport from the Sun's core where it's 
produced to its photosphere is by 
AAS 1 (1) radiation in the inner part and convection in the 
outer part
(2) convection in the inner part and radiation in the outer 
part
(3) conduction throughout the interior
(4) NVA
(5) NVA

QQ 4 Sunspots are found in which part of the Sun's 
atmosphere?
AA S 1 (1) photosphere
(2) chromosphere
(3) corona
(4) NVA
(5) NVA


QQ 5 Sunspots are darker than their surroundings because 
AA S 1 (1) they are cooled by their strong magnetic fields
(2) they are higher in the Sun's atmosphere than the surrounding 
gas and thus are cooler
(3) they are gaps in the Sun's atmosphere where we can "see" 
to denser (and thus darker) material below
(4) NVA
(5) NVA

QQ 6 The Sun's overall magnetic field is thought to be 
produced by 
AA S 1 (1) the Babcock mechanism
(2) the Zeeman effect
(3) solar flares 
(4) NVA
(5) NVA

QQ 7 The neutrino problem for the Sun, which indicated for some 
time that the computer models of the Sun were wrong, was 
basically that 
AA S 1 (1) the Sun wasn't producing as many neutrinos as were 
predicted based on the models
(2) the Sun was producing way more neutrinos than the models 
predicted it should
(3) the Sun was producing neutrinos, which it shouldn't be 
doing at all if the models were right
(4) NVA
(5) NVA

QQ 8 Which of the following is a basic property of stars?
AA S 1 (1) luminosity
(2) apparent magnitude
(3) spectral type
(4) NVA
(5) NVA

QQ 9 Which of the following cannot be used (at least in 
principle) to find a star's radius?
AA S 1 (1) visual binary system of known distance
(2) interferometer applied to a star of known distance
(3) eclipsing and double-line spectroscopic binary system
(4) NVA
(5) NVA

QQ 10 The Harvard spectral classification in order of 
increasing surface temperature going from left to 
right is
AA S 1 (1) MKGFABO
(2) OBAFGKM
(3) ABFGKMO
(4) NVA
(5) NVA

QQ 11 Which MK luminosity class applies to main sequence 
stars?
AA S 1 (1) V   (2) I   (3) X    (4) NVA   (5) NVA

QQ 12 The method of estimating a star's distance based on its 
shift on the sky as the Earth orbits the sun is termed 
AA S 1 (1) trigonometric parallax
(2) spectroscopic parallax
(3) period-luminosity relation
(4) NVA
(5) NVA

QQ 13 Which main sequence star will have the longest 
lifetime?
AA S 1 (1) a 0.1 solar mass star
(2) a 1 solar mass star
(3) a 60 solar mass star
(4) NVA
(5) NVA

QQ 14 In the Hertzsprung-Russell (H-R) diagram, the 
largest stars are in the 
AA S 1 (1) red giant region, at upper right
(2) red giant region, at upper left
(3) white dwarf region, at lower left 
(4) NVA
(5) NVA

QQ 15 Open or galactic clusters are the ones found 
in the sky 
AA S 1 (1) near the Milky Way band of light
(2) all over the sky except near the Milky Way, 
which they mostly avoid
(3) tightly packed around the direction to the 
galactic center
(4) NVA
(5) NVA

QQ 16 A young open or galactic cluster will have a 
main sequence turnoff point 
AA S 1 (1) near the upper end of where the main 
sequence can be 
(2) near the bottom of the main sequence
(3) somewhere near the middle of the main 
sequence, where the Sun would be
(4) NVA
(5) NVA

QQ 17 Star formation occurs in molecular clouds 
because they are the places where the physical 
conditions are favorable for the gas to be 
gravitationally unstable, with 
AA S  1 (1) high density and low temperature
(2) low density and low temperature
(3) high density and high temperature
(4) NVA
(5) NVA
 
QQ 18 The lower limit on the mass of a main 
sequence star is set by 
AA S 1 (1) the dominance of electron degeneracy pressure
(2) the dominance of radiation pressure
(3) the strength of the star's magnetic field
(4) NVA
(5) NV

QQ 19 Which kind of pressure depends only on temperature 
and not on density?
AA S 1 (1) radiation pressure
(2) electron degeneracy pressure
(3) gas pressure
(4) NVA
(5) NVA

QQ 20 Approximately what temperature is needed as a 
minimum for the triple-alpha process?
AAS 1 (1) 100,000,000 K.
(2) 10,000,000 K.
(3) 1,000,000 K.
(4) NVA
(5) NVA

QQ 21 The last evolutionary stage of a low-mass star 
before its end stage is the 
AA S 1 (1) red giant stage
(2) horizontal branch stage
(3) asymptotic giant branch stage 
(4) NVA
(5) NVA

QQ 22 The evolutionary stage during which a star 
like the Sun will produce a planetary nebula is 
the 
AA S 1 (1) asymptotic giant branch stage
(2) main sequence stage
(3) red giant branch stage
(4) NVA
(5) NVA

QQ 23 The term "nuclear exhaustion" refers to 
AA S 1 (1) a star's ending up with an inert iron core
(2) a nuclear "burning" shell inside a star reaching 
the low density outer regions where it shuts down
(3) a star's converting all the hydrogen in its core 
to helium
(4) NVA
(5) NVA

QQ 24 The Algol paradox is when the more highly evolved star 
in a close binary system has less mass than its companion.  
The explanation is that 
AA S 1 (1) the star that was originally more massive and which 
evolved faster initially has transferred mass to its companion
(2) the stars formed separately and the less massive one is 
much older than its companion
(3) proximity by itself causes the stars to age at differing rates
(4) NVA
(5) NVA

QQ 25 Neutron stars are supported against their own gravity by 
which kind of pressure?
AA S 1 (1) neutron degeneracy pressure
(2) electron degeneracy pressure
(3) radiation pressure
(4) NVA
(5) NVA

QQ 26 A Type Ia or white dwarf supernova occurs when a white 
dwarf 
AA S 1 (1) in a binary system gains mass and goes over the 
Chandrasekhar limit, causing it to collapse 
(2) in a binary system accretes mass and gets hot enough for 
hydrogen fusion to ignite 
(3) reaches nuclear exhaustion, being composed of iron
(4) NVA
(5) NVA

QQ 27 Pulsars are 
AA S 1 (1) rotating magnetic neutron stars
(2) pulsating white dwarfs
(3) rotating white dwarfs
(4) NVA
(5) NVA

QQ 28 The Schwarzschild radius of a black hole is defined 
as the radius of the event horizon, in other words,  
AA S 1 (1) the minimum distance from the center of the 
black hole where events can be seen from outside
(2) the minimum distance an object can approach a black hole 
without being pulled in
(3) the maximum distance at which an event can be observed 
by an observer at the center of the black hole
(4) NVA
(5) NVA

QQ 29 Which of the following is found in the halo of the 
Milky Way?
AA S 1 (1) globular cluster
(2) O star 
(3) the Sun
(4) NVA
(5) NVA

QQ 30 The orbits of stars in the disk are 
AA S 1 (1) approximately circular and almost all in the 
same direction (galactic rotation)
(2) highly eccentric but almost all in the same direction 
(galactic rotation)
(3) highly eccentric and randomly oriented, with roughly 
the same number in one direction of rotation as the other
(4) NVA
(5) NVA

QQ 31 Population II stars are in general
AA S 1 (1) old and metal-poor
(2) old and metal-rich
(3) a mix of various ages young and old and metal-rich
(4) NVA
(5) NVA

QQ 32 The rotation curve of the Milky Way is 
AA S 1 (1) mainly flat, indicating the presence of mass that 
is in addition to the stars and gas we see (dark matter)
(2) linear, like that of a merry-go-round, indicating a 
uniform mass density
(3) Keplerian, like the Solar System, indicating the mass is 
effectively concentrated at the center
(4) NVA
(5) NVA

QQ 33 Which type of galaxy has relatively little gas and 
dust and almost entirely old stars?
AA S 1 (1) elliptical
(2) spiral
(3) irregular -- the amorphous type, not peculiar
(4) NVA
(5) NVA

QQ 34 The fact that the spiral nebulae are star systems 
like our own Milky Way was established by 
AA S 1 (1) Hubble
(2) Baade
(3) Shapley
(4) NVA
(5) NVA

QQ 35 The Universe is presently expanding 
AA S 1 (1) and will continue expanding at an ever-increasing 
rate
(2) but will eventually slow down, stop, and then begin 
contracting
(3) and will continue expanding at a decreasing rate 
(4) NVA
(5) NVA