HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
For any given temperature, giant stars are brighter than main
sequence stars. They must be brighter due to extra surface
area.
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
For any given temperature, giant stars are brighter than main
sequence stars. They must be brighter due to extra surface
area.
RQ10!What evidence shows that white dwarfs must be very
small?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
For any given temperature, giant stars are brighter than main
sequence stars. They must be brighter due to extra surface
area.
RQ10!What evidence shows that white dwarfs must be very
small?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
For any given temperature, giant stars are brighter than main
sequence stars. They must be brighter due to extra surface
area.
RQ10!What evidence shows that white dwarfs must be very
small?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 RQ8! Why does the luminosity of a star depend on both its radius
and its temperature?
Temperature determines the energy output rate per square
meter. The radius determines the number of square meters.
So light output will depend on both temperature and radius.
RQ9! How can you be sure that the giant stars really are larger
than main sequence stars?
For any given temperature, giant stars are brighter than main
sequence stars. They must be brighter due to extra surface
area.
RQ10!What evidence shows that white dwarfs must be very
small?
We observe that white dwarfs are hotter than the Sun but
much dimmer. Therefore they must be smaller.
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 L2L 2: If all the stars in the photo here are members of the same
star cluster, then they all are about the same distance from Earth.
Then why are three of the brightest much redder than the rest?
What kind of star are they?
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 L2L 2: If all the stars in the photo here are members of the same
star cluster, then they all are about the same distance from Earth.
Then why are three of the brightest much redder than the rest?
What kind of star are they?
Since the are red (lower
surface temperature), they
must be bright by being
large. I think these are
probably red giants or red
supergiants.
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 SQ8! Use Figure 9-12 on page 180 of your textbook to
approximate the following values:
(a) The surface temperature of Procyon B
8000K
(b) The radius of Betelgeuse
1000R☉
(c) The radius of Sirius B
less than 0.01R☉
(d) The luminosity of Altair
10L☉
(e) The absolute magnitude of Capella A
0
(f) The spectral type of Alnilam
O9
HW 6-5: (196) RQ 8-10; (197) L2L 2; Supp Qs 8-9 SQ9! Use Figure 9-16 on page 183 of your textbook to
approximate the following values:
(a) The luminosity of an A5Ia star
100,000L☉
(b) the luminosity of a K2V star
0.1L☉
(c) The surface temperature of a B3
star (independent of luminosity class)
20,000K
(d) The spectral type of a star with
surface temperature of 3000K
(independent of luminosity class)
M2