Astrophysics Flashcards

1
Q

Intensity Ratio

A

1A/1B = 2.512MB-MA

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2
Q

Magnitude Difference

A

MA-MB = 2.5log(1A/1B)

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3
Q

Small Angle Formula

A

angular diameter-arcseconds/206265 = linear diameter/distance

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4
Q

Circular Velocity

A

VC = squareroot(GM/r-meters)

M = mass of central body (kg)

G = 6.67x10-11 m3/s2kg

* Answer in m/s

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5
Q

Compare LGP

A

LGPA/LGPB = (DA/DB)2

D = diameter

* Answer in times (x)

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6
Q

Resolving Power

A

a = 11.6/D(cm)

D = diameter (cm)

* Answer in arcseconds

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7
Q

Magnification

A

M = FO/FE

FO = focal length of objective

FE - focal length of eyepiece

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8
Q

Wien’s Law

A

~max = 3,000,000/T-degrees Kelvin

* Answer in nm

~max = .2987/T x 108Å

T = 2.9x108Å/peak ~

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9
Q

Stefan-Boltzmann Law

A

E = σT4(J/s/m2)

T = K

σ = 5.67 x 10-8J/m2s degree4

* Answer in J

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10
Q

Doppler Formula

A

Vr/c = triangle~/~o

Vr = radial velocity

c = 300,000 km/s

triangle~ = change in ~

~o = observed ~

(lmaoo you’re prob laughing when u see this)

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11
Q

Fusion Explained

A

E = mc2

m = kg

c = 3x108 m/s

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12
Q

Distance to Star

A

d = 206,265/p-arcseconds

p=parallax

* Answer in AU

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13
Q

F Ratio

A

focal length(mm)/objective diameter(mm)

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14
Q

Distance Modulus

A

mv - Mv = -5 + 5log(d)

d = 10 mV-MV+5/5 = pc

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15
Q

Luminosity of Star

A

L/Lo = (R/Ro)(T/To)

* Answer in times (x)

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16
Q

Mass of Binary System

A

MA + MB = a3/p2

M= solar masses

p = orbital period (yrs)

a = AU

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17
Q

Kepler’s 3rd Law

A

p2 = a3

p = orbital period (yrs)

a = distance (AU)

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18
Q

Mass-Luminosity Relation

A

L = M3.5

M = star mass in Mo

* Answer in times (x)

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19
Q

Life Expectancy

A

T = 1/M2.5

M = star mass in Mo

* Answer in O lifetimes x 10 billion = years

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20
Q

Schwarzschild Radius

A

RS = 2GM/C2

G = 6.67 x 10-11 m3/s2kg

C = 3 x 108 m/s

M = mass (kg)

* Answer in m

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21
Q

Hubble Law

A

Vr = Hd

Vr = velocity of recession of galaxy (km/s)

H = 20km/s/Mpc

d = distance (Mpc)

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22
Q

Redshift

A

Z = triangle~/~o

triangle~ = change in ~

~o = unshifted ~

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23
Q

Age of Universe

A

TU = 1/H x 1012years

H = 70 km/s/Mpc

* Answer in years

24
Q

Distance-Rate-Time

A

d = rt

r = d/t

t = d/r

25
Newton's Law of Gravity
F = Gm1m2/r^2 G = 6.67 x 10-11 m3/s2kg m1m2 = masses of objects in kg r = distance between the two masses (m) F = the strength of the gravitational force (N)
26
Kepler's 1st Law (Eccentricity)
e = c/a
27
Ratio
distance/(size/separation)
28
Frequency
v = c/~
29
1 AU
1.495979 x 1011m
30
1 parsec (AU)
206,265 AU
31
1 parsec (m)
3.085678 x 1016m
32
1 parsec (light years)
3.261633 light years
33
1 light year
9.46053 x 1015m
34
c, or the speed of light
2.997925 x 108m/s
35
G, or the gravitational constant
(6.67 x 10(-11)) + (m3/s2)/kg
36
M+
5.976 x 1024kg
37
R+
6,378.164 km
38
Mo
1.989 x 1030kg
39
Ro
6.9599 x 108m
40
Lo
3.826 x 1026kg
41
M of the Moon
7.350 x 1022 kg
42
R of the Moon
1738 km
43
M of H atom
1.67352 x 10-27 kg
44
1 arc minute (1')
1/60o
45
1 arc second (1")
1/60'
46
1 Megaton
1,000k000 of TNT = 4.5 x 1015 J
47
Gravity
6.67x10^-11Nm2/kg2
48
Force
F = G x m1m2/r2
49
Eccentricity
e2 = 1 -b2/a2
50
Barycenter
ma/mb = rb/ra m = mass r = distance
51
Keplar's 3rd Law
p2 = (4π2/GM)a3 G = gravitational constant M = mass of centeal object P = solar years
52
Keplar's 2nd Law
rotation of the a planet around a focal point results in the same time lapse passed over two opposite, but similar given areas. This proves acceleration as we near the focal point
53
1a supernovae
caused by white dwarves gaining mass of over 1.4 solar masses from its companion in a binary system all 1a supernovaes have the same brightness and can determine intergalatic distances. They are brighter than type II
54
Type II supernovae
stars must be 8+ solar masses. Iron production because as elements run out for fusion. Heavy elements \> atomic #26 are created in supernovae
55
Pulsars
stars core must be 1.4-3.2 solar masses. Emits beans of radiation at magnetic poles.
56
H-R Diagram
relates the absolute magnitudes and luminosities of stars with spectral types and temps. Can reveal characteristics in stars and predict locations of new stars. Measured in kelvin or spectral class (O B A F G K M)