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Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s...

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LAB 11 Astronomy 105 Laboratory
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Page 1: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

LAB 11

Astronomy 105 Laboratory

Page 2: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

AST 105Review for Lab Exam

Page 3: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Ast 105 Lab ExamWeek of April 16, at normal lab time.

Don’t be late!!

Items to bring…- One scantron (882-E)

- two pencils

Page 4: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Study!

About 3-5 questions from each lab exercise

Review

Main concepts covered

Procedures and measurements

Questions and calculations

Bring a scantron: 882-E

Review material – Power point slides online

Page 5: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

CONSTELLATIONS – SKY

FAMILIARIZATION

Page 6: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

North

South

Celestial Equator

Ecliptic Sun’s Path

Eas

t

Summer

Solstice

Vernal

Equinox

Autumnal

Equinox

Page 7: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

North

South

East

March 7 @ 8:00 p.m

Meridian

Zenith

32° X

West Horizon

Page 8: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

March 7 @ 8:00 p.m

Meridian

not visible

WestEast

East HorizonWest Horizon

Page 9: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Sky Familiarization

A Few More Things to Remember

Any vertical line on your SC-1 (north-south) is a

meridian.

Approximately one half of the stars on the SC-1

are visible at any given time (12 hours of RA).

Meridian moves eastward 4 minutes each day

(Earth’s revolution)

Meridian moves eastward 1 hour of RA for every

hour of time (Earth’s rotation)

Page 10: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

SCIENTIFIC

MEASUREMENTS

Page 11: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Scientific Experiments / Observations

Physical quantities can never be

measured with absolute precision

Page 12: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

How Many Significant Figures

0.089 2

1.089 4

12000 2

12001 5

Page 13: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Scientific Notation

3.502 x 106

decimal number (1-9)10 raised to an

integer power

Number Significant Figures Scientific Notation

9004 4 9.004 x 103

0.000007 1 7 x 10-6

43 2 4.3 x 101

7,805,000,000 4 7.805 x 109

0.0408 3 4.08 x 10-2

8.4 2 8.4 x 100

Page 14: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

To multiply two numbers in scientific notation multiply the

decimal parts of the numbers and add the exponents

algebraically.

(4.0 x 104)(2.0 x 103) =

(4.0 x 2.0)(104 x 103) =

(8.0) x (104+3) =

8.0 x 107

(6.0 x 102)(2.0 x 105) = 12.0 x 107 = 1.2 x 108

Page 15: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Units

Provides numerical context for a measurement

Unit conversion

Ex. Convert 500 kilometers into centimeters

1000 m = 1 km 1 m = 100 cm

500 𝑘𝑚 ×1000 𝑚

1 𝑘𝑚×100 𝑐𝑚

1 𝑚= 5 × 107cm

1000 𝑚

1 𝑘𝑚= 1 and

100 𝑐𝑚

1 𝑚= 1

Page 16: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

THE MOON

Page 17: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

N.P.N.P. N.P.

N.P.

N.P.

Synchronous

Rotation

Does the Moon rotate on it’s axis?

What is the Moon’s hidden side?

Page 18: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

N.P. Noon

Sunset

Midnight

Sunrise

N.P. Noon

Sunset

Midnight

Sunrise

N.P. Phase: 1st quarter

Rise Time:

Set Time:

Transit:

Noon

Midnight

Sunset

Page 19: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

MERCURY’S ORBIT

Page 20: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @
Page 21: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

10 20 30 40 50 60 70 80 90 100010 km

6

SUN

Name (print):__________________________________ Section: _____

0.70.60.50.40.30.20.10.0AU

0.8

110 120

Mercury’s Orbit

Major Axis

Equal Time Intervals

F F

Verifying Kepler’s 1st

Page 22: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Mercury’s Orbit

Major Axis

10 20 30 40 50 60 70 80 90 100010 km

6

SUN

0.70.60.50.40.30.20.10.0AU

0.8

110 120

Verifying Kepler’s 2nd

Equal area in equal time.

Page 23: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Mm

a

G

4πP

322

2

324

P

a

GMm sunm

sunsunm MMm

Kepler’s 3rd

)(

4 2

MmGk

2

324

P

a

GM sun

Finding the Sun’s mass.

P2=ka3

Page 24: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

EMISSION SPECTRA

Page 25: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @
Page 26: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Formation of Emission and Dark Line Spectra

Page 27: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @
Page 28: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @
Page 29: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

THE EARTH’S ORBITAL VELOCITY

Page 30: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

1

2

3

4

5

Velocity = 0

Increasing

Velocity

Increasing

Velocity

The Doppler Effect

o

r

cv

Page 31: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Arcturus

VA

VB

? ?

0A

λ

Δλcv

o

From measured

Doppler Shift

1.Orbital velocity of Earth

2.Radial velocity of Arcturus

3.Radius of the Earth’s Orbit

Page 32: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

THE HR DIAGRAM

Page 33: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Apparent Brightness of Stars

Stellar Luminosity -- Total amount of light

energy emitted each second

Surface Area

Temperature

Distance from the Earth

Page 34: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Magnitude

Stellar Brightness

Apparent Magnitude (mv) - Brightness from Earth

Absolute Magnitude (Mv) - Brightness from 10 pc

Absolute magnitude depends only on a star’s luminosity (the star’s wattage)

Magnitude Difference

Brightness Ratio (Brightness Difference)

1 (2.512)1

2.5 2 (2.512)

2 6.3

3 (2.512)3 15.9

4 (2.512)4 40

5 (2.512)5 100

6 (2.512)6 251

Page 35: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Spectral Classification

B

Page 36: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

The Sun

M=+5 G2

O B A F G K M

-10

-5

0

+5

+10

+15Ab

so

lute

Mag

nit

ud

e

Temperature

HR Diagram

Page 37: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Luminosity Class

Size

Ia & Ib Supergiant

II Bright Giant

III Giant

IV Sub-giant

V Dwarf

The Sun’s Spectral and Luminosity Class: G2 V

Page 38: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Star mv Mv

Spectral

Type

Luminosity

Class

Aldebaran +0.9 -0.2 K5 III

Alpha Centauri A 0.0 +4.4 G2 V

Antares +0.9 -4.5 M1 I

Canopus -0.7 -3.1 F0 II

Fomalhaut +1.2 +2.0 A3 V

Regulus +1.4 -0.6 B7 V

Sirius -1.4 +1.4 A1 V

Spica +0.9 -3.6 B1 V

Which star appears faintest in our sky? Regulus

Which star has the greatest luminosity?

Which star has the highest surface temperature?

Which star is a red giant?

Which main-sequence star has the longest lifetime?

Antares

Spica

Aldebaran

Alpha Centauri

Page 39: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

STELLAR PARALLAX

Page 40: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

1 AU

Sun

Earth

Star 1 Star 2 Star 3

1 arcsec

1/2 arcsec

arcsec

1/3 arcsec arcsec

1 pc 2 pc 3 pc

1 parsec 2 parsec 3 parsec

A star with a parallax of 1 arcsecond is at a distance of 1 parsec (1 pc = 3.26 ly)

5 light-years 10 light-years

More distant stars have smaller parallaxes.

=1

A star’s distance in parsecs is given by

where d is in parsecs and p is in arcseconds

Stellar Parallax

• Motion of Earth cause parallax shifts

• Used to find distance to stars out to a few hundred light-years

• Parallax is ½ of measured shift

• More distant stars have a smaller parallax… a star with ½ the parallax

of another star is 2x farther away

• d = 1 / p “p” is in arc seconds and “d” is in parsecs

Page 41: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

THE PLEIADES

Page 42: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Stars in a Cluster•Common Properties

•Distance

•Age

•Different Properties

•Spectral Types (temperature)

• Luminosity Class (size)

Page 43: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

d >10 pc

10 pc

d <10 pc

10 pc

Star Cluster

d >10 pc

d <10 pc

O B A F G K M

-0.4 color index 1.3

Main-sequence

HR Diagram

-0.4 color index 1.3

Color-Magnitude

Diagram

Distance Modulus = m - M

The difference between the absolute magnitude and

the apparent magnitude can be used to find the

distance to a star cluster.

If m-M > 0 then the distance to the cluster is > 10 pc.

If m-M = 0 then the distance to the cluster is = 10 pc.

If m-M < 0 then the distance to the cluster is < 10 pc.

DM{

Page 44: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Cluster A: Distance 50 ly

Cluster B: Distance ?

The apparent brightness of the

stars in Cluster B are 4 times

fainter than the stars in Cluster A.

What is the distance to Cluster B?

Inverse-Square Law: √4 = 2

Cluster B is 2 times farther or 100 ly.

Page 45: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

AGES AND DISTANCES TO CLUSTERS

Page 46: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Interstellar Dust Reddens Light (makes stars appear cooler)

Dims Light (makes stars appear further away)

Page 47: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

age of cluster = lifetime of stars

at main-sequence turnoff point

B6 stars -- 60 million yrs.

MS lifetime

Pleiades - Open Cluster

Distance - 380 ly Age - 60 million years

Page 48: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

HUBBLE’S LAB

Page 49: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

V = 0 2800210014007007001400

km/sec

10 Mpc 20 Mpc 30 Mpc 40 MpcMilky Way A B C

V = 02800 2100 14007007001400

km/sec

10 Mpc 20 Mpc30 Mpc40 Mpc

Milky Way A B C

10 Mpc20 Mpc Alien’s Galaxy

Recessional Velocity is Proportional to Distance

The Universe is Expanding!!

Page 50: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

v = Ho dHubble Diagram

Finding a Galaxy’s Distance Hubble’s Law

d = v / Ho

To Find Distance:

Measure recessional velocity (red shift)

132 Mpc

Page 51: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Sample Galaxies

Distance

images

Recessional Velocity

spectra

Page 52: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

v = Ho x dHubble Diagram

Hubble Diagram

Procedure

- plot data

- draw best fit line

- find slope (Ho)x

x

x

x

x

rise

runslope = rise/run

Page 53: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

ROTATION OF SATURN

Page 54: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @
Page 55: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Earth Distant Star

Laboratory - No Radial motion

Radial Velocity = 0

Radial Velocity -

Radial Velocity +

Laboratory Spectrum

Blueshift

Redshift

Spectral Lines Match

o

Page 56: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Earth Distant Star

Laboratory - No Radial motion

Radial Velocity = 0

Radial Velocity -

Radial Velocity +

Laboratory Spectrum

Blueshift

Redshift

Spectral Lines Match

o

o

cΔλv

Radial Velocity -

Radial Velocity +

The Doppler Effect: Measuring the Radial Velocity of a Star

Page 57: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Important: Do not write or mark on theSaturn Handout

Page 58: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Spectroscope Slit

No Doppler Shift from

this Light

Light from here

shows the largest

Blue Shift

Light from here

shows the largest

Red Shift

Page 59: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

A

BSaturn

c

VλΔλ 0B 2

o A

B

sec

km

04λ

ΔλcV

V

V

ΔλcV Doppler

c

VλΔλ 0A 2

Page 60: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

o

sec

km

04λ

ΔλcV

Top

Bottom

(mm) = Top Distance – Bottom Distance

Reference

Line

c = 300,000 km/s

o = 6200 Å

Page 61: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

Finding the Rotation Period of Saturn

Saturn

V Period = Distance / Velocity

Distance = Equatorial Circumference = 2RR

P = 2 R / V

V

R2P

Period (P) – Rotation Period

Page 62: Astronomy 105 Laboratory LAB 11 - SFA Physics, Engineering ...Celestial Equator Ecliptic Sun’s Path t Summer Solstice Vernal Equinox Autumnal Equinox. North South East March 7 @

THE END


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