View
51
Download
0
Category
Tags:
Preview:
DESCRIPTION
Chapter 16/Chapter17. Questions of the Day. What are stars? What are their properties? Who was Annie Jump Cannon? Why was she important to the study of stars? What is stellar spectroscopy? What does it tell us about a star? - PowerPoint PPT Presentation
Citation preview
Chapter 16/Chapter17Chapter 16/Chapter17
Questions of the DayQuestions of the Day What are stars? What are their properties?What are stars? What are their properties?
Who was Annie Jump Cannon? Why was she Who was Annie Jump Cannon? Why was she important to the study of stars?important to the study of stars?
What is stellar spectroscopy? What does it tell us What is stellar spectroscopy? What does it tell us about a star?about a star?
What is the Sun? Why is it important to study this What is the Sun? Why is it important to study this particular star?particular star?
Parallax of a StarParallax of a Star
)(" Angle Parallax1(parsec) Distance
Parallax of a StarParallax of a Star
parsecs50.2"1Distance
Parallax1Distance
0.2"Parallax
Differential MagnitudeDifferential Magnitude
12
12
mm
2
1
5.2mm
2
1
12
2
1
12
1
2
121
2
5.2ff
10ff
5.2mm
fflog
5.2mm
fflog
mmfflog5.2
Differential MagnitudeDifferential Magnitude
Two stars have a magnitude of 7 and 3. How Two stars have a magnitude of 7 and 3. How much brighter is the star with a magnitude of 3 much brighter is the star with a magnitude of 3 than the star with a magnitude of 7?than the star with a magnitude of 7?
X40ff
5.2ff
5.2ff
7m3m
2
1
37
2
1
mm
2
1
2
1
12
Distance ModulusDistance Modulus
121
2
21
22
1
2
mmfflog5.2
)parsec10(4Lfd4
(L)Luminosityf
Mmmm
Distance Modulus Distance Modulus
m10dlog5M
Mm10dlog5
Mmd10log5
Mmd10log5.2
Mm)10(4
Ld4
Llog5.2
2
2
2
Distance ModulusDistance Modulus
A star has a absolute magnitude of -5 and a A star has a absolute magnitude of -5 and a distance of 1000 parsecs. What is the distance of 1000 parsecs. What is the magnitude of the star as view from Earth?magnitude of the star as view from Earth?
m5m105
m)100log(55
mpc10pc1000log55
mpc10dlog5M
pc1000d5M
Fig.16.09Fig.16.09
Annie Jump CannonAnnie Jump Cannon
1863 – 1941 A.D.1863 – 1941 A.D. Born in Delaware, Born in Delaware,
grew up in Dover, grew up in Dover, Delaware.Delaware.
Entered Wellsley Entered Wellsley CollegeCollege
http://astro.wsu.edu/worthey/astro/html/im-women/04-cannon.jpg
Annie Jump Cannon’s WorkAnnie Jump Cannon’s Work
Worked under Edward C. Pickering at Worked under Edward C. Pickering at Harvard University to classify spectra of Harvard University to classify spectra of starsstars
1911 - 1914: Created the Henry Draper 1911 - 1914: Created the Henry Draper Catalogue Catalogue
1918: Doctorate Degree1918: Doctorate Degree 1914: Honorary in the Royal Astronomical 1914: Honorary in the Royal Astronomical
SocietySociety
Spectral TypesSpectral Types
http://blueox.uoregon.edu/~courses/BrauImages/Chap17/FG17_010.jpg
Fig.16.18Fig.16.18
Fig.16.19Fig.16.19
Mass – Luminosity Mass – Luminosity
A star has a mass of 5MA star has a mass of 5M, how much brighter is , how much brighter is this star than the Sun?this star than the Sun?
280LL
MM5
LL
MM
LL
M5M
5.3
5.3
What is the Sun?What is the Sun?
Our nearest star.Our nearest star.
The center of our solar system.The center of our solar system.
The main engine for all the heat produced in The main engine for all the heat produced in the solar system.the solar system.
http://spaceflightnow.com/news/n0211/04soho/sun.jpg
What are the properties of the sun?What are the properties of the sun?
Distance: 1.49 X 10Distance: 1.49 X 108 8 km = 1 A.U.km = 1 A.U.
Size: 1.4 X 10Size: 1.4 X 1066 meter = 0.5° meter = 0.5°
Mass: 2 X 10Mass: 2 X 103030 kg kg
Density: 1.4 g/cmDensity: 1.4 g/cm33
Distance to the SunDistance to the Sun
Aristotle was the first person to consider the Aristotle was the first person to consider the problem. But Kepler was the first to obtain a problem. But Kepler was the first to obtain a precise measurement. precise measurement.
Recent measurements use radar bouncing Recent measurements use radar bouncing off other planets to obtain more precise off other planets to obtain more precise measurements.measurements.
Size of the SunSize of the Sun
Aristarchus was the first to consider the size of the Aristarchus was the first to consider the size of the Sun. Sun.
The modern method involves the angle of the light The modern method involves the angle of the light rays.rays.
150 Earths would fit along the diameter of the Sun.150 Earths would fit along the diameter of the Sun.
The Mass of the SunThe Mass of the Sun
Newton was the first person to find Newton was the first person to find accurately the mass of the sun with his accurately the mass of the sun with his theory of gravitation.theory of gravitation.
300,000X more massive than the Earth.300,000X more massive than the Earth.
The Density of the SunThe Density of the Sun
The density is simple calculation of the The density is simple calculation of the mass over the volume.mass over the volume.
The density is only 40 percent higher than The density is only 40 percent higher than water suggesting a gaseous composition.water suggesting a gaseous composition.
The Layers of a StarThe Layers of a Star
CoreCore Radiative ZoneRadiative Zone Convective ZoneConvective Zone PhotospherePhotosphere ChromosphereChromosphere CoronaCorona
http://www.conceptdraw.com/samples/samplestour/Proton/Proton.gif
http://www.uniba.sk/~ago/pics/sun/1907anim.gif
Sun FlareSun Flare
http://msowww.anu.edu.au/msovc/displays/images/sun-flare.jpg
Sunspot CycleSunspot Cycle
http://www.hao.ucar.edu/public/education/sp/images/sunspotn.2.jpg
Homework 7Homework 7 What is the luminosity of the Sun? What is the luminosity What is the luminosity of the Sun? What is the luminosity
of a O type star? And what the luminosity of the K type of a O type star? And what the luminosity of the K type star? How do they compare to the luminosity of the Sun? star? How do they compare to the luminosity of the Sun? And how much heavier is the O than the K type star?And how much heavier is the O than the K type star?
Two stars have magnitudes of 4 and 9 respectively. How Two stars have magnitudes of 4 and 9 respectively. How much brighter is the star with magnitude 4 than the star much brighter is the star with magnitude 4 than the star with magnitude 9? If these two star were the same with magnitude 9? If these two star were the same absolute magnitude (-4), how much further is the star with absolute magnitude (-4), how much further is the star with apparent magnitude of 9 than the star with the apparent apparent magnitude of 9 than the star with the apparent magnitude of 4?magnitude of 4?
Page 391, CQ 3, 12Page 391, CQ 3, 12 Describe the different layers of the Sun via their respective Describe the different layers of the Sun via their respective
temperatures and pressures. temperatures and pressures.
Recommended