Presentation is loading. Please wait.

Presentation is loading. Please wait.

ASTR 1040 First Homework Due Today Next Observatory opportunity 9/26

Published byMarie Espeland Modified over 6 years ago

Similar presentations

Presentation on theme: "ASTR 1040 First Homework Due Today Next Observatory opportunity 9/26"— Presentation transcript:

1 ASTR 1040 First Homework Due Today Next Observatory opportunity 9/26
Planetarium on 9/26 First Exam October 5 Website

2 Fusion vs. Fission Fusion: Atoms unite and release energy (Fuse)
New atom must be no heavier than iron z=26 Fission: Heavy atoms split to release energy Initial atom must be heavier than iron WWII Nukes were fission bombs made of U and Pu Sun works on FUSION of H into He

3 Proton-Proton Chain Bottom Line: H+H+H+H  He 1H1 +1H1  1H2 + e+ + n
1H2 +1H1  2He3 + g 2He3 +2He3  2He4 + 1H1 + 1H1 5x106 < T < 2x107K

4 CNO Cycle 6C12 +1H1  7N13 + g 7N13  6C13 + e+ + n
7N14 +1H1  8O15 + g 8O15  7N15 + e+ + n 2x107 < T < 108K 7N15 +1H1  6C12 + 2He4 Net: 1H1 +1H1 + 1H1 +1H1  2He4 + 2e+ + 4g +2n hydrogen -> helium + energy

5 Triple-a Reaction 2He4 +2He4  4Be8 + g 4Be8 +2He4  6C12 + g
T > 108K 4Be8 +2He4  6C12 + g Must be very dense for this to work Be8 decays back into helium very quickly unless struck by another He4 Too low density in Big Bang Net: 2He4 +2He4 + 2He4 +2He4  6C12 + 2g helium -> carbon + energy

6 Solar Schematic

7 Sunspots Seen by Ancient Persians

8 Groups of Sunspots

9 Solar Corona Visible in Eclipse

10 The 1999 Eclipse

11 August 21, 2017

12 The Sun Viewed in X-rays

13 X-ray Movie

14 X-ray Loops

15 Magnetic Structure

16 Dynamic Structure

17 Solar Turbulence

18 Differential Rotation
Rotates in 25 days at Equator 28 days Mid Latitude 30 days Poles Rapidly Twists Up

19

20

21 Pressure Balance P=1.5nkT P=B2/8
n is particles per cm3 k = 1.4x10-16 in cgs units (Boltzman’s Constant) T is temperature in Kelvins P=B2/8 B is magnetic field in Gauss P is pressure in ergs/cm3 = dynes/cm2

22 Example B= 0.3G (about Earth) PB = 0.32 / 8 /3.14 = 3.5x10-3 erg/cm3
Patmosphere = 1.5nkT = 1.5x2.5x1019x1.4x10-16x300 = 1.5x106 erg/cm3 That’s why the weather report never includes the magnetic activity of the Earth

23 Sunspots Erupt in Groups

24 During mid 1600’s sunspots became non-existent
Sunspot Cycle During mid 1600’s sunspots became non-existent Maunder Minimum

25 Solar Wind 5x105K Corona 2x106K Photosphere 5500K
Transition Region 105K Chromosphere 104K Photosphere 5500K

26 Solar Wind Passes Earth

27 Summary: Sun as a Star Formed from cloud 4.6x109 years ago
Collapsed to present size stabilized by nuclear reactions Emits 4x1026 W Runs on proton-proton chain and CNO cycle Now 20% brighter Turbulent upper envelope Magnetic Fields from Differential Rotation Sunspots, Corona, Solar Wind Activity Cycle 11 years

28 STARS

29 Stars are grouped in Galaxies
Sun and all the stars we see are part of Milky Way Galaxy We all orbit a common center Sun is 3x1020m from center of MW You are here Each star orbits center Disk Stability Again

30 Distances to the Stars Closest Star, Proxima Centauri is 4x1016m away. (Alpha Cen ~4.3x1016m) Need a more convenient unit

31 The Light Year Light Travels at 300,000km/s (186,000miles/s = 3x108m/s) That’s one foot per nanosecond One Year is 3.15x107 seconds long In one year light travels 3.15x107x3x108 = 1016m This is the definition of a light year. Prox Cen is at 4ly.

32 Question There’s a big black hole in the Center of the Milky Way at a distance of 3x1020m. How long does it take for its light to reach us? A) 3years B) 30 years C) 300 years D) 3000 years E) 30,000 years

33 Question There’s a big black hole in the Center of the Milky Way at a distance of 3x1020m. How long does it take for its light to reach us? A) 3years B) 30 years C) 300 years D) 3000 years E) 30,000 years

34 The Parsec Astronomers use the parsec as a measure of distance 1pc = 3ly 1pc = 3x1016m Origin of parsec comes from method of measuring distance

35 Each Star Orbits the Center

36 How Long does that Take? Takes about a hundred million years to circumnavigate the galaxy

37 Star Names Arabic Names Constellations
Antares, Capella, Mira, etc. Constellations a Orionis, b Cygni, … then 49 Ori, 50 Ori, etc. Catalogues HD80591, SAO , etc RA and Dec – just position in the sky

38 Proper Motion 2003 All stars move Nearby stars move faster
Appear to move against fixed field Can Take Many Years Use Old Photographic Plates 1900

39 Parallax I year cycle

40 The Parsec 1 parsec 360 degrees in circle 60 arcminutes per degree
1AU 1 arcsecond 360 degrees in circle 60 arcminutes per degree 60 arcseconds per arcminute 200,000AU = 1 parsec = 3x1016m parsec parallax second

41 Question Based on the definition of a parsec , if star A has a parallax of 0.5 arcseconds and star B has a parallax of 0.75 arcseconds which one is farther from the Earth? A. Star B is farther away because it has a higher parallax B. Star A is farther away because it has a lower parallax C. All stars are the same distance away from the Earth D. It is impossible to tell from this information.

42 Question Based on the definition of a parsec , if star A has a parallax of 0.5 arcseconds and star B has a parallax of 0.75 arcseconds which one is farther from the Earth? A. Star B is farther away because it has a higher parallax B. Star A is farther away because it has a lower parallax C. All stars are the same distance away from the Earth D. It is impossible to tell from this information.

43 Measure Parallax distance to a star in parsecs = 1/(parallax in arcseconds) e.g. measure .04” parallax, then distance is 25pc Measuring Parallax was first successful way to measure distances to stars after centuries of trying Took high speed photography in 1890’s to do it.

44 Question The parallax of an observed star is 0.1 arcseconds, how many lightyears is it away from Earth? a. 1 light year b. 3 light years c. 10 light years d. 30 light years e. 75 light years

45 Question The parallax of an observed star is 0.1 arcseconds, how many light years is it away from Earth? a. 1 light year b. 3 light years c. 10 light years d. 30 light years (10parsecs) e. 75 light years

Download ppt "ASTR 1040 First Homework Due Today Next Observatory opportunity 9/26"

Similar presentations

PHOTOSPHERE The lowest layer of the Suns atmosphere that is also the visible part we see.

PHOTOSPHERE The lowest layer of the Suns atmosphere that is also the visible part we see.
Stars and Galaxies The Sun.

Stars and Galaxies The Sun.
The Sun – Our Star Chapter 7:. General Properties Average star Absolute visual magnitude = 4.83 (magnitude if it were at a distance of 32.6 light years)

The Sun – Our Star Chapter 7:. General Properties Average star Absolute visual magnitude = 4.83 (magnitude if it were at a distance of 32.6 light years)
The Sun’s Structure & Features Chapter 26.1 Chapter 26.1 70% H 28% He The sun is made up of gas Temps: 15 million K at core / 5000 K at surface The sun.

The Sun’s Structure & Features Chapter 26.1 Chapter % H 28% He The sun is made up of gas Temps: 15 million K at core / 5000 K at surface The sun.
The Sun Chapter 7:. General Properties Average star Absolute visual magnitude = 4.83 (magnitude if it were at a distance of 32.6 light years) Central.

The Sun Chapter 7:. General Properties Average star Absolute visual magnitude = 4.83 (magnitude if it were at a distance of 32.6 light years) Central.
This Set of Slides This set of slides covers our Sun, nuclear processes, solar flares, auroras, and more… Units covered 49, 50, 51.

This Set of Slides This set of slides covers our Sun, nuclear processes, solar flares, auroras, and more… Units covered 49, 50, 51.
ASTR 1200 Announcements Website Second problem set due next Tuesday in class. Observatory Sessions.

ASTR 1200 Announcements Website Second problem set due next Tuesday in class. Observatory Sessions.
The Sun Earth Science - Mr. Gallagher. The Sun is the Earth's nearest star. Similar to most typical stars, it is a large ball of hot electrically charged.

The Sun Earth Science - Mr. Gallagher. The Sun is the Earth's nearest star. Similar to most typical stars, it is a large ball of hot electrically charged.
Structure & Function. Our Nearest Star  Core  Comprises about 25% of sun’s interior  site of nuclear fusion  Radiative Zone  Energy produced in.

Structure & Function. Our Nearest Star  Core  Comprises about 25% of sun’s interior  site of nuclear fusion  Radiative Zone  Energy produced in.
Stars, Galaxies, and the Universe Chapter 22 Page 752.

Stars, Galaxies, and the Universe Chapter 22 Page 752.
Stars and Galaxies.

Stars and Galaxies.
The Sun By: Kristel Curameng and Courtney Lee. The Sun The Sun is the most prominent feature in our solar system. The largest object and contains approximately.

The Sun By: Kristel Curameng and Courtney Lee. The Sun The Sun is the most prominent feature in our solar system. The largest object and contains approximately.
From the Core to the Corona – a Journey through the Sun

From the Core to the Corona – a Journey through the Sun
The Sun. Components of the Sun Core Radiative zone Convective zone Atmosphere –Photosphere –Chromosphere –Corona Solar wind (mass loss)

The Sun. Components of the Sun Core Radiative zone Convective zone Atmosphere –Photosphere –Chromosphere –Corona Solar wind (mass loss)
The Sun.

The Sun.
Stars Chapter 25. The Sun The Sun’s mass controls the motions of the planets Less dense than Earth High pressure and temperature causes gases to be plasma.

Stars Chapter 25. The Sun The Sun’s mass controls the motions of the planets Less dense than Earth High pressure and temperature causes gases to be plasma.
The Sun Stellar Evolution: Low Mass Stars White Dwarfs

The Sun Stellar Evolution: Low Mass Stars White Dwarfs
Nuclear fusion reaction –In essence, 4 hydrogen nuclei combine (fuse) to form a helium nucleus, plus some byproducts (actually, a total of 6 nuclei are.

Nuclear fusion reaction –In essence, 4 hydrogen nuclei combine (fuse) to form a helium nucleus, plus some byproducts (actually, a total of 6 nuclei are.
Star Life Cycle Review. Transports energy from the radiative zone to the surface of the sun. Sunspot Corona Photosphere Convective zone.

Star Life Cycle Review. Transports energy from the radiative zone to the surface of the sun. Sunspot Corona Photosphere Convective zone.
PHYS 1621 Proton-proton cycle 3 steps. PHYS 1622 Layers of the Sun Mostly Hydrogen with about 25% Helium. Small amounts of heavier elements Gas described.

PHYS 1621 Proton-proton cycle 3 steps. PHYS 1622 Layers of the Sun Mostly Hydrogen with about 25% Helium. Small amounts of heavier elements Gas described.

Similar presentations

Ads by Google