Chapter 5: Formation of Stars and Planets ASTR/PHYS 1060: The - - PowerPoint PPT Presentation

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Chapter 5: Formation

• f Stars and Planets

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Stars form from the “interstellar medium”: gas in between stars

“Pillars of Creation”

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Life Cycle of Gas and Stars

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Which region is hotter and which is colder?

M

• l

e c u l a r C l

• u

d D e n s e & C

• l

d W a r m e r G a s A t

• m

i c & I

• n

i z e d

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

What is temperature?

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If an interstellar cloud contracts to become a star, it is due to which force?

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A) electromagnetic B) nuclear C) gravitational D) all of the above

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• Ch. 5: Formation of Stars/Planets

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HW2 due NOW! Midterm 1 on Sept. 28th will cover Chapters 1-5 and lecture material Moon Phases available up front if you haven’t gotten yours yet

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Life Cycle of Gas and Stars

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

If an interstellar cloud contracts to become a star, it is due to which force?

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A) electromagnetic B) nuclear C) gravitational D) all of the above

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Thermal Pressure Turbulence Magnetic Fields

Gravity has to overcome other forces in the cloud that want to keep it from collapsing

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Thermal Pressure Turbulence Magnetic Fields

Gravity has to overcome other forces in the cloud that want to keep it from collapsing Easier for gravity to do this if the mass of the cloud is: A)Doesn’t Matter B)Large C)Small

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Cloud doesn’t collapse uniformly

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Simulation of the collapse of gas cloud, fragmenting, forming protoplanetary disks and low mass stars

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Conservation of “Angular Momentum”

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Angular Momentum

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• L = m v r
• L is angular momentum
• m is mass
• v is velocity
• r is radius

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Any small net spin of the collapsing cloud is amplified as it becomes smaller

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Protoplanetary Disk

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Observations of Disks

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Orion Nebula

• ld Hubble Telescope data (visual)

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Observations of Disks

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WISE (infrared) ALMA (radio) HL Tauri ALMA (radio)

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Computer Simulations of Protoplanetary Disks

https://www.youtube.com/watch?v=yXq1i3HlumA&feature=youtu.be

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• Ch. 5: Formation of Stars/Planets

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Midterm 1 on Sept. 28th will cover Chapters 1-5 and lecture material HW1 solutions are online HW1 available up front Last name: beginning

• f alphabet to your left

Last name: end of alphabet to your right Are your grades in Canvas correct???

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Evidence of impacts are everywhere!

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Moon Jupiter Mercury Mimas (Saturn) Earth (Meteor Crater)

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

What evidence do we have that our solar system formed from an accretion disk?

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Almost correct observation in Sci Fi

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https://www.youtube.com/watch?v=LAlqp0_a0tE

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Almost correct observation in Sci Fi

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https://www.youtube.com/watch?v=LAlqp0_a0tE

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High Budget ESA PR

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https://www.youtube.com/watch?v=32vlOgN_3QQ

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Rosetta Mission and Philae Lander

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Sun 99.85%

Outer Planets 0.134% Terrestrial Planets 0.001%

Mass Distribution in the Solar System

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What is the solar system made of?

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[Z]

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Inner versus outer planets

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Exoplanets

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

First planets discovered outside the solar system

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1992 - 3 confirmed planets Pulsar PSR B1257+12 Sun-like star: 51 Pegasi b 1995 - a “hot Jupiter”

artist conception artist conception

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

How to find planets

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• Detect them directly
• Detect their influence on their star
• Image the planet
• Detect its atmosphere in a spectrum

• Measure light blocked from the star when

the planet eclipses it

• Measure the star’s motion due to the

planet’s gravity

Direct Imaging Transit Method Radial Velocity Method

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Direct Imaging

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Planet millions of times fainter Need to mask the starlight

0.5” 20 AU

HR 8799

200 AU

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Radial Velocity Method

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Doppler Shift of Light

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λobserved − λemitted λemitted = ∨ c

Which spectrum is moving away from us the fastest?

A B C D

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

• Ch. 5: Formation of Stars/Planets

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Midterm 1 on Sept. 28th will cover Chapters 1-5 and lecture material HW1 solutions are online HW1 available up front Are your grades in Canvas correct???

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Astronomy in the News!

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Japanese satellite Hayabusa 2 visits asteroid Ryugu!

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Binary Stars

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Can’t see the planet, but can see the star

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Motion of the Sun relative to its center

• f mass could be

detectable by (more advanced than us) aliens

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Transit Method

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Starlight is blocked by the planet, reducing the amount of light detected from the star

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

A quick review of orbits…

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Kepler & Kepler

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Kepler Mission

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Kepler’s 3 Laws

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1st Law: Orbits are elliptical 2nd Law: equal areas in equal times 3rd Law: period depends on distance (Period of Planet [in years])2 = (Average Distance of Planet from Star [in AU])3

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

• Ch. 5: Formation of Stars/Planets

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Midterm 1 on Sept. 28th will cover Chapters 1-5 and lecture material Transit Activity due @10:55am (feel free to discuss your answers with your group

• r turn in up front anytime beforehand)

Are your grades in Canvas correct??? Office Hours Mon 12-1pm Zane Tues 1:30-3pm me Tues 5-6pm Randall Wed 3-4pm Randall Thurs 11:45a-12:45pm Zane Fri 12-1pm me me: INSCC 320 Zane/Randall: JFB 325

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

1) Draw a planet orbiting a star - what orientation is required to produce planetary transits? How common do you think that

• rientation is?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

2) What can you learn about the physical properties of the planets from transits based on the data you took (hint: there is more than

• ne thing)?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

3) What is the difference between the planets around Star A and Star C (be as quantitative as possible)?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

4) What is the difference between the planets around Star C and Star D?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

5) How can you explain the results from star B (there are a variety of reasons that we may not see a signal)?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

6) The Earth’s radius is about 100 times smaller than the sun? How sensitive would our light meter have to be to detect its transit?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

How long would you have to

• bserve to find an earth-like

planet around another star?

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Kepler-11 System (6 planets)

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Lissauer et al. 2011

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Kepler Planetary Systems

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https://youtu.be/_DnDeBa0KFc

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What’s Next: TESS

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“First Light” image taken by TESS, released last week - already found 2 new planets! TESS will monitor the brightest stars in the sky for transits, finding planets around the stars nearest to us

Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Biosignatures of Life in an Exoplanet Atmosphere

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

What do you think about the possibility of detecting biosignatures on an Earth-like planet orbiting another star?

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Fall 2018: Chapter 5 ASTR/PHYS 1060: The Universe

Why Pluto is not a planet

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• It is in orbit around the Sun.
• It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
• It has "cleared the neighborhood" around its orbit.

Paper recently out about this 3rd criteria not used historically Charon Pluto