Chapter 5: Formation of Stars and Planets ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 1
Stars form from the “interstellar medium”: gas in between stars “Pillars of Creation” ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 2
Life Cycle of Gas and Stars ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 3
A M t D o o W e l m e a n Which region is hotter c i r s c m u e l & a e & r r I and which is colder? o C C G n o l a o i z l s d u e d d ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 4
What is temperature? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 5
If an interstellar cloud contracts to become a star, it is due to which force? A) electromagnetic B) nuclear C) gravitational D) all of the above ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 6
Ch. 5: Formation of Stars/Planets HW2 due NOW! Moon Phases available up front if you haven’t Midterm 1 on Sept. 28th gotten yours yet will cover Chapters 1-5 and lecture material ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 7
Life Cycle of Gas and Stars ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 8
If an interstellar cloud contracts to become a star, it is due to which force? A) electromagnetic B) nuclear C) gravitational D) all of the above ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 9
Gravity has to overcome other forces in the cloud that want to keep it from collapsing Thermal Pressure Turbulence Magnetic Fields ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 10
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: Thermal Pressure Turbulence Magnetic Fields A)Doesn’t Matter B)Large C)Small ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 11
Cloud doesn’t collapse uniformly ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 12
Simulation of the collapse of gas cloud, fragmenting, forming protoplanetary disks and low mass stars ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 13
Conservation of “Angular Momentum” ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 14
Angular Momentum • L = m v r • L is angular momentum • m is mass • v is velocity • r is radius ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 15
Any small net spin of the collapsing cloud is amplified as it becomes smaller ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 16
Protoplanetary Disk ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 17
Observations of Disks Orion Nebula old Hubble Telescope data (visual) ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 18
Observations of Disks HL Tauri WISE (infrared) ALMA (radio) ALMA (radio) ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 19
Computer Simulations of Protoplanetary Disks https://www.youtube.com/watch?v=yXq1i3HlumA&feature=youtu.be ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 20
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Ch. 5: Formation of Stars/Planets Midterm 1 on Sept. 28th will cover Chapters 1-5 and lecture material HW1 solutions are online Last name: beginning Last name: end of HW1 available up front of alphabet to your left alphabet to your right Are your grades in Canvas correct??? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 24
Evidence of impacts are everywhere! Earth (Meteor Crater) Moon Jupiter Mercury Mimas (Saturn) ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 25
What evidence do we have that our solar system formed from an accretion disk? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 26
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Almost correct observation in Sci Fi https://www.youtube.com/watch?v=LAlqp0_a0tE ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 29
Almost correct observation in Sci Fi https://www.youtube.com/watch?v=LAlqp0_a0tE ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 30
High Budget ESA PR https://www.youtube.com/watch?v=32vlOgN_3QQ ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 31
Rosetta Mission and Philae Lander ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 32
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Mass Distribution in the Solar System Outer Planets 0.134% Sun 99.85% Terrestrial Planets 0.001% ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 34
What is the solar system made of? [Z] ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 35
Inner versus outer planets ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 36
Exoplanets ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 37
First planets discovered outside the solar system Pulsar PSR B1257+12 Sun-like star: 51 Pegasi b artist conception artist conception 1992 - 3 confirmed planets 1995 - a “hot Jupiter” ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 38
How to find planets Direct Imaging • Image the planet • Detect them directly • Detect its atmosphere in a spectrum Transit Method • Measure light blocked from the star when • Detect their influence on their star the planet eclipses it • Measure the star’s motion due to the planet’s gravity Radial Velocity Method ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 39
Direct Imaging Planet millions of times fainter Need to mask the starlight 200 AU HR 8799 0.5” 20 AU ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 40
Radial Velocity Method ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 41
Doppler Shift of Light A λ observed − λ emitted = ∨ c λ emitted B Which spectrum is moving away C from us the fastest? D ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 42
Ch. 5: Formation of Stars/Planets 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??? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 43
Astronomy in the News! Japanese satellite Hayabusa 2 visits asteroid Ryugu! ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 44
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Binary Stars ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 53
Can’t see the planet, but can see the star ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 54
Motion of the Sun relative to its center of mass could be detectable by (more advanced than us) aliens ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 55
Transit Method Starlight is blocked by the planet, reducing the amount of light detected from the star ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 56
A quick review of orbits… Kepler & Kepler ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 57
Kepler Mission ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 58
Kepler’s 3 Laws 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 ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 59
Ch. 5: Formation of Stars/Planets Office Hours Midterm 1 on Sept. 28th will cover Chapters 1-5 and lecture material Mon 12-1pm Zane Tues 1:30-3pm me Transit Activity due @10:55am Tues 5-6pm Randall (feel free to discuss your answers with your group Wed 3-4pm Randall or turn in up front anytime beforehand) Thurs 11:45a-12:45pm Zane Fri 12-1pm me me: INSCC 320 Zane/Randall: JFB 325 Are your grades in Canvas correct??? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 60
1) Draw a planet orbiting a star - what orientation is required to produce planetary transits? How common do you think that orientation is? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 61
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 one thing)? ASTR/PHYS 1060: The Universe Fall 2018: Chapter 5 � 62
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