AST4930: Star and Planet Formation. Syllabus. AST4930: Star and Planet Formation, Spring 2014

Transcription

1 AST4930: Star and Planet Formation Lecture 1: Overview Assoc. Prof. Jonathan C. Tan Bryant 302 Syllabus AST4930: Star and Planet Formation, Spring 2014 Assoc. Prof. Jonathan C. Tan astro.ufl.edu) Tue. periods 5 & 6 (11.45am pm; 12.50pm pm) Thur. period 6 (12.50pm pm) My office is 302 Bryant and my office hours are Thur. 1.40pm-2.40pm, or by appointment. The website for the class is Primary textbook: Stahler, S. & Palla, F. The Formation of Stars (Wiley) (ISBN ). We will also make use of Lecture notes on the formation and early evolution of planetary systems by Phil Armitage PDF slides of the class notes will be available on the course web site. Your final grade will be determined by your homework (30%), midterm exam (20%), final exam (30%) and oral presentation & term paper (20%). The midterm exam will be in class on Thur. 27th Feb. at 12.50pm pm. The final exam will be in class on Tue. 22nd April at 11.45am pm.

2 Course Outline (approximate): 1. Introduction & Overview (S&P Ch. 1) 2. The Interstellar Medium (S&P Ch. 2) 3. Molecular Clouds (S&P Ch. 3) 4. Young Stellar Systems (S&P Ch , 4.5) 5. Molecular Transitions (S&P Ch ; 6.1) 6. Heating, Cooling and Cloud Thermal Structure (S&P Ch. 7, ) 7. Cloud Equilibrium and Gravitational Collapse (S&P Ch , 10.4) 8. Protostars and accretion disks (S&P Ch ) 9. Multiple Star Formation (Binaries & Clusters) (S&P Ch. [12]) 10. Feedback from forming and young stars (S&P Ch. [13], [15]) 11. Galactic and Extra-galactic Star Formation (S&P Ch. [19]) 12. Protoplanetary disks, including disk evolution (Armitage Sect. II) 13. Models of Planet Formation (Armitage Sect. III) 14. Extrasolar Planets (Class Notes) Useful websites Astronomy Picture of the Day: The Smithsonian/NASA Astrophysics Data System: Spitzer Space Telescope: Hubble Space Telescope: Herschel Space Observatory: ALMA:

3 Astronomy Picture of the Day <<The dust sculptures of the Eagle Nebula are evaporating, as powerful starlight whittles away these cool cosmic mountains. This is one of several striking dust pillars of the Eagle Nebula, ten light years tall. The greater Eagle Nebula, M16, is actually a giant evaporating shell of gas and dust inside of which is a growing cavity filled with a spectacular stellar nursery currently forming an open cluster of stars.>> Image Credit: The Hubble Heritage Team, (STScI/AURA), ESA, NASA The electromagnetic spectrum λν=c, E=hν System Filter Wavelength Width Johnson- U 3600 Å 700 Å Morgan B 4400 Å 1000 Å V 5500 Å 900 Å Infrared R 7000 Å 2200 Å I 9000 Å 2400 Å J 1.22 µm 0.26 µm H 1.65 µm 0.29 µm K 2.18 µm 0.41 µm L 3.55 µm 0.57 µm M 4.77 µm 0.45 µm N 10.5 µm 5.2 µm Q 20.1 µm 7.8 µm

4 SOFIA

5 Arecibo Radio Telescope Sites of star formation Andromeda seen in the optical (Hubble Space Telescope)

6 Sites of star formation Andromeda seen in the infrared (Herschel Space Observatory)

7 Molecular Clouds - the Milky Way as seen in carbon monoxide (CO) Dame, Hartmann & Thaddeus 2001, ApJ, 547,792 A portion of the Northern sky. The Milky Way is depicted as light grey, while the darker patches indicate giant molecular clouds. Also shown, according to their relative brightness, are the more prominent stars, along principle constellation.

8 Molecular Gas and Stellar Nurseries Ophiuchus Taurus-Auriga Orion The Orion Nebula and the Trapezium Cluster Central number density of stars: 10 4 pc -3!! See also:

9 A star-forming region Zoom in M16 (eagle) Milky Way M17 (horseshoe) M8 (Lagoon) Jupiter A starforming region

10 A starforming region Eagle Nebula (M16) A starforming region Eagle Nebula (M16)

11 A star-forming region Size of our Solar System Eagle Nebula (M16) The power of the infrared

12 The power of the infrared The power of the infrared

13 The power of the infrared Outflows and jets

14 Circumstellar (protoplanetary) discs Circumstellar (protoplanetary) discs: accretion and ouflow

15 The Physics of Star Formation A complicated, nonlinear process: - Gravity vs pressure (thermal, magnetic, turbulence, radiation, cosmic rays) and shear. - Heating and cooling, generation and decay of turbulence, generation (dynamo) and diffusion of B-fields. - Chemical evolution of dust and gas. - Stellar structure and evolution - Feedback - Wide range of scales (~12 dex in space, time) and multidimensional. - Uncertain/unconstrained initial conditions/boundary conditions. Complete theory of star formation Analytic theory Observations Numerical models Standard theory of isolated low-mass star formation Shu, Adams, Lizano (1987) Many observed examples of this for low-mass star formation. Starless Core Protostellar Core Protoplanetary Disk CFHT/Cuillandre NASA/JPL/Tobin NASA/McCaughrean/OʼDell But it is not clear if this simple theory holds for all star-forming environments and for the formation of massive stars.

16 Exoplanets Planets: where do they form?

17 Planets form in circumstellar disks Artist impression of planet formation