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Welcome to Astro 580! Instructor: Prof. Steven Kawaler |
From the course catalog:
Astro 580. Stellar Astrophysics. (3-0) Cr. 3. Prereq: 405 or 505.
Prereq: 405 or 505. The interior structure and atmospheric properties of stars: Stellar structure equations and constitutive relations: energy generation, energy transport by radiation and convection; equation of state, nuclear energy generation and nucleosynthesis. Numerical and analytic solutions to the equations of structure and evolution. Observational connections through the theory of radiative transfer. Line and continuum processes and sources of opacity. Non-LTE and statistical equilibrium. Line profiles. Interpretation of stellar spectra: temperature, pressure, and abundance determinations. Stellar evolution from formation to final phases.
We meet Tuesday and Thursday, 12:40-2:00 in a room to be named later
Current News
- Exam 3 has been graded, and the final course grades submitted. See Canvas for comments on your exams and to see all of your grades
- Thanks to all students for your patience through this unusual transition to virtual instruction.
- Please consult Canvas and this website as we have moved to remote instruction. We live in interesting times.
- Thursday's "Journal Stars" chat(s):
- April 30 (Suvadip): The Impact of White Dwarf Luminosity Profiles on Oscillation Frequencies
- April 23 (Drew): The Aarhus Red Giants Challenge I: Stellar structures in the red giant branch phase
- April 16 (Gwen): The Curious Case of the North Star: the continuing tension between evolution models and measurements of Polaris
- March 12 (Yue): Production of Lithium in Primordial Supernovae
- March 5 (Joseph): A Massive Star's Dying Breaths: Pulsating Red Supergiants and Their Resulting Type IIP Supernovae
- February 27 (David): The Uncertain Masses of Progenitors of Core Collapse Supernovae and Direct Collapse Black Holes
- February 13 (Yussef): Type Ia supernovae from non-accreting progenitors
- February 5 (Shujaut): A k-ω model for turbulent convection in stars
- January 30 (Matt): Evidence of Spectral Evolution on the white dwarf sample from the Gaia Mission
- January 23 (Kiley): The Featureless Transmission Spectra of Two Super-Puff Planets
- January 21 (Steve - demo): Correlated Depletion and Dilution of Lithium and Beryllium Revealed by Subgiants in M 67
Past News
- Exam 3 was made available on Canvas on Thursday, 4/30 and was due by 5:00pm on Monday, May 3.
- Final grading formula has been amended - Exam 3 is now worth the same as Exams 1 and 2 (20% of the course grade each). An additional 10% has been added to the Homework category, with all segment quizzes combining to be worth a single HW and added into the HW category.
- Reading, Week of April 27
- Bohm-Vitense, Chapter 13
- HK&T, Chapter 8 (asteroseismology)
- Asteroseismology notes
- Reading, Week of April 20
- Bohm Vitense, Chapters 10-13
- Projects were due on Friday, May 1, 2020
Project paper: Paper choices (a paper published in a refereed journal within the last 2-3 years) should have be decided on by Thursday, April 9
Information on the MESA project is here for a tool to help with your project. Or if you prefer to see a narrative about the MESA project, go here for the first paper describing it.- The written format of your final project should be in the form of a referee report on your chosen paper. To help see what you might produce, please have a look at the following::
- Here is a sample paper, as submitted
- Here is the referee report on the paper
- ... and if you are interested, here is the final version.
- The written format of your final project should be in the form of a referee report on your chosen paper. To help see what you might produce, please have a look at the following::
- Reading, Week of April 13
- Bohm Vitense, Chapters 8-9
- Reading, Week of April 6
- Bohm-Vitense, Chapters 5-8
- With your newfound expertise in numerical solutions of ODEs, in your spare time have a look at how those same techniques are used in epidemiology modeling (the SIR method and its siblings):
- Notes by James Jones at Stanford
- Here's a Python implementation.
- Similar models are being used for Iowa and other states at this site
- Exam 2: Take home exam over the April 3-6 weekend
- Reading, week of March 30
- Bohm-Vitense, Chapters 1-5
- Problem Set 4: due March 26
- HK&T 7.2, 7.4, 7.6; bonus 7.1
- Henyey relaxation example - a perturbed solar model
- Some polytrope profiles as shown in class on March 12
- The Canvas home of Astro 580 is now up - you've been enrolled. Our virtual class will use Canvas for discussion and some document/video delivery. Stay tuned!
- Reading, week of March 9
- Winget et al. paper on neutrino emission in white dwarfs
- HK&T Chapter 7, through 7.2.3 and then 7.3
- L&L Chapter 10 and 11
- Problem Set 3: was due March 10
- L&L, 8.1
- HK&T, 6.6, 6.8; bonus 6.9
- Slides shown in class on C12(a,g)O16, and on the s- and r- process
- An interactive chart of nuclides showing the valley of beta stability
- Online access to nuclear reaction rates. See here for more.
- Reading, week of March 2
- HKT: Complete Chapter 6, start Chapter 7
- L&L: Chapter 8, Sect. 8.9
- Winget et al. paper on neutrino emission in white dwarfs
- Truran's review of nucleosynthesis in stars; in particular pages 68-71 ond 81-87 on the s- and r- process
- Reading, week of February 17, 24:
- HKT: Chapter 6
- L&L: Chapter 8
- EXAM 1: was available on February 21; and due on MONDAY, February 24 by 4:10 in my mailbox in 12 Physics. Because of the exam there was no class meeting on Thursday, February 20.
- Real convection (simulations and observations)
- Article by Iglesias and Rogers on the OPAL opacity calculations
- Slides about EOS and opacities
- From HW2, Here is a Jupyter notebook with a solution to HKT3.1. You'll see that I didn't use fsolve or any fancy scipy bits... just a simple Newton's method solution of the cubic equation. Just a bit of care taken to ensure that we find the right root. This avoids the dangers of using a 'black box' that doesn't do what you think/want it to do.
- Problem Set 2 was due February 11
- HK&T 3.1, 3.4, 3.9; L&L 4.5 - bonus, try HKT 3.3
NOTE: code for 3.9 can be found here:- Here is FORTRAN source geteos.f
- Executable version (Maco OS X). Right click on the link and download as a binary file 'geteos'.
- Prefer Python? here's a link to a .py file that has the subroutine and a rudimentary driver.
- Here is a Windoze .exe file (geteos.exe) - again right click to download as geteos.exe. Not sure if that one even works!
- Please come see me if you can't get any of these to work.
- HK&T 3.1, 3.4, 3.9; L&L 4.5 - bonus, try HKT 3.3
- Reading, week of February 9:
- HK&T, Chapter 5
- L&L, Chapter 7
- Reading, week of February 2
- HK&T, Chapter 4, 5
- L&L, Chapter 5-7
- Reading, week of January 27
- HK&T, Chapter 3
- L&L, Chapter 4
- Homology in the literature:
- Kawaler (1987): a paper on the initial angular momenta of stars
- Slinky demo of gravitational time scale
- Problem Set 1: was due January 28
- L&L, Problem 3.2, and for a bonus, 3.6
- HKT, Problems 1.2, 1.4, 1.6, and 1.9
- Be sure to obtain the eBook for the second required textbook for the class (Lamers and Levesque). You can download it from any computer directly connected to the iastate.edu network through Parks Library.
- Reading, the week of January 13, 20:
- Iben, Review of stellar evolution
- HK&T, Chapter 1
- L&L, Chapter 1&2 (they're short), 3
Web materials and resources for class
- Here is the cumulative assignment list.
- Here's the course syllabus
- Stellar evolution and stellar atmosphere "theory" is mostly numerical experimentation using more-or-less standard modeling codes. We will make extensive use of stellar strucure, evolution, (and perhaps atmosphere) codes that run on almost any modern computer (Linux PCs and Macs). One that is now becoming an 'industry standard' is MESA MESA installation is now easy on any Unix system (especially OSX on Macs), and running it is relatively easy after you make it up the somewhat steep learning curve.
As soon as possible, you should try to install and run MESA on a computer that is readily available to you. Almost any Mac or Linux laptop is sufficient - Windows is problematic. We may try to install MESA on one or more of the MacLab computers If you'd like to get a head start (a good idea!):
- MESA: Getting Started
- The MESA Marketplace is a growing site with lots of useful nuggets
- The MESA SDK: an essential piece for your installation.
- The MESA Bible, Old Testament
- The MESA Bible, New Testament
- MESA-Web: Not really cheating, but a web-based interface to MESA allowing you to compute stellar models and evolution tracks on the WWW.
Resources: Journals
As graduate students, you should be able to read the 'technical' literature of any physical science and at least glean some things of interest (assuming you can get through the jargon of the field). To that end, here are links to the main journals of astronomy - have a glance occasionally at the current online journals to see how the field is doing! All are available from ISU-based computers via the WWW.
- The Astrophysical Journal - the premier journal of astrophysics. Papers in the "ApJ" can be purely theoretical, or purely observational, but most lie somewhere in between. The "ApJ" consists of three separate publications: the main Journal, the ApJ Letters which are short papers of high interest that get published rapidly, and the ApJ Supplement which contains longer papers (frequently catalogs and other reference papers). In addtion, the ApJ publishes occasional CD-ROMs as part of the Supplement.
- The Astronomical Journal - the premier journal of observational astronomy. "AJ" papers concentrate on observations, with limited interpretation, but there is no hard and fast rule.
- Astronomy and Astrophysics - another top journal, concentrating on European research (though I publish there because there are no page charges!). The Europeans have it right - no distinction between astronomy and astrophysics - it is all there. Includes a 'Letters' section that contains short papers with rapid turnaround within the same covers. Much more material on stellar astrophysics than the ApJ.
- Monthly Notices of the Royal Astronomical Society - the main journal for British astronomy, it also publishes papers from astronomers around the world. A top journal.
- Annual Reviews of Astronomy and Astrophysics - authoritative reviews from experts in a wide variety of subjects - uniformly excellent papers, and a good "first place to go" when exploring a new field within astronomy.
- Other Journals - other smaller journals are more specialized in topic or approach. For example, Publications of the Astronomical Society of the Pacific (or PASP) has frequent papers on astronmical instrumentation, and dissertation abstracts. Icarus is the premier journal for solar system/planetary astronomy. Nature, Science, and Scientific American frequently have important astrophysics papers of broad interest. Etc., etc.
- Online access to the literature- In addition to the above journal links, most of the literature is available for indexed searches by author, keyword, and object via the NASA Astrophysics Data Service - an incredibly useful resource that I use at least 5 times a day.
- Preprints - There is a heavily used Preprint Server through arXiv.org - nearly all astronomy preprints are posted there before publication. Also well indexed. Selected papers are also discussed in the Astrobites site
Consider a 
Need to send me e-mail? Try my e-mail address: sdk@iastate.edu
