NOTE: This page provides a very brief summary of the main topics covered during each class meeting. Refer to your (or your classmates') class notes for details. For homework assignments refer to the Course Assignments page.

Wednesday, Dec. 10, 11 AM - 1 PM : Final Exam, in our regular classroom (Rm 144-A).

Wednesday, Dec. 3 (#29): Last Class Day. Class wrap-up, final topics for discussion. Eddington and his legacy. Helioseismology. Einstein, the theory of relativity and its observational implications. Overview of final exam. "Make-up" class TBA: observing at the Highland Road Park Observatory!

Monday, Dec. 1 (#28): Conclusion of video (on pulsars, dark matter, string theory, and cosmology). The stellar structure equations (conclusion). Definition of the Eddington luminosity and its implications.

Thanksgiving Break, Nov. 27-28, No Classes.

Wednesday, Nov. 26 (#27): Handouts (HW #10) of excerpts of Einstein's papers on special relativity (E=mc^2) and general relativity (the curvature of light due to mass, the cosmological constant); for discussion in class next week. Pre-Thanksgiving video: "Mysteries of the Universe" (on relativity and quantum mechanics).

Monday, Nov. 24 (#26): Collect HW #9. Discussion of Einstein's general theory of relativity. Observational implications: gravitational lensing, dark matter.

Wednesday, Nov. 19 (#25): Visit by Dr. Steve Cranmer, Smithsonian Astrophysical Observatory. Presentations on summer research programs by M. Baham (SOHO/UVCS at SAO) and A. Pullen (QUIET at JPL). Discussion of solar astronomy and astrophysics.

Monday, Nov. 17 (#24): Equations of stellar structure (cont'd). Equation of hydrostatic equilibrium (condition for "neutral buoyancy" of a gas element inside a star); gravitational force inward exactly counter-balanced by radiation pressure outward. Pressure "Equation of State"; total pressure = sum of radiation pressure (from photons) and gas pressure (from particles). Definition of mean molecular weight.

Wednesday, Nov. 12 (#23): HW #9 assigned (due Monday, Nov. 24). Equations of stellar structure (cont'd). The equation of radiative transfer. Presentation of summer research project: M. Mbonye (MAXIM at the NASA/GSFC).

Monday, Nov. 10 (#22): Overview of the equations of stellar structure (hydrostatic, mass continuity, energy generation, and radiative (or convective) transfer of energy). Set of 4 coupled, non-linear, differential equations for pressure, mass, flux/luminosity, and temperature. Consideration of mass continuity and energy generation equations.

Wednesday, Nov. 5 (#21): Collect HW #8. Broadening mechanisms for spectral lines: natural vs Doppler vs collisional (pressure) broadening; relative importance of each. "Damping" profile = natural plus pressure broadening. "Voigt" profile = Doppler core with damping wings. Implications of narrow vs broad lines, development of cores and wings as function of column density, "saturation" of a spectral line. Notion of the "curve of growth" of a spectral line (equivalent width as a function of column density).

Monday, Nov. 3 (#20): Collect HW #7 (presentation abstracts). Solar flares on the Sun in progress (X-class flares!). The structure of spectral lines. The core vs the wings vs the continuum level. Definition of the equivalent width. Intro to line-broadening mechanisms: natural broadening and Doppler broadening.

Wednesday, Oct. 29 (#19): Handouts for HW #7 (due Mon., Nov. 3) and HW #8 (due Wed., Nov. 5) on oral/poster presentations. Discussion of main contributors to radiative opacity: electron scattering, free-free, bound-free, bound-bound absorption. Power-law approximation for opacity; Kramer's opacity law (for f-f absorption). Estimation of mfp of photons in the Sun (~1 cm); implications for escape of photons from the solar interior (a "random walk" process).

Monday, Oct. 27 (#18): Collect HW #6. Brief review of M-B, Boltzman, and Saha equations; observed vs predicted line strength; definition of mass fractions X (=H), Y (=He), and Z (="metals"). Intro to radiative transfer. Notion of opacity and opacity coefficient. The attenuation equation for radiation. Definition of column density, mean free path, e-folding distance (or scale height), optical depth. Optically "thin" vs optically "thick." Photosphere defined by tau=1.

Wednesday, Oct. 22 (#17): Dr. Stacy away again (at NASA/GSFC). Continue assigned readings and homework.

Monday, Oct. 20 (#16): Assigned HW #6 (due Monday, Oct. 27). Formation of spectral lines (cont'd). M-B, Boltzman, and Saha equations. Definition of statistical weights, partition functions, ionization potentials, etc. Observed line strengths due to a combination of Boltzman and Saha probabilities. Example: strength of Balmer H-alpha line along main sequence spectral types (strong temperature dependence). Compare with strength of Ca H and K lines in solar photosphere.

Wednesday, Oct. 15 (#15): Dr. Stacy away (at the Univ. of New Hampshire). Continue work on take-home computer lab assignment.

Monday, Oct. 13 (#14): "Take-home" Test (#2) handed out (CLEA computer lab on Spectral Classification). Returned Hourly Test #1 and discussed solutions. The formation of spectral lines. Intro to the Maxwell-Boltzman equation, the Boltzman equation, and the Saha equation.

Wednesday, Oct. 8 (#13): The spectral classification of stars. The Hertzsprung-Russell diagram in its various representations (observational vs theoretical). Defintion of spectral classes, luminosity classes, main sequence, "early" vs "late" spectral types, etc.

Monday, Oct. 6 (#12): Hourly Test #1

Wednesday, Oct. 1 (#11): Returned graded homework assignments with solutions. Review of homework problems. Discussion of topics for Hourly Test #1 and general format of test.

Monday, Sept. 29 (#10): Black-body radiation (summary, Kraus notes). Intro to spectral lines. Review of Kirchoff's laws. Continuous vs emission vs absorption spectra. Spectral lines from stars and spectral line profiles. Example of the solar spectrum (Fraunhofer lines, etc.). View examples of emission spectra in class: Hg, Na, etc. from gas-discharge tubes.

Wednesday, Sept. 24 (#9): HW #4 assigned. Due Monday, Sept. 29. Black-body radiation and the Planck black-body formula for bodies in thermal equilibrium. The Wien displacement law and the Stefan-Boltzman law. Bolometric luminosity and relation to the integrated black-body curve. The photometric filters (U, B, V, etc.) and their use in determining monochromatic flux/luminosity.

Monday, Sept. 22 (#8): Demise of the Galileo spacecraft (RIP). Binary stars (Chapt. 7). Categories: visual, astrometric, eclipsing, spectroscopic. Physical properties deduced from light curves and velocity curves. Determining the masses of binary stars. The mass function.

Wednesday, Sept. 17 (#7): Derivation of the distance modulus. Definition of stellar motions. Proper motion (arcsec/yr) and tangetial velocity. Radial velocity from Doppler shift observed in spectral lines. Total space velocity from vector sum. Non-relativistic vs relativistic Doppler effect. Definition of the redshift.

Monday, Sept. 15 (#6): HW #3 assigned. Due Monday, Sept. 22. The magnitude scale. Luminosity vs flux. Example of solar luminosity and the solar constant. Definition of absolute magnitude. Review of parallax and defintion of the parsec. Examples using tabular values for the nearest stars.

Wednesday, Sept. 10 (#5): Kepler's laws derived from Newton's laws of motion and gravitation. Center-of-mass coordinate systems. Bound orbits as examples of inertial frames of reference. True coefficient of Kepler's 3rd law (=1 when period in years and semi-major axis in AU).

Monday, Sept. 8 (#4): Example of IAUC 8188 on epsilon Indi B as a review of astronomical nomenclature. Notion of "brown dwarfs." Definition of proper motion, position angle (for binary stars). Angular separtion and distance yields true separation (application of small-angle formula). Astrometry vs photometry. Kepler's 3rd law. Log-log vs linear-linear plots. A straight line in a log-log plot implies a power-law relation between the variables plotted.

Wednesday, Sept. 3 (#3): HW #2 assigned. Due Monday, Sept. 15. More on orbital elements, nomenclature, and definitions (e.g., Julian date). Review of Kepler's laws of orbital motion.

Monday, Sept. 1: Labor Day Holiday. No class.

Wednesday, Aug. 27 (#2): HW #1 handed out. Due Wednesday, Sept. 3. Mars at opposition! Closest approach in 60 kyr! Mars as an example of orbital mechanics. Definition of orbital elements. Review of basic concepts: celestial sphere and coordinate systems, time, etc.

Monday, Aug. 25 (Class #1): Intro and overview; course information, textbook, syllabus, grading criteria, etc. Set meeting time: MW 1-2:20 PM in Room 144-A.

gstacy@phys.subr.edu