Spectrum of the star BD -00^o3227 provided by S. Howell (National Optical Astronomy Observatories)

PHYS 6980/8980 Special Topics (Stellar Spectra)

• Syllabus for course, Draft 1 (40kb)
• Syllabus for course, Draft 3 (48kb, 1/18/06). Draft 2 was distributed on paper and will not be reproduced here.
• Homework Assignment 1 (68kb) due Friday, February 10. The files needed for this assignment can be found through MyUT under "My Consolidated Courses" in "My Courses."
• Homework Assignment 2 (40kb) due Friday, March 3. The files needed for this assignment can be found through MyUT under "My Consolidated Courses" in "My Courses."

  Revised instructions for Homework 2:

  The problem is that the Rayleigh-Jeans approximation is not good enough at 7000 Å for this purpose.

  In mk1dspec, specify a starting wavelength of 100000 Å (10 microns) and an ending wavelength of 1000 Å. It's OK to have the wavelength scale backwards. Using the Rayleigh-Jeans approximation, calculate the flux at 100000 Å and put that value in the parameter list of mk1dspec for the flux at the first pixel. Then no further scaling of the black body curve will be necessary.

  There will be no change in the due date for the assignment.

• The schedule of student presentations is posted under "News" in the course page on MyUT.

Links related to the term project

• NASA Astrophysics Data System (ADS)
  Search the astronomical research literature by keyword, author, etc.
• Simbad Astronomical Database Query Page
  Look up information about any star from the primary research literature
• The Ritter Observatory Archive
  Index to all reduced Ritter spectra. To access the data themselves:
  • Log into your account on astro1
  • Access the path: /mnt/vol01/ritter/Reduced/archive
  • Copy the desired file(s) to your account
• The Ritter Observatory Public Archive
  Contains a subset (continually growing) of all Ritter reduced data. If the spectrum you want happens to be here, you can download it directly without logging in to astro1.
• Libraries of stellar spectra - a voluminous and possibly complete listing of databases of observed and synthetic spectra
• Multimission Archive at Space Telescope - Includes data archives for FUSE, IUE, and other NASA missions
• More to come; updates in progress ...

Materials shown in class, most recent first

Friday, April 28:

• Modeling the energy distributions of T Tauri stars: Figure 10 from Basri, G. and Bertout, C. 1989, Astrophys. J., 341, 340
• Comparison between the Balmer line widths in a DA white dwarf and in normal A-type main-sequence stars: A Digital Spectral Classification Atlas by R. O. Gray, montage from no. 11 and the top spectrum of no. 32
• Balmer line profile fits in DA white dwarfs, Figure 4 from Bergeron et al. 1992, Astrophys. J., 394, 228
• Line profile fits in DB white dwarfs, Figures 4 and 10 from Dreizler and Werner 1996, Astron. Astrophys., 314, 217
• Line profile fits in FUSE spectra of DB white dwarfs, Figures 6, 7, and 9 from Petitclerc et al. 2005, Astrophys. J., 624, 317
• Information on alternative careers for people with degrees in astronomy: first in a series of four cartoons by J. A. Eddy, which appeared in Mercury, the magazine of the Astronomical Society of the Pacific, 1980 March-April and July-August issues

Wednesday, April 26:

• The current star formation paradigm: cartoon figure from the University of Colorado (scroll a bit more than halfway down the page to the figure)
• Four young stellar objects with dusty disks (from Hubble Space Telescope)
• Montage of spectra of T Tauri stars of various activity levels, from Bertout, C. 1989, Ann. Rev. Astron. Astrophys., 27, 351
• High-resolution spectrum of DR Tauri, an extreme T Tauri star: selected panels from Figure 1 and 2 of Appenzeller, I. et al. 1988, Publ. Astron. Soc. Pacific, 100, 815
• Blue-shifted forbidden line components, Figure 1 from Edwards, S. et al. 1987, Astrophys. J., 321, 473

Monday, April 24: Example infrared spectral energy distributions from young stellar objects: Figures 3e, 3c, and 3a from Wilking, B. A., Lada, C. J., and Young, E T. 1989, Astrophys. J., 340, 823

Friday, April 21

• Optical (Figure 6) and infrared (Figure 10) observational and synthetic spectra from Houdashelt, M. L. et al. 2000, Astron. J., 119, 1424
• Spectra of an S star and a marginal S star from A Digital Spectral Classification Atlas by R. O. Gray, no. 31
• A technetium feature in the spectra of S stars: Van Eck, S. and Jorissen, A. 1999, Astron. Astrophys., 345, 127
• Structure of the central regions of an asymptotic giant branch star, showing nuclear reactions relevant to the s-process, from Iben, I. 1991, Astrophys. J. Supp. Ser., 76, 55

Monday, April 10: Here is an authoritative guide to constellation names and how they are used (possessive form) with star names. No pronunciation guide, though.

Friday, April 7: M star frames from A Digital Spectral Classification Atlas by R. O. Gray, nos. 24, 25, and 26.

Friday, March 31

• The dividing line in the H-R diagram between stars with and without transition region plasma, as seen in C IV λ1549, Figure 3 from Simon, T. 1986, Astrophys. Sp. Sci., 118, 209
• The "K4" component (Reimers, D. 1977, Astron. Astrophys., 57, 395), evidence for mass loss, in the K giant star θ Her. Data from Library of high and mid-resolution spectra

• The dividing line in the H-R diagram between cool giant stars with and without cool winds: Figure 1 from Stencel, R. E. and Mullan, D. J. 1980, Astrophys. J.,238, 221. This dividing line is in more or less the same place as the previous one.
• The Doppler shift of the "K4" component as a function of position in the H-R diagram, Figure 4 from Reimers, D. 1977, Astron. Astrophys., 57, 395. Again the dividing line between stars with and without mass loss is in more or less the same place as previously.

Wednesday, March 29

• A Digital Spectral Classification Atlas by R. O. Gray, nos. 21 and 23; G band temperature effect and Ca II K luminosity effect revisited
• Paper explaining the behavior of the G band in K-type stars: Bell, R. A. and Tripicco, M. J. 1991, Astron. J., 102, 777
• Figure 3 from Lutz, T. E., Furenlid, I., and Lutz, J. H. 1973, Astrophys. J., 184, 787 illustrating the luminosity effect in Ca II K
• Figures 2, 3, and 7 from Pace et al. 2003, Astron. Astrophys., 401, 997, showing the calibration of the Wilson-Bappu Effect and its dependence on [Fe/H]
• Paper giving explanation of Wilson-Bappu Effect: Ayres, T. R. 1979, Astrophys. J., 228, 509
• Figure 1 from Linsky, J. L. and Haisch, B. M. 1979, Astrophys. J., 229, L27, showing the ultraviolet spectra of stars with chromospheres but with and without hot, transition region-temperature plasma

Monday, March 27

• Figure 1, right, from Vaughan, A. H. et al. 1981, Astrophys. J., 250, 276 illustrating rotational modulation of Ca II H and K line core fluxes
• Figure 4 from Noyes, R. W. et al. 1984, Astrophys. J., 279, 763 illustrating the dependence of Ca II H and K flux (corrected for photospheric contribution) on stellar rotation period
• Figure 3 from Soderblom, D. R., Duncan, D. K., and Johnson, D. R. H. 1991, Astrophys. J., 375, 722 illustrating the dependence of Ca II H and K line flux on stellar age
• Figures 2 and 4 from Petit, P. et al. 2005, Mon. Not. Roy. Astron. Soc., 361, 837, showing the mean line profile and circular polarization line profile and the derived magnetic field in the active-chromosphere star ξ Boo A
• A Digital Spectral Classification Atlas by R. O. Gray, nos. 21 and 24

Friday, March 24

• Information on measurement of solar magnetic fields with SOHO from Scherrer, P. H. et al. 1995, Solar Physics, 162, 129
• K-line picture of the Sun taken on 28 January 1998 from the Mees Solar Observatory archives showing the chromospheric network
• He II λ304 picture of the Sun from SOHO (see "Best of SOHO"), also showing the chromospheric network
• Figures 2 and 3 from Lawrence, J. K. et al. 2003, Astrophys. J., 597, 1178 showing detailed correspondence in space and time between K line brightness and magnetic field strength on the Sun
• Figure 1 from Ulmschneider, P. et al. 2001, Astrophys. J., 559, L167 showing range of Ca II H and K activity in late-type dwarf stars and agreement with two-component heating model

Wednesday, March 22

• Representative set of Mg II emission cores, Figures 2c and 2d from Hartmann, L., Dupree, A. K., and Raymond, J. C. 1982, Astrophys. J., 252, 214
• Ultraviolet emission-line spectra, Figures 1 and 2 from Ayres, T. R., Marstad, N. C., and Linsky, J. L. 1981, Astrophys. J., 247, 545
• The Sun at various wavelengths, Figure 4 from M. J. Aschwanden, A. Poland, and D. M. Rabin, "The New Solar Corona," Ann. Revs. Astron. Astrophys., 39, 175 (Original figure is in MyUT Photos section)
• Collisional ionization equilibria; most abundant ion as a function of temperature; see tables at end of paper Arnaud, M. and Rothenflug, R. 1985, Astron. Astrophys. Supp. Ser., 60, 425 (item added to page 4/1/06)

Monday, March 20

• A Digital Spectral Classification Atlas by R. O. Gray, nos. 21, 22, and 23
• Chromospheric features in ξ Boo A (G8 V) - data from "Library of high and mid-resolution spectra ... " (right click on image to see larger version)

Ca II H and K	Hα

• Ca II K in the Sun - data from BASS2000 (BAse de données Solaires Sol 2000)

Wide View	Narrow View

• Partial Grotrian diagrams for Ca II and Mg II - see Photos section of MyUT
• Mg II in ξ Boo A (G8 V) - data from MAST IUE

Wide View	Narrow View

Friday, March 17

• Li abundances in open clusters as a function of age, Boesgaard, A. M. 1991, Astrophys. J., 370, L95, Fig. 2
• Example of meridional circulation pattern, Tassoul, J.-L. and Tassoul, M. 1982, Astrophys. J. Suppl. Ser., 49, 317
• Observational data relevant to the Li dip (vertical line added by me) from Talon, S. and Charbonnel, C. 1998, Astron. Astrophys., 335, 959, Fig. 1
• Mass in the convective zone as a function of T_eff, from Talon and Charbonnel 1998 op. cit., Fig. 2

Wednesday, March 15

• A Digital Spectral Classification Atlas by R. O. Gray, nos. 17, 18, and 19
• Kawaler, S. D. 1987, Publ. Astr. Soc. Pacific, 99, 1322 Fig. 1 (version marked up by me will be posted in MyUT)
• Wolff, S. C. and Simon, T. 1997, Publ. Astr. Soc. Pacific, 109, 759 Fig. 3b
• Boesgaard, A. M. and Tripicco, M. J. 1986, Astrophys. J., 302, L49, Fig. 1
• Boesgaard, A. M. 1991, Astrophys. J., 370, L95, Fig. 1

Monday, March 13

• General information: Lamers, H. J. G. L. M. and Cassinelli, J. P. 1999, Introduction to Stellar Winds (Cambridge U. Press)
• Ultraviolet C IV and N V P Cygni line profiles from Walborn, N. R. and Panek, R. J. 1984, Astrophys. J., 286, 718
• Wind driving lines in the stellar energy distribution: Abbott, D. C. 1982, Astrophys. J., 259, 282

Friday, March 3

• O star spectral energy distributions: Figure 2a and 2r from Jacoby, G. H., Hunter, D. A., and Christian, C. A. 1984, ApJS, 56, 257
• Ultraviolet C IV P Cygni line profiles from Walborn, N. R. and Panek, R. J. 1984, Astrophys. J., 286, 718

Wednesday, March 1

• Explanation for N III λλ4634-4640 emission in O((f)) stars, including term diagram for N⁺⁺: Mihalas, D. 1973, Publ. Astr. Soc. Pacific, 85, 593
• Discussion of C III λ5696 emission: Leparskas, H. J. A. and Marlborough, J. M. 1979, Publ. Astr. Soc. Pacific, 91, 101
• Non-LTE effects in H and He II: Auer, L. H. and Mihalas, D. 1972, Ap. J. Suppl. Ser., 24, 193

Monday, February 27

• A Digital Spectral Classification Atlas by R. O. Gray, nos. 2. 4, and 5
• Walborn, N. R. et al. 2002, The Astronomical Journal, 123, 2754

Friday, February 24

• He I λ4471 in the spectrum of τ Scorpii (B0V):

• Figure 1 from Mihalas, D., Barnard, A. J., Cooper, J., and Smith, E. W. 1974, Astrophys. J., 190, 315-318
• Figures 5-7 from Auer, L. H. and Mihalas, D. 1973, Astrophys. J. Suppl Ser., 25, 433
• Bottom right panel from Figure 1a of Leone, F. and Lanzafame, A. C. 1998, A&A, 330, 306

Monday, February 13, and Wednesday, February 15

• More from A Digital Spectral Classification Atlas by R. O. Gray: nos. 11, 12, 6, 10, and 7
• Energy distributions of B-type main-sequence stars: Fig. 2b from Jacoby et al. (see citation below). The figures from Jacoby et al. are now posted in the Photos section of MyUT.

Friday, February 10, new items:

• Figure 2c from Jacoby, G. H., Hunter, D. A., and Christian, C. A. 1984, ApJS, 56, 257
• Table 5 from Matsushima 1969, ApJ, 158, 1137

Wednesday, February 8:

Monday, February 6:

• Figures 2 and 5 from Bertone et al. 2004, AJ, 128, 829
• Graph showing UBV filter response functions with the energy distribution of a star.
• Energy distribution from Jacoby, G. H., Hunter, D. A., and Christian, C. A. 1984, ApJS, 56, 257
• UBV response functions from Buser, R. and Kurucz, R. L. 1978, A&A, 70, 555

Monday, January 30: As examples of stellar spectral energy distributions, Fig. 1 from Code, Davis, Bless, and Hanbury Brown 1976, ApJ, 203, 417

Friday, January 27

• Jason Aufdenberg's evidence that Vega is a rapid rotator seen pole-on was presented at the 207th meeting of the AAS; abstract here. The details have been posted in MyUT.
• Comparison between a Lorentzian and a Gaussian line profile function; constants arbitrary (right click to enlarge)
  
  

Wednesday, January 25

Graph of the rotational broadening line profile function for a uniformly bright, spherical, rigidly rotating star.	Comparison between the Hα profiles of two A0V stars: the sharp-lined, apparently slowly rotating star α Lyrae (Vega); and the rapidly rotating star ζ Aquilae. The SIMBAD database gives several measured values for the latter star, all near 300 km s-1

Friday, January 20 - right click image (control click on the Mac) to view at full size

Comparison of two spectra of the same star (ο Aquilae, F8V) at very different spectral resolutions. The spectrum plotted in white was taken with the Ritter Low-Dispersion Spectrograph at a resolving power λ/Δ&lambda = 6,000; the one in red was taken with ELODIE at the Observatoire de Haute-Provence (France) at a resolving power of 42,000.

Procedure for estimation of signal-to-noise ratio in a spectrum of Deneb (α Cygni, A2Ia) taken with the Ritter échelle spectrograph. This screen was entered from splot by means of the f keystroke. Now that I look at it again, the line representing the fit to the continuum is too low in the right-hand half of the spectrum. It should go through the middle of the noise fluctuations. For this reason, the calculated rms may be too large.

Wednesday, January 18

• Example spectra from the Michigan HD Project: see links at bottom of that page
• A Digital Spectral Classification Atlas by R. O. Gray; I showed no. 19 and no. 21