topics for "regular" class meetings (10):

  1.  Main sequence of stars (I)
       Hertsprung or Russell paper

  2.  Main sequence of stars (II): 
       Gaia DR1 or DR3 paper
          https://www.aanda.org/articles/aa/full_html/2018/08/aa32843-18/aa32843-18.html

  3.  Rotation curves and dark matter
       Rubin and Ford paper
            https://ui.adsabs.harvard.edu/abs/1980ApJ...238..471R/abstract


  4.  Distance-velocity relationship (I)
       Hubble paper, and later as well, maybe SBF Tonry?

  5.  Modern H-nought result using Cepheids in one galaxy (II)
       Freedman group paper

  6.  LRD (I): discovery 

  7.  LRD (II): possible explanation with "black hole stars"
       https://www.nature.com/articles/s41586-026-10846-4

  8.  Exoplanets (I): discover-ies
       Pulsar paper, 51 Peg paper
           https://web.archive.org/web/20110720034147/http://www2.astro.psu.edu/~niel/astro550/week07-wolszczan-pulsar-planets.pdf
           https://ui.adsabs.harvard.edu/abs/1995Natur.378..355M/abstract

  9.  Exoplanets (II): evidence for atmosphere
       recent papers on LHS 1140b
           https://arxiv.org/abs/1704.05556
           https://arxiv.org/abs/2607.14326

 10.