= Protostars And Planets = ------- === Volume 6, 2014 952p === . On order from Amazon === Volume 5, 2007 951p === . PSU QB806.P78 . [[ http://www.ifa.hawaii.edu/users/jpw/ism/reading/lada_extinction_mapping.pdf | Ch1: Near-Infrared Extinction and Molecular Cloud Structure, Charles J. Lada ]] . p3 10K does not excite H,,2,, lowest energy rotational transitions in mid-IR . p4 2448 dark clouds 6 and 18 arcminutes ref: 2005 Dobashi K., Uehara H. ''Publ. Astr. Soc. Japan, 57 1-368'' . p7 Fig 2 [[https://en.wikipedia.org/wiki/Barnard_68|Barnard 68 cloud]] about 200 arcseconds across, maybe 20K as^2^, 100 AU/as . 2 solar masses, 0.15? pc across . sky is (4/π)(360*3600)^2& as^2^, 2.138e12 as^2^ . [[ http://www.dvaa.org/AData/Barnard.html | E. E. Barnard's Catalog of Dark Nebulae ]] diameters in arcseconds, "UM2 Pg" is page number in Uranometria, early 1600s 418K am^2^ -> 1.5e9 as^2^ -> 700 ppm of sky, assume 2/3 are missing, 0.2% === Volume 4, 2000 1422p === === Volume 3, 1993 1596p === === Volume 2. 1985 1293p === === Volume 1, 1978 756p === ------ . CMF: Core Mass Function . IMF: Initial Mass Function . ISM: InterStellar Medium