Publications of the Astronomical Society of the Pacific Vol.106 1894 January No. 695 Publications of the Astronomical Society of the Pacific 106: 1-24, 1994 January Invited Review Paper Astrophysics in 1993 Virginia Trimble 1 and Peter J. T. Leonard 2 Astronomy Department, University of Maryland, College Park, Maryland 20742 Received 1993 October 8; accepted 1993 October 22 ABSTRACT. After the astronomical excitements of 1991 and 1992, 1993 was frankly a bit of a letdown. More papers by more people were submitted and published than ever before (and this review has twice as many authors as the previous ones). Nevertheless, there seem to have been fewer large, definitive steps. As a result, we have focused on a handful of broad terrains for which the maps have improved, including stellar rotation and mass loss, dynamics of globular clusters, and quasar absorption lines, but have also highlighted many more of the small steps by which astronomy advances toward inventorying and understanding the universe. As a consequence, the ordering of topics is less obviously from near to far than in 1991 and 1992. And the potential for misattributions and unjustifiable neglect is probably somewhat larger. 1. INTRODUCTION In accordance with a principle enunciated in Astro- physics in 1992 (PASP 105, 1, cited as Ap92 hereafter), writing the third article in the series has created a well- known class of astrophysical object. The characteristics of the class have not yet been fully defined, but clearly include some level of arbitrariness and a certain breathless excite- ment, bom of envy and the mad chase to keep up with the contributions of so many productive colleagues. Ap92 attracted more, but also kinder, feedback than Ap91 (PASP 104, 1), much of it from authors generously reapportioning part of the credit given to them. Some of these inputs are mentioned in Sec. 12 {Addenda et Corri- genda), The ground rules remain much the same. No fine tuning of topics addressed in Ap91 or Ap92. Papers by the present authors can be cited as background or as strawpersons, but are, by fiat, not among the highlights of the year. The set of journals regularly scanned now includes Nature, Physical Review Letters, Science, Astrophysical Journal (plus Letters and Supplements), Monthly Notices, Astronomy and Astro- physics (plus Supplements and Reviews), Astrophysics and Space Science, Astronomical Journal, Astrofizica, Acta As- tronomica, Soviet Astronomy and Letters (now renamed Astronomy Reports and Astronomy Letters, somewhat un- fortunate choices). Astronomische Nachrichten, Journal of ^Iso Physics Department, University of California, Irvine, CA 92717. Work done at T-Division, Los Alamos National Laboratory, Los Alamos, NM 87545. Astrophysics and Astronomy, Publications of the Astronom- ical Society of Japan, Astrophysical Letters and Communi- cations, Baltic Astronomy, I AU Circulars, and (it goes without saying) Publications of the Astronomical Society of the Pacific. Items appearing elsewhere have been caught by chance or were sought out as background material. The reference year includes journals reaching our library shelves between 1 October 1992 and 30 September 1993. There is no use pretending that the two authors have similar writing styles or even always similar opinions on what is important. Thus you probably won't need to be told that P.J.T.L wrote Sec. 6 and contributed some of the items in Sees. 2, 5, 7, 8, 9, 10, while V.T. is responsible for the rest. 2. DEATHS IN THE FAMILY Past a certain ^ge, most people read the New York Times backwards ftam the obituary page. We have tried to make this easy for you, but, in addition, many of the events are local, on scales from a few meters to a few parsecs. 2.1 The 17 keV Neutrino Cosmologists had still not quite decided whether having an unstable neutrino with a rest mass of 17 keV in the early universe would be good or bad for galaxy formation, when it ceased to matter. From the first reports of laboratory evidence for a such a particle a couple of years ago, exper- imental physicists had been divided into camps pro (mostly using solid-state particle detectors) and con (mostly using gas-filled detectors). Evidence for the parti- © 1994. Astronomical Society of the Pacific © Astronomical Society of the Pacific · Provided by the NASA Astrophysics Data System