Hubble space telescope observations of cool white dwarf stars: Detection of new species of heavy elements

Harry Shipman, Maurice Barnhill, Judi Provencal, Scott Roby, Irmela Bues, France Cordova, Gordon Hammond, Paul Hintzen, Detlev Koester, James Liebert, Terry Oswalt, Sumner Starrfield, Gary Wegner, Volker Weidemann

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Observations of cool white dwarf stars with the Hubble Space Telescope has uncovered a number of spectral features from previously unobserved species. In this paper we present the data on four cool white dwarfs. We present line identifications, equivalent width measurements, and brief summaries of the significance of our findings. The four stars observed are GD 40 (DBZ3), G 74-7 (DAZ), L 745-46A (DZ), and LDS 749 B (DBA). Many additional species of heavy elements were detected in GD 40 and G 74-7. In L 745-46A,while the detections are limited to Fe I, Fe II, and Mg II, the quality of the Mg II h and k line profiles should permit a test of the line broadening theories, which are so crucial to abundance determinations. The clear detection of Mg II h and k in LDS 749 B should, once an abundance determination is made, provide a clear test of the hypothesis that the DBA stars are the result of accretion from the interstellar medium. This star contains no other clear features other than a tantalizing hint of C II 1335 with a P Cygni profile, and some expected He I lines.

Original languageEnglish (US)
Pages (from-to)1231-1238
Number of pages8
JournalAstronomical Journal
Issue number3
StatePublished - Mar 1995

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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