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APS » Journals » Phys. Rev. Lett. » Volume 89 » Issue 28
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Phys. Rev. Lett. 89, 281101 (2002) [4 pages]

Determination of Hyperfine-Induced Transition Rates from Observations of a Planetary Nebula

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Tomas Brage
Department of Physics, Lund University, Box 118, S-221 00 Lund, Sweden

Philip G. Judge
High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, Colorado 80307-3000

Charles R. Proffitt
Science Programs, Computer Sciences Corporation, 3700 San Martin Drive, Baltimore, Maryland 21218

Received 2 July 2002; published 26 December 2002

Observations of the planetary nebula NGC3918 made with the STIS instrument on the Hubble Space Telescope reveal the first unambiguous detection of a hyperfine-induced transition 2s2p 3P0o→2s2 1S0 in the berylliumlike emission line spectrum of N IV at 1487.89 Å. A nebular model allows us to confirm a transition rate of 4×10-4   sec⁡-1±33% for this line. The measurement represents the first independent confirmation of the transition rate of hyperfine-induced lines in low ionization stages, and it provides support for the techniques used to compute these transitions for the determination of very low densities and isotope ratios.

© 2002 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.89.281101
DOI:
10.1103/PhysRevLett.89.281101
PACS:
95.30.Ky, 98.58.Li

*The National Center for Atmospheric Research is sponsored by the National Science Foundation.

†Also, The Space Telescope Science Institute, and the Institute for Astrophysics and Computational Science at the Catholic University of America.

 
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