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Published February 2010 | Published
Journal Article Open

F, G, K, M Spectral Standards in the Y Band (0.95-1.11 μm)


We take advantage of good atmospheric transparency and the availability of high-quality instrumentation in the 1 μm near-infrared atmospheric window to present a grid of F, G, K, and M spectral standards observed at high spectral resolution (R ≈ 25,000). In addition to a spectral atlas, we present a catalog of atomic line absorption features in the 0.95-1.11 μm range. The catalog includes a wide range of line excitation potentials, from 0-13 eV, arising from neutral and singly ionized species, most frequently those of Fe I and Ti I at low excitation, Cr I, Fe I, and Si I at moderate excitation, and C I, S I, and Si I having relatively high excitation. The spectra also include several prominent molecular bands from CN and FeH. For the atomic species, we analyze trends in the excitation potential, line depth, and equivalent width across the grid of spectroscopic standards to identify temperature and surface gravity diagnostics near 1 μm. We identify the line ratios that appear especially useful for spectral typing as those involving Ti I and C I or S I, which are temperature sensitive in opposite directions, and Sr II, which is gravity sensitive at all spectral types. ASCII versions of all spectra are available in the online version of the journal.

Additional Information

© 2010 American Astronomical Society. Print publication: Issue 2 (2010 February); received 2009 August 20; accepted for publication 2009 November 9; published 2010 January 14. We thank the anonymous referee for his/her careful inspection of the manuscript. We acknowledge with gratitude the builders of NIRSPEC and the hard work and assistance from the staff at the W. M. Keck Observatory. The observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some of the spectra presented herein were obtained by Dan Stark and Richard Ellis or Colette Salyk and Geoff Blake; we are grateful for their contributions. We consulted The Atomic Line List (http://www.pa.uky.edu/∼peter/atomic/) and the CfA Kurucz line list (http://cfa-www.harvard.edu/amp/ampdata/kurucz23/ sekur.html) while conducting this research. We are grateful to Andrew Baker for his tolerance during the final analysis and writing stages of this paper.

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