• DOI:10.1088/2041-8205/787/2/L16
• Corpus ID: 119195812

A LABORATORY log(gf) MEASUREMENT OF THE Ti ii 15873.84 Å H-BAND LINE IN SUPPORT OF SDSS-III APOGEE

@article{Wood2014ALL,
  title={A LABORATORY log(gf) MEASUREMENT OF THE Ti ii 15873.84 {\AA} H-BAND LINE IN SUPPORT OF SDSS-III APOGEE},
  author={Michael P. Wood and James E. Lawler and Matthew D. Shetrone},
  journal={The Astrophysical Journal Letters},
  year={2014},
  volume={787}
}

• M. P. Wood, J. Lawler, M. Shetrone
• Published 23 April 2014
• Physics
• The Astrophysical Journal Letters

The SDSS-III APOGEE collaboration has identified a single useable line in the H-band spectra of APOGEE target stars arising from a singly ionized species. This line of Ti ii (λair = 15873.84 Å) is therefore of great importance for use in stellar surface gravity, or log(g), determinations via the Saha equation. While a theoretical estimate of the line strength exists, to date no laboratory measurement of the line strength has been reported. Herein we report an absolute laboratory transition probability measurement for this important Ti ii line. A relative line strength measurement is made of the Ti ii H-band line of interest and a reference line with a previously reported absolute transition probability. This ratio is measured using multiple spectra of a high-current water-cooled HC lamp recorded with a calibrated FT-IR spectrometer.