Langland-Shula, Laura E.Vogt, Steven S.Charbonneau, DavidButler, PaulMarcy, Geoff2019-09-242009Langland-Shula, Laura E., Steven S. Vogt, David Charbonneau, Paul Butler, and Geoff Marcy. 2009. “A HIRES/KECK SPECTROSCOPIC INVESTIGATION OF THE MEASUREMENT OF SODIUM IN THE ATMOSPHERE OF HD 209458b.” The Astrophysical Journal 696 (2): 1355–66. https://doi.org/10.1088/0004-637x/696/2/1355.0004-637X1538-4357http://nrs.harvard.edu/urn-3:HUL.InstRepos:41397471We present high-resolution High Resolution Echelle Spectrometer (HIRES)/Keck spectra of HD 209458, and a Monte Carlo variation on the basic method used by other workers, to look for the excess in-transit absorption in the NaD doublet at 5893 angstrom due to the extrasolar planet. The HIRES data, binned by bandpass, allow a direct comparison with previous results. We find >3 sigma results in most test bandpasses around the NaD doublet, including relative absorption of (-108.8 +/- 25.7) x 10(-5) in the "narrow" bandpass used by other workers. This is approximate to 4.7 times larger than the "narrow" results reported by Charbonneau et al. for HD 209458b. However, >2 sigma absorption is detected in some weak Fe I and Ni I lines that were tested for comparison, raising concern about the uncertainties introduced by continuum-fitting and terrestrial atmosphere subtraction.en-USJournal Article2019-09-2410.1088/0004-637X/696/2/1355