Are the Spectral Lines Truly Varying?
Dr. Gray’s paper claims that the asymmetry in the spectral lines of 51 Peg vary with an amplitude of 45 m/s. However his errors are probably ~20 m/s. One cannot determine these errors, as Nature publishes papers without mention of uncertainties or error bars. The supposed extent of variations in the line-profiles is only twice the errors we estimate. Thus, Gray’s effect must be confirmed. Further, in the persuasive “binned” plot, Gray and Nature binned the data points together according to “natural groupings of the points”. The data points are thus grouped together by eye, rather than in equal intervals. Another paper accepted for publication in the Astrophysical Journal by Hatzes, Cochran, and Johns-Krull states: “We find no evidence for variability in the velocity span of the spectral line bisectors greater than the error of the measurements (sigma = 20 m/s).” These spectral line shapes were obtained using 50% higher spectral resolution, and they include analysis of eight spectra
