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Berkeley Astronomical Department,
UNIVERSITY OF CALIFORNIA PUBLICATIONS
LICK OBSERVATORY BULLETIN
SIX STARS WHOSE RADIAL VELOCITIES VARY
Following is a list of six stars which were found to have variable velocities, from observations secured by the D. 0. Mills Expedition to the Southern Hemisphere, prior to August 1, 1913. Their announcement has been held awaiting the confirmation of further observations. Except where otherwise noted the plates were secured with a spectrograph of two-prism dispersion. The last column gives the number of stellar lines measured, or when this number is followed by the letter "s" the number of sections measured with the Hartmann spectro-comparator.
Epuppis (a = 7l1 8T9; 8 = —40° 19'; Mag. 5.4; Class A5)
17 s. stronger!
14 s, stronger?
On the spectrograms of January 21 and February 8,1913, the lines are double. The two spectra are of
The spectrum consists of fairly broad lines of hydrogen, helium, carbon and magnesium. The appearance of the lines on the spectrogram of February 17, 1913, seems to be different from that of the lines on the other three plates obtained with the two-prism spectrograph. Some of this may arise from differences of exposure, but part of it appears to be a real change in the character of the lines. A comparison of the two-prism spectrograms on the Hartmann spectrocomparator verifies the variation in velocity indicated above.
Of the stars whose radial velocities are being determined by the D. O. Mills Expedition to the Southern Hemisphere a number observed during the past year give indications of having variable velocities. For several of these the observed variations are such as to make a confirmation by further observations desirable. The range observed for four stars is sufficient, however, to remove all doubt as to the reality of this variation, and for these the necessary data are given below. Except where noted the spectrograms were obtained with a one-prism spectrograph. The number of lines from which the radial velocity was determined follows the measurer's name.