COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2701

                                  Konkoly Observatory
                                  Budapest
                                  1 April 1985

                                  HU ISSN 0374 - 0676



      Ca II H AND K LINE VARIABILITY IN THE Ap STAR HD 43819


    HD 43819 (HR 2258), which was classified as a B9IIIp Si,(Cr)
star (Cowley 1972), is a single wave photometric variable with a
period of 1.0785 days (Winzer 1974). I obtained several 4.3 A/mm
IIaO spectrograms with the 2.5-m telescope at Mt. Wilson
Observatory and several 8.9 A/mm IIaO spectrograms with the coude
feed telescope at Kitt Peak National Observatory and borrowed
additional spectrograms from the Mt. Wilson Observatory plate
file and staff. While studying the intensity vs. wavelength
tracings of these plates, I noticed that the Ca II H and K line
profiles contained a second component on several spectrograms, my
Mt. Wilson Observatory spectrograms Ce21999 and Ce22006 as well
as the 4.5 A/mm Palomar Observatory spectrogram Pb11415. But
these lines are definitely single on my Mt. Wilson Observatory
spectrogram Ce22576 as well as on two 9 A/mm Palomar Observatory
spectrograms (Pc8488 and Pc9981), a 10.4 A/mm Mt. Wilson
Observatory spectrogram (Ce15086), and three of my Kitt Peak
Observatory spectrograms (D3899c, D6018, D6031). My Kitt Peak
Observatory spectrogram D4410a suggests that the K line is single
while the H line may contain a second component. The difference
in midexposure times between Ce21999 and Ce22006 is 24 hours and
23 minutes which is consistent with Winzer's period. However,
the uncertainty in the period does not permit the use of the
midexposure times of the other spectrograms which show H and K
lines with secondary minima to improve the period of variability



   A careful examination of the 4.3 and 4.5 d/mm spectrograms
did not reveal any evidence for second components in   lines
other than the H and K lines. The apparent rotation velocity is
14 km/s (Wolff and Preston 1978). But the maximum separation
of the two components of the H and K lines is observed to be 19
km/s, which may well be a lower limit. If HD 43819 has a
companion which produces the sharp-lined secondary mimima in the
H and K lines, it must be rather weak-lined or of somewhat later
spectral type and less luminous. On the other hand, if the
profile variations are due to spectrum variability as seen in
many other Ap stars, then the metal lines may be formed over only
part of the visible hemisphere. This would reduce the observed
line width and permit a reconciliation of the observed maximum
separation of the H and K line components and the observed value
of v sin i.




   This research was supported in part by a NRC-NASA Research
Associateship. The plate material was obtained while the author
was a Guest Investigator at the Hale Observatories and a Visiting
Astronomer at Kitt Peak National Observatory.




                  SAUL J. ADELMAN
                  Code 681
                  Laboratory for Astronomy and Solar Physics
                  NASA Goddard Space Flight Center
                  Greenbelt, MD 20771 USA



References:
Cowley, A., 1972, Astron. J., 77, 750. [BIBCODE 1972AJ.....77..750C ]
Winzer, J.E., 1974, Ph.D. Thesis, University of Toronto [BIBCODE 1974PhDT........61W ]
Wolff, S.C., and Preston, G.W., 1978, Astrophys. J. Suppl., 37, 371. [BIBCODE 1978ApJS...37..371W ]