COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                       Number 3149



                                     Konkoly Observatory
                                     Budapest
                                     19 February 1988

                                     HU ISSN 0374-0676


                 A NEW EPHEMERIS FOR RW ARIETIS

  The main purpose of this note is to establish new light elements for the
variable star RW Arietis and put in agreement the photoelectric observations
performed by Bookmyer et al. (1977) and Penston (1972). Such a problem is 
accessible if we do not take into consideration the photoelectric observations
from JD 2439384, 2439505, 2439507, 2440335 and 2440337. These last observations
could be influenced by an unknown cause.
   Figure 1 shows the common light curve of RW Arietis plotted with the newly
derived ephemeris

           JDmax  = 2439475.6618 + 0.3543145d E.
            
Here dots and open circles represent Bookmyer's et al. (1977) and Penston's
(1972) observations, respectively.
   The ephemeris determined above agrees with Detre's (1937) observations, as we
can see in the following table.


Max. hel.      E            O-C
2428000+
074.550     -32178        +0d020
154.273     -31953        + .022
181.203     -31877        + .025
183.299     -31871        - .005
407.603     -31238        + .018
408.622     -31235        - .026
431.649     -31170        - .030
455.419     -31103        +0.001


  The available observational data taken here into consideration seem to agree
with the old proposal that RW Arietis is an RR Lyrae variable of type c in
Bailey's classification.


                                [FIGURE 1]




  I. TODORAN

Centre for Astronomy and Space Sciences
  Astronomical Observatory
  Cluj-Napoca, Romania



References

Bookmyer, B.B., Fitch, W.S., Lee, T.A., Wisniewski, W.Z., Johnson, H.L., 1977,
      Rev. Mexicana Astron. Astrofisica 2, 235. [BIBCODE 1977RMxAA...2..235B ]
Detre, L., 1937, Astron. Nachr. 262, 81. [BIBCODE 1937AN....262...81D ]
Penston, M.J., 1972, Mon. Not. Roy. Astron. Soc. 156, 103. [BIBCODE 1972MNRAS.156..103P ]