COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2069

                                 Konkoly Observatory
                                 Budapest
                                 1982 January 11

                                 HU ISSN 0374-0676

            PERIODIC ERUPTIONS IN T CrB?


The recurrent nova T Coronae Borealis has been observed to erupt
four times, to our knowledge, with novae or flarelike events with
peak amplitude of one magnitude or greater. These eruptions are
summarized in the table below. We have calculated the orbital
phase of each event based on a period of 227.6 days measured for
the system by spectroscopic methods (Kraft 1958).

     Event                  Epoch(JD)  Orbital Phase(cycles)
------------------------------------------------------------
Nova T CrB 1866              2402734        (0.00)
Nova T CrB 1946              2431861       127.97
Flarelike event 1963(Ianna   2438030       155.08
1964)
Event of 1975(Radick 1981)   2442543       174.91
------------------------------------------------------------

The relative phases of all three events subsequent to Nova T CrB
1866 are within 0.10 cycle of phase 0.00. The probability of
such a coincidence being fortuitous is less than one per cent.
T CrB does exhibit smaller outbursts throughout its orbit, but
we consider only those of large amplitude here. Both the 1963
and 1975 events were observed in the ultraviolet.

Because of the suggested periodicity in these data, we recommend
that T CrB be monitored in the ultraviolet by photometrists for
three weeks either side of orbital phase zero. This will next
occur about April 7, 1982.


                      LEIGH HUNT PALMER
                      Simon Fraser University
                      Burnaby, British Columbia
                      Canada


                      JOHN L. AFRICANO
                      Kitt Peak National Observatory
                      Tucson, Arizona
                      U.S.A.


References:
Kraft, Robert P., 1958, Astrophys. J. 127, 625 [BIBCODE 1958ApJ...127..625K ]
Ianna, Phillip A., 1964, Astrophys. J. 159, 780 [BIBCODE 1964ApJ...139..780I ]
Radick, Richard R., 1981, Private Communication