COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 579

                                 Konkoly Observatory
                                 Budapest
                                 1971 September 9


       ORION FLARE STARS IN FEBRUARY 1971

      According to schedule (1) during the Orion region
X-ray monitoring the region has been observed photographically. 
Observations have been carried out at the 40 cm
astrograph of the Sternberg Institute South Station; ZU-2
plates have been used. Multiple exposure method has been
used to search for flares of stars. Data of observations
fulfilled are gathered in Table I. Total monitoring time
is about 10h.

                    Table I
-----------------------------------------------
Date   Time of    Exposure   Duration
1971 observation  numbers   of exposures
Febr.   (UT)
-----------------------------------------------
18   16h45m-18h16m  7         12m
     18 28 -19 11   7         5m
19   17 46 -19 01   6         12m
     19 39 -20 44   5         12m
20   18 09 -19 19   7         9m
22   17 19 -18 23   5         12m
23   17 00 -18 15   6         12m
     18 20 -18 37   2         12m, 5m
     20 00 -20 38   4         6m, 6m, 12m, 12m
----------------------------------------------


     The plates obtained have been measured at the iris
photometer using Andrews' standards (2) for calibration
curves. The known flare stars listed in (3,4) have been 
measured. Data for two flares found are given in Table II.

                     Table II
---------------------------------------------------
Number    Date of     R.A.     D.      m_B Deltam_B
of star                  1900.0
in (3,4)  observ.
---------------------------------------------------
206        18        5h29.1m -5d41'   15.5m  >1m
231        23        5h31.3m -5d16'   16.2m   0.8m
---------------------------------------------------

---------------------------------------------------
Number   Time of flare maxima  Duration
of star            (UT)        of flares
in (3,4) 
---------------------------------------------------
206      17h51m  -18h03m         >40m
231      17h37.5m-17h49.5m       > 1h
---------------------------------------------------


       In both cases the following stellar images - the
 exposure 18h04m-18h16m for star N 206 and the exposure
 17h50m-18h02m for star N 231 - are overlapped by neighbour
 stars and therefore they cannot be measured.


1. IBVS, 1971, N. 516.
2. Andrews A. D., 1970, Bol.Obs.Tonantzintla y Tacubaya, 34,
   195, [BIBCODE 1970BOTT....5..195A ]
3. Haro G., 1968, Stars and Stellar Systems, Vol. VII,
   "Nebulae and Interstellar Matter", eds. Middlehurst,
   B.M., and Aller, L.H., (Univ.Chicago Press) p. 141. [BIBCODE 1968nim..book..141H ]
4. Haro G., 1969, Bol.Obs.Tonantzintla y Tacubaya, 32, 79. [BIBCODE 1969BOTT....5...79H ]


 Crimean Astrophysical Observatory,
 Sternberg Institute South Station



                            A.N. KULAPOVA