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



                                       Konkoly Observatory
                                       Budapest
                                       18 May 1963


                            3 C 273


     In No. 23 of these Bulletins the light variation of the radio
source 3 C 273 was announced by Dr. EFREMOV and Dr. SHAROV from
the Sternberg Astronomical Institute, Moscow. According to a letter
by Dr. Harlan J. SMITH from the Yale University Observatory (New
Haven Conn. U.S.A.), he and Miss Dorrit HOFFLEIT found - 
independently of the above named - in March the light of this object to be
variable. They estimated about 600 magnitudes of it on Harvard plates
and sent a summary of these observations to the British journal Nature
on 9 April. Dr. SMITH asks individuals having plates from which
magnitudes of 3 C 273 can be estimated to be so kind and to 
communicate the magnitudes to him (or the existence of the plates) for the
master light curve which he is assembling on IBM cards.

     So far he has about 1400 observations from Harvard plates but
in particular the years before 1920 and after 1952 are in desperate
need of more observations.

     As Dr. SMITH writes, he interprets the several modes of variations 
as indicating that the luminous source in 3 C 273 may in fact be a
hyper-star of around 10^6 and 10^7 solar masses, pulsating under
gravity. This interpretation is consistent with the photometric 
observations and furthermore relates to the recent remarks by HOYLE and
FOWLER to the effect that a class of hyper-stars in this mass range
may exist (MN 125 No.2; Nature, 9 February 1963).


                                        L. DETRE
                                         editor