COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 832

	                                Konkoly Observatory
        	                        Budapest
                	                1973 October 14

         BRIGHTENING OF HERBIG-HARO OBJECT NO. 1


Slow time variations have been observed or suspected in the structure
of several Herbig-Haro Objects for which long series of direct photographs
of uniform quality and adequate scale are available. The best-documented
case is HH 2 = Haro 12_a (Herbig, Non-Periodic Phenomena in variable Stars,
p.75,1968).
I wish here to call attention to a new example: the brightening of one portion 
of the brightest known Object, HH 1 = Haro 11_a, also near NGC 1999.
This Object has the form of a 4" x 8" ellipse, elongated in about p.a.130d.
The best 120-inch direct plates show that there are 3 or 4 very sharp nuclei
within this small area, together with considerable nebulous structure.  In
1959-60, when the first 120-inch plates were obtained, the two star-like
nuclei at the northwest end of this Object were very faint. They must also
have been very faint (although unresolved) on 36-inch (Crossley) reflector
plates extending back to 1946 because in those years HH 1 always appeared as
a slightly diffuse star with only a very short, curved nebulous tail extending
for 5" toward the northwest (Herbig, Ap.J.113,697,1951).  At some time
between 1962 and 1968, during the only large gap in the Lick plate series,
one or both of the close pair of faint nuclei (separation 1") at the northwest
end of this Object underwent a large increase in brightness.  A very slight
further rise may have taken place between 1968 and 1973.  As a consequence,
the northwest end of HH 1 - formerly the faint end - now dominates the
structure, and appears at Crossley scale (39"/mm) like a star of m_pg  ~ 16.0
with a nebulous appendage to the southeast, in the opposite sense as before.
Possibly this brightening is related to the changes in the integrated spectrum
of HH 1 that were noted by Bohm, Perry, and Schwartz (Ap.J. 179, 149, 1973)
between 1955 and 1969.
The gradual changes in the structure of the nearby Object HH 2 (described
in 1968) continue. Nucleus H is now the brightest point in HH 2 at about
m_pg = 16.2. This came about as the result of a slow, steady increase since
its initial rise from invisibility prior to 1953. Nucleus A itself has
disappeared except for an appendage, or possibly another nucleus, slightly
north of the original position of A; this feature is now about mag. 18.0.
There have been only small changes in the other nuclei of HH 2 since 1968.


   I am very indebted to Mr. E. A. Harlan, who has obtained all of the
Crossley plates in this series since 1968.



                     G. H. Herbig

                     Lick Observatory
                     University of California
                     Santa Cruz, California    95064
                     U.S.A.

                     1973 October 2