Circular No. 5298 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Telephone 617-495-7244/7440/7444 (for emergency use only) TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505 MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN SUPERNOVA 1991ai IN IC 4434 C. Pollas, Observatoire de la Cote d'Azur, reports his discovery on OCA Schmidt tech pan films of an apparent supernova in IC 4434 (R.A. = 14h25m32s.62, Decl. = +16 25'49".1, equinox 1950.0). The supernova, of mag 18.5 on July 2.93 and 3.93 UT, is located at R.A. = 14h25m33s.09, Decl. = +16 25'43".9. Nothing is visible to mag 21 on a plate taken Apr. 20.0, nor is anything present on POSS prints at the position of SN 1991ai. There is a star of mag about 15 located at R.A. = 14h25m33s.50, Decl. = +16 27'46".9. SVS 13 J. Eisloffel, E. Gunther, F. V. Hessman, R. Mundt, and R. Poetzel, Max-Planck-Institut fur Astronomie, Heidelberg; S. Beckwith, Cornell University; J. Carr, University of Hawaii; and T. Ray, Dublin Institute for Advanced Studies, communicate: "We confirm the optical outburst of SVS 13, the exciting source of Herbig-Haro objects 7-11 (cf. IAUC 5261; R.A. = 3h25m58s.15, Decl. = +31 05'45".2, equinox 1950.0). According to our CCD archives and recently obtained CCD images from the Calar Alto 3.5-m telescope, the outburst of about 3 mag occurred between 1988 Dec. and 1990 Sept. Our CCD frames taken through a narrowband red filter (central wavelength 674 nm) show that the source was still rising by about 0.06 mag/month between 1990 Sept. and 1991 Feb. 9 (our last measurement). A similar outburst amplitude is observed at V, R, and I. On 1991 Jan. 17, we measured B = 22.8, V = 20.2, R = 18.1, and I = 16.0 at the ESO/ MPI 2.2-m telescope. Infrared photometry carried out in early 1991 Jan. at the Palomar 5-m telescope provided the following magnitudes: J = 11.84, H = 9.92, K = 8.05, L' = 5.66, M = 4.28, and N = 1.5. Compared to the measurements of Cohen and Schwartz from 1981 Dec. (Ap.J. 265, 877), the outburst amplitude is 1.8 mag in H, 1.2 mag in K, and 0.35 mag in N. An optical spectrum in the red of SVS 13 obtained on 1990 Nov. 19 at the Calar Alto 3.5-m telescope shows emission lines (H-alpha, Fe II 651.6-nm) typical of a T Tau star or Herbig-Ae star. An infrared spectrum around 2.3 microns obtained on 1990 Dec. 17 at the University of Hawaii 2.2-m telescope shows no change (compared to 1986 Oct.) in the equivalent widths of the CO emission band heads (nu = 2-0 and 3-1). Follow-up observations at optical, infrared, and radio wavelengths are urgently required to monitor the unique outburst of this famous young outflow source." 1991 July 5 (5298) Daniel W. E. Green
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