Central Bureau for Astronomical Telegrams
IAUC 5815: CH Cyg; V1974 Cyg
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Circular No. 5815
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
CH CYGNI
A. Skopal and M. F. Bode, Liverpool John Moores University; A.
Evans, University of Keele; and Z. Urban, D. Chochol, and L. Hric,
Astronomical Institute, Skalnate Pleso Observatory, communicate:
"There has been an increase in the activity of the symbiotic binary
CH Cyg (cf. IAUC 5504). Low-dispersion SWP and LWP, and high-
dispersion LWP, spectra were obtained with the International Ultraviolet
Explorer from the VILSPA station of the European Space Agency
on 1992 Nov. 24 and 1993 May 28. The level of the continuum
increased approximately by a factor of two, from 1.2 to 2.5 x 10E-12
erg cmE-2 sE-1 AE-1 around 150 nm (and at the limit of the spectrum
at 330 nm), and from 0.4 to 0.9 x 10E-12 erg cmE-2 sE-1 AE-1 at
around 240 nm, before any reddening correction was applied. The
line spectrum was characterized by absorption features, which were
strong on the later SWP spectrum, and emissions of Lyman-alpha, O
IV] + Si IV (140 nm), C IV (155 nm), O III] (166 nm), Si III] (189
nm), C III] (191 nm), C II] (233 nm), and [O II] (247 nm). The
high-resolution spectra exhibited numerous Fe II lines in absorption.
The Mg II 279.6- and 280.3-nm doublet emission lines are
each cut by two strong absorption components. Photoelectric
photometry carried out at Skalnate Pleso confirmed the recent increase
in activity, particularly in the U band: 1992 Nov. 18.96 UT, U =
9.496, B = 9.638, V = 8.242; Dec. 23.75, 8.184, 8.944, 8.014; 1993
Apr. 17.99, 7.55, 8.49, 7.82; June 1.90, 7.57, 8.39, 7.69."
V1974 CYGNI
G. S. Rossano, R. J. Rudy, R. C. Puetter, and D. K. Lynch,
Space and Environment Technology Center, The Aerospace Corporation,
write: "We have observed this object on June 3.5 UT with the Lick
Observatory 3-m Shane telescope and the Aerospace cooled scanning
germanium spectrometer. A spectrogram (range 750-1350 nm,
resolution 300-550) shows strong He I (1083.0 nm), weak Paschen-beta
through Paschen-epsilon, and weak lines of He II, [O II] (733.1 nm),
and [N I] (1040.0 nm). Also seen are the coronal lines [Fe XI] at
789.2 nm, [S VIII] at 991.1 nm, and [S IX] at 1252.0 nm. [S IX] is
now stronger than Paschen-beta. [Fe XIII] at 1074.7 and 1079.8 nm
appear blended with the He I 1083.0-nm feature. Unidentified
features at 1110, 1190, and 1200 nm observed in 1992 August and October
are still present. A monochromatic continuum magnitude of 12.8
at 1250 nm was observed."
1993 June 15 (5815) Daniel W. E. Green
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