Central Bureau for Astronomical Telegrams
IAUC 2837: A0620-00; N Cyg 1975; N Aql 1975; N Per 1974
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Read IAUC 2838
Circular No. 2837
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS
A0620-00
B. Peterson, Anglo-Australian Observatory; and D. Jauncey and
A. E. Wright, C.S.I.R.O. Radiophysics, report that two observations
of the Boley-Wolfson star identified with A0620-00 (IAUC 2819) made
with the image-tube dissector scanner on the 400-cm telescope show
the Na D line in absorption (interstellar?) and emission lines of
N III 4634-4640 A and He II 4686 A. The peak flux in the emission
lines was about 10 percent of the continuum flux. The continuum
flux had declined in the red by 0.5 magnitude at 6000 A and by 0.3
magnitude at 5000 A with respect to the flux from 3500 to 4000 A
between the observations on Sept. 8 and Sept. 10.
J. Bortle, Brooks Observatory, sends the following visual
magnitude estimates: Sept. 14.38 UT, 11.4; 15.38, 11.4.
NOVA CYGNI 1975
C. de Vegt, Hamburg Observatory, provides the following final
position (cf. IAUC 2826), derived from plates obtained with the 23-cm
astrograph by U. Gehlich: R.A. = 21h09m52s.827, Decl. = +47o56'41".25
(equinox 1950.0, epoch 1975.661); the position is in the FK4 system,
and the m.e. in each coordinate is +/- 0".05. Other accurate positions
that have been reported are as follows (end figures only):
52s.85, 41".4 (C. A. Murray, Royal Greenwich Observatory); 52s.88,
41".0 (R. S. Harrington, U.S. Naval Observatory); 52s.88, 40".2 (H.
Kosai, Tokyo Observatory); 52s.89, 41".5 (E. de Graeve, Vatican
Observatory); 52s.87, 41".1 (G. Martin, Leander McCormick Observatory).
R. H. Koch and C. W. Ambruster, Flower and Cook Observatory,
report that observations with a two-channel pulse counter in yellow
and blue gave light minima on Sept. 10.070 and 10.208 UT. These
were consistent with simultaneous single-channel, four-bandpass
observations by A. B. Hull. The period, if any, was not less than
0.275 day. Light maxima were observed on Sept. 10.128 and 10.268
UT. The amplitudes were 0.11 magnitude (approximately) in the
ultraviolet, 0.15 magnitude in blue, 0.12 magnitude in yellow and ~
0.06 magnitude in red. BD +48 3305 was seemingly a good comparison.
J. C. Kemp and R. J. Rudy, Department of Physics, University
of Oregon, write: "We monitored the linear polarization at 0.365,
0.45 and 0.70 um on nine nights from Aug. 30 to Sept. 11 UT at Mauna
Kea. The mean values (percent) were p = 1.22, 1.28 and 1.20, respectively,
all at angles close to theta = 47o.7. No changes Delta-p greater
than 0.15 were seen, but possible changes Delta-theta of up to 2o were noted
on two or three occasions, suggesting only very small intrinsic
effects. Narrow-band polarimetry over the entire range 0.35-1.6 um
on Sept. 3.5 and 5.5 showed a normal interstellar-like curve with p(1.55
um) = 0.49 and p(1.1 um) = 0.60. No feature of amplitude greater than
Delta-p = 0.2 and Delta-theta = 3o was seen in H-alpha, using 15-A filters.
The circular polarization was measured with high accuracy on the
nights of Aug. 31 and Sept. 2 and 5. The mean q values in nine
filter bands 0.35-1.5 um showed (in units of 10**-4 or 0.01 percent)
an underlying interstellar-type curve with maxima q = +1.0 at 0.75 um
and q = -1.0 at 0.365 um; the apparent zero crossing agrees with the
linear-polarization maximum at 0.52 um. There is also a large feature
in q(x) around H-alpha. The feature appears S-shaped with peak-to-peak
Delta-q about 2.0. The longward peak is negative and just cancels
the interstellar-like component at about 0.7 um, but augments it to
about +2.0 at 0.64 um. A lesser structure seems present around H-beta.
While suggesting Zeeman splitting, this effect would require fields
in the kilogauss range. This seems impossible if the outgoing
shell has reached a radius of 10**8 km, unless the shell is concentrated
in lobes. If a magnetic field is carried out with the outburst,
it will no doubt disperse with time. Our simultaneous spectrophotometric
observations showed that the broad H-alpha emission was
of magnitude about zero (in a 15-A filter) on Aug. 31 and decayed
only to magnitude 1.0 on Sept. 5.5. Magnitudes at 1.6 um were 2.1
and 2.7 on Sept. 3.5 and 5.5, respectively. Apart from the Balmer
emissions and the ultraviolet excess, the energy curve on those
dates somewhat resembled a Planck curve with T = 4900o."
The following recent visual magnitude estimates have been
reported: Sept. 11.02 UT, 5.9 (K. Simmons, Jacksonville, Florida);
11.04, 6.6 (J. Bortle, Brooks Observatory); 11.12, 6.4 (P. Maley,
Houston, Texas); 12.12, 6.4 (Maley); 13.12, 6.5 (Maley); 14.02, 6.8
(L. Jacchia, Cambridge, Massachusetts); 14.06, 6.7 (Bortle); 14.1,
7.6 (R. Lukas, Wilhelm Foerster Observatory); 15.02, 6.9 (Jacchia);
15.05, 6.7 (Bortle); 15.13, 6.8 (D. Wallentine, Albuquerque, New
Mexico); 15.15, 6.5 (Maley); 16.20, 6.8 (Maley).
Corrigendum. IAUC 2829, line 31: for Sept. 1.13 and 1.40 read
Aug. 31.13 and 31.40.
NOVA AQUILAE 1975
The following visual magnitude estimates have been made by J.
Bortle, Brooks Observatory: Sept. 3.06 UT, 14.5; 6.03, 14.7.
NOVA PERSEI 1974
Recent magnitude estimates by U. Hopp and U. Surawski, Wilhelm
Foerster Observatory: Sept. 8.09 UT, 13.0; 9.02, 13.1.
1975 September 18 (2837) Brian G. Marsden
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