Central Bureau for Astronomical Telegrams
IAUC 6595: 46P; GS 1843+00
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Circular No. 6595
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET 46P/WIRTANEN
T. Farnham and D. Schleicher, Lowell Observatory, report on
narrow-band photometry of comet 46P with the 0.79-m telescope on
Mar. 5.1 UT, at r = 1.07: "Mean Haser-model production rates were
log Q(OH) = 27.89, log Q(CN) = 25.43, and log Q(C2) = 25.42, and
the mean dust-production rate was log (Af rho) = 2.08; combining
these results with those previously obtained with the Hall 1.07-m
telescope on Feb. 12.1 and 15.1 (r = 1.14-1.12 AU) implies that the
water production is essentially unchanged over this three-week
interval, while the CN and C2 production have increased by 50-60
percent and dust production has increased by over a factor of 2.
Our measured OH production in mid-Feb. is in good agreement with
the water production estimated by Bertaux based on Lyman-alpha
emission (IAUC 6565)."
K. Jockers, Max Planck Institute for Aeronomy, Katlenburg-
Lindau, reports that an H2O+ tail was detected in comet 46P with
the 2-m telescope of the Center AMEI at Peak Terskol in the
Northern Caucasus on Mar. 11.
GS 1843+00
T. Takeshima, Goddard Space Flight Center and Universities
Space Research Association, reports: "The countrate history of the
transient x-ray binary pulsar GS 1843+009 obtained with ASM onboard
RXTE indicates that the source intensity rose between 1997 Jan. 26
and Feb. 1 to a flux level of 15 mCrab in the band 2-10 keV and
remained at 15-30 mCrab level since then. This is the first time
that the source has been seen in the x-ray band since the discovery
with Ginga in Apr. 1988 (IAUC 4583, 4587). An RXTE observation
with PCA and HEXTE was carried out on Mar. 5.0875-5.2549 UT. The
averaged source countrate in PCA (2-60 keV) was 806 counts/s,
corresponding to a flux level of 62 mCrab. The pulse period
(barycentric) was 29.565 +/- 0.002 s at the epoch of Mar. 5.1712,
which is consistent with the recent BATSE results (IAUC 6586). The
obtained pulse period is about 0.2 percent longer than that
reported from Ginga observations. The pulse fraction is 31 percent
(peak to bottom). The pulse profile is double-peaked, but the
secondary minimum is 2.6 percent above the average. The energy
spectrum (2-60 keV) is expressed as a sum of an exponential cut-off
power-law component [photon index -0.20 +/- 0.06, cut-off energy
13.0 +/- 0.4 keV, and 2-10-keV flux of (1.09 +/- 0.12) x 10E-6 erg
sE-1 cmE-2] and a blackbody component [kT = 1.16 +/- 0.07 keV and
2-10-keV flux (2.4 +/- 0.2) x 10E-6 erg sE-1 cmE-2] with
photoelectric absorption by cold matter of nH = (6.2 +/- 0.5) x
10E22 cmE-2."
(C) Copyright 1997 CBAT
1997 March 19 (6595) Daniel W. E. Green
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