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IAUC 7048: XTE J0111.2-7317; C/1998 U5

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                                                 Circular No. 7048
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Phone 617-495-7244/7440/7444 (for emergency use only)


XTE J0111.2-7317
     D. Chakrabarty, A. M. Levine, and G. W. Clark, Massachusetts
Institute of Technology; and T. Takeshima, Goddard Space Flight
Center, NASA, and Universities Space Research Association, write:
"Multiple observations of the SMC X-1 field with the Proportional
Counter Array (PCA) on the Rossi X-ray Timing Explorer between Oct.
29 and Nov. 7 have revealed a previously unknown 31-s x-ray pulsar,
designated XTE J0111.2-7317, about 30' from SMC X-1.  Raster scans
of the region on Nov. 6 and 7 have yielded the following position
for the new pulsar:  R.A. = 1h11m.2, Decl. = -73o17'.4 (equinox
2000.0), with an error radius of 1'.5 (90-percent confidence).  The
2-10-keV x-ray intensities of XTE J0111.2-7317 and SMC X-1 on Nov.
6.6 UT were 36(7) and 51(4) mCrab, respectively, and the pulsed
fraction of XTE J0111.2-7317 was roughly 45 percent.  If XTE
J0111.2-7317 is located in the SMC, its x-ray intensity implies a
luminosity of order 10E38 erg/s.  The source was not detected
during a series of six PCA observations of the field between Oct.
16 and 27.  Observations at other wavelengths are encouraged in
order to identify the binary companion."
     C. A. Wilson and M. H. Finger, Marshall Space Flight Center,
NASA, report:  "Hard-x-ray observations with the BATSE all-sky
monitor on the Compton Gamma Ray Observatory first detected XTE
J0111.2-7317 on Oct. 30, with a barycentric pulse frequency of
0.0322275(8) Hz on Oct. 30.5 UT.  The 20-50-keV pulsed intensity
increased from 18(3) mCrab on Oct. 30 to 37(3) mCrab on Nov. 5 and
remained steady through Nov. 9.  The pulse profile in the band
20-50 keV consists of a single asymmetric peak.  BATSE pulse-phase
measurements during Nov. 2-8 are consistent with a barycentric
pulse frequency of 0.03225181(3) Hz on Nov. 5.0 and a constant
pulse frequency derivative of 5.58(4) x 10E-11 Hz/s.  If this rate
is primarily due to the accretion torque on the pulsar, it implies
a luminosity of at least 10E38 erg/s, consistent with the distance
to the SMC."


COMET C/1998 U5 (LINEAR)
     Total visual magnitude and coma-diameter estimates: Nov. 7.76
UT, 10.0, 2'.8 (K. Hornoch, Lelekovice, Czech Republic, 0.35-m
reflector); 8.72, 10.2, 1'.0 (T. Karhula, Virsbo, Sweden, 0.20-m
reflector); 9.87, 10.2, 2'.5 (R. J. Bouma, Groningen, The
Netherlands, 0.25-m reflector); 10.89, 9.9, 3'.0 (Bouma).

                      (C) Copyright 1998 CBAT
1998 November 11               (7048)            Daniel W. E. Green

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