Central Bureau for Astronomical Telegrams
IAUC 3088: 3U 1626-67; MXB1637-53; 3U 1908+00; VV Pup; HM Sge; HD 165590
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Read IAUC 3089
Circular No. 3088
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 Telex: 921428
Telephone: (617) 864-5758
3U 1626-67
H. Bradt, K. Apparao, R. Doxsey and J. G. Jernigan, Massachusetts
Institute of Technology, report the x-ray position, obtained
with the SAS-3 Observatory, of the 7s.68 x-ray pulsar 3U 1626-67
(IAUC 3054; Rappaport et al. preprint) to be R.A. = 16h27m13s.6, Decl. =
-67o21'23" (equinox 1950.0). Since the uncertainty (90-percent-confidence)
is only 25", the optical counterpart suggested by van
Paradijs et al., 2'.6 west of this position (IAUC 3084), can clearly
be excluded.
J. E. McClintock, Massachusetts Institute of Technology, suggests
for the optical counterpart a star that lies 8" from the new
x-ray position. It has a large ultraviolet excess and is located
(with an uncertainty of +/- 3") at R.A. = 16h27m14s.2, Decl. = -67o21'16"
(equinox 1950.0); it is situated 25" south and 4" west of a V =
14.9 star, 33" north and 8" east of a V = 15.5 star. The new
candidate's photometric parameters, measured at Cerro Tololo, are (+/-
0.15 magnitude) V = 18.5, U-B = -1.2, B-V = +0.2.
MXB1637-53
McClintock also reports that he has discovered at Cerro Tololo
a possible optical counterpart of 2S 1636-536 = 3U 1636-53, which
has been identified as an x-ray burst source (IAUC 3025) and is
currently under scrutiny during the worldwide watch of these objects
(IAUC 3078). The optical candidate, located (with an uncertainty
of +/- 3") at R.A. = 16h36m56s.2, Decl. = -53o39'15" (equinox 1950.0),
is 15" from the centroid of the x-ray position given by Jernigan et
al. (to be submitted to Nature); it is designated as star No. 3 in
their finding chart of the region. The object has a large ultraviolet
excess, its photometric parameters (+/- 0.10 magnitude) being
V = 17.55, U-B = -0.65, B-V = +0.65.
3U 1908+00
J. R. Thorstensen, P. A. Charles and S. Bowyer, Department of
Astronomy and Space Sciences Laboratory, University of California
at Berkeley, report the discovery of a faint star, normally of
magnitude ~ 20, that exhibits flaring intervals during which it
reaches magnitude 17 or brighter. The star, located (with an uncertainty
of +/- 2") at R.A. = 19h08m42s.9, Decl. = +0o30'05" (equinox
1950.0), is about 10" from the center of the 20"-radius error
circle given for 3U 1908+00 = Aql X-l by SAS 3 and is referred to as
star No. 5 by Doxsey et al. (to be submitted to Nature). The
optical flares coincide with the intense x-ray activity of Aql X-1 in
June 1975 and June 1976 (IAUC 2788, 2965; Buff et al. 1977, Astrophys.
J. 212, 768), thereby establishing the identification.
VV PUPPIS
H. E. Bond, Louisiana State University, reports that observations
with the 400-cm telescope and integrating television system
at Cerro Tololo show that VV Pup has resumed its normal photometric
activity that had ceased in April (cf. IAUC 3065). Very active
flickering, with rapid rises up to about magnitude 14, were observed
during a 40-min interval beginning about June 20d23h20m UT,
after which the star eclipsed and dropped to about magnitude 17.
HM SAGITTAE
B. W. Bopp, University of Toledo, writes: "Spectrograms of HM
Sge (IAUC 3081, 3083) covering the wavelength region 5800-7500 A
with a dispersion of 40 A/mm were obtained at Ritter Observatory on
June 22.3 UT. The spectrum appears essentially the same as that
observed by Stover and Sivertsen (1977, Astrophys. J. 214, L33) in
Dec. 1976. In addition to very strong H-alpha emission, the following
emission lines were observed: 5876, 6678, 7065, 7281 A He I; 6300 A
[O I]; 6310 A [S III]; 6548, 6584 A [N II]; 7136 A [A III]; 7319,
7330 A [O II].
K. M. Merrill, University of Minnesota, reports the following
infrared magnitudes, obtained at Mount Lemmon on June 9.4 UT: 2.3 um,
4.1; 3.5 um, 1.9; 4.9 um, 1.0; 8.4 um, 0.6; 11.2 um, -1.6; 12.5 um, -1.4.
Limited higher-resolution l0-um data confirm moderate silicate
emission superimposed on a continuum of color temperature 950 K.
HD 165590
C. L. Morbey and J. M. Fletcher, Dominion Astrophysical Observatory,
report that HD 165590 (R.A. = 18h03m.7, Decl. = +21o26', equinox
1950.0) = ADS 11060 AB (V = 7.2, 8.5), a visual binary with P = 20
years and e = 0.97 (Van Biesbroeck 1954, Publ. Yerkes Obs. 8, 317)
has recently been shown by Morbey et al. (to be published) to be a
spectroscopic-visual triple system. Recent observations (dispersion
6 A/mm) with the 122-cm telescope at Victoria indicate that
periastron is approaching rapidly. Spectroscopic observations made
over the next year or so will be extremely valuable for the determination
of the relat1ve radial velocities of the center of mass of
the spectroscopic pair and the other component of the visual pair.
1977 July 11 (3088) Brian G. Marsden
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