Central Bureau for Astronomical Telegrams
IAUC 3451: BLUE STAR IN SNR 1006; LINE EMISSION FROM THE CRAB; Occn OF AGK3 +001022 BY (3)
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Circular No. 3451
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
BLUE STAR IN SNR 1006
F. Schweizer, Cerro Tololo Interamerican Observatory, writes:
"A very blue star lies within the boundary of the remnant of the
supernova of 1006 at R.A. = 14h59m36s.78, Decl. = -41o47'31".7 (equinox
1950.0), 2'.8 south-southeast of the center given by van den Bergh
(1978, Ap. J. Suppl. 38, 119). Photoelectric measurements on 1979
Sept. 20 and 21 give = 16.74, U-B = -1.07, B-V = -0.14 and V-R =
-0.12. Spectra obtained with the 4-m telescope in 1979 Feb. and on
1980 Jan. 9 show Balmer absorption lines up to H-10, no measurable
Balmer jump, various He I lines, but no He II lines. H-gamma and H-delta are
~ 1.2 nm wide at 80 percent of continuum and have equivalent widths
of ~ 0.7 nm each. The heliocentric radial velocity is -13 +/- 30
km/s. A preliminary analysis of these data gives Teff = 38 500 +/-
4500K, log g = 6.7 +/- 0.6 and Mv = +6.2 +/- 1.8, which puts the star
in the transition region between late O or early B subdwarfs and
white dwarfs. With Av = 0.34 +/- 0.1, the distance is 1.1 kpc
(within a factor of two), in rough agreement with the probable supernova
distance of ~ 1.3 kpc. Therefore, it is a possibility that this
star is the remnant itself or is associated with it. During a 22-min
continuous observation with the 4-m telescope starting on 1979
Apr. 25d02h42m UT J. Middleditch, Lawrence Berkeley Laboratory,
found no periodic variation above a limit of 0.35 percent pulsed
fraction for frequencies between 0.002 and 50 Hz. Further
observations at all wavelengths are suggested."
LINE EMISSION FROM THE CRAB
P. Ubertini, A. Bazzano, C. D. La Padula and V. F. Polcaro,
Laboratono di Astrofisica Spaziale, Frascati; and R. K. Manchanda,
Tata Institute of Fundamental Research, Bombay, communicate: "We
report the discovery of a line feature between 64 and 76 keV in the
spectrum of the Crab. Observations in the hard x-ray range were
made with a high-pressure Xe-multiwire proportional counter during
a trans-Mediterranean balloon flight on 1979 Aug. 26. Results are
consistent with a line intensity of ~ 2 x 10**-3 ph cm**-2 s**-1 and a
line width of ~ 5 keV. The pulsed fraction of the source is ~ 20
percent of the total integrated emission in the range 20-130 keV."
OCCULTATION OF AGK3 +001022 BY (3) JUNO
Corrigendum. On IAUC 3444, lines 6-9 from foot, add the
University of Hawaii to the list of institutions involved.
1980 February 8 (3451) Brian G. Marsden
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