Central Bureau for Astronomical Telegrams
IAUC 5038: 1990h; V725 Tau
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Read IAUC 5039
Circular No. 5038
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
PERIODIC COMET JOHNSON (1990h)
J. Gibson, OAO Corporation and Jet Propulsion Laboratory,
reports his recovery of this comet with the Palomar 1.5-m reflector
(+ CCD + Gunn r filter). The comet's image is stellar within the
limits of seeing, and the following positions are in agreement
with the orbital elements on MPC 12123 (ephemeris on MPC 15732):
1990 UT R.A. (1950) Decl. m2
June 17.37291 19 06 08.34 -15 15 42.3 18
17.38258 19 06 08.01 -15 15 45.8
18.34399 19 05 36.27 -15 20 58.5
18.35634 19 05 35.81 -15 21 02.9
18.37122 19 05 35.29 -15 21 07.9
V725 TAURI
C. Blanco, Astronomy Institute, Catania University; A. Mammano,
Department of Mathematics, Messina University; and R. Margoni,
Asiago and Ekar Observatories, communicate: "Seven hundred UBVRIJ
photoelectric magnitudes (already published or new) of V725 Tau =
HDE 245770 = A0535+26 appear modulated by three long periods, P
(probably in the ratios 4:2:1), with phases of minima reckoned from
JD 2443204 (1977 Mar. 1.5 UT). We give here, at 99.5-percent
confidence level, the B and V amplitudes (A) and phases (phi), using
different periodgrams: P = 988 +/- 14 days, A(B) = 0.06 +/- 0.01,
phi(B) = 0.70 +/- 0.07, A(V) = 0.08 +/- 0.1, phi(V) = 0.70 +/- 0.11;
P = 496 +/- 9 days, A(B) = 0.03 +/- 0.01, phi(B) = 0.1:, A(V) = 0.06
+/- 0.01, phi(V) = 0.1:; P = 249 +/- 4 days, A(B) = 0.03 +/- 0.01,
phi(B) = 0.2:, A(V) = 0.04 +/- 0.01, phi(V) = 0.2:. No modulations
were found in the H and K infrared bands. The two giant x-ray
outbursts at JD 2442534 (1975 May 1) and 2444520 (1980 Oct. 7),
uncorrelated with periastron passage (Margoni et al. 1988, A.Ap. 195,
148), occurred about two 988-day periods after (phase 0.1 past
maximum). A dozen flashes that are comparable to the largest amplitude
of the lightcurve (or greater by up to 2-3 mag) have been recorded,
the two greatest lasting 0.2-0.3 s (Urasin et al. 1986, Astron. Zirk.
No. 1492). We are searching for a couple of periods that are much
shorter, which could in turn give origin to the longer ones."
1990 June 26 (5038) Daniel W. E. Green
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