Central Bureau for Astronomical Telegrams
IAUC 4648: 1988l; G 24-9
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Circular No. 4648
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 617-495-7244/7440/7444
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
COMET 1988l (SMM 3)
O. C. St. Cyr, Solar Maximum Mission, NASA Goddard Space Flight
Center, reports his discovery of another probable sungrazing comet
with the SMM coronagraph (cf. IAUC 4621). Measurements by S. A. Beck,
High Altitude Observatory, have been reduced by the SMM Flight
Dynamics Facility:
1988 UT R.A. (1950) Decl.
June 27.63958 6 19 48 +22 46.2
27.65069 6 19 58 +22 49.8
27.66250 6 20 02 +22 52.8
27.69306 6 20 48 +23 02.4
27.70486 6 21 00 +23 06.6
27.71667 6 21 22 +23 09.0
27.72222 6 21 34 +23 13.2
As before, the measurements are estimated as good to +/- 0.1 solar
radius and +/- 0.1-deg position angle, and SMM 3 was not detected as
it receded from the sun. The estimated magnitude was very roughly -1.
B. G. Marsden, Center for Astrophysics, suggests that the comet is a
member of the Kreutz group and provides the orbital elements T = 1988
June 27.78 UT, Peri. = 84.5, Node = 5.5, Incl. = 144.5 (equinox
1950.0), q = 0.0053 AU.
G 24-9
C. Carilli and S. Conner, Massachusetts Institute of Technology,
write: "Observations made at the McGraw-Hill Observatory on July
15.3 UT show that G 24-9, a DQ7 white dwarf (proposed as a
spectrophotometric standard by Filippenko and Greenstein 1984, P.A.S.P.
96, 530), was fainter than R = 19, compared to its normal brightness of
R = 15.6. Proper motion was properly accounted for. The parallax of
0".0398 +/- 0".0050 was measured by Harrington and Dahn (1980, A.J. 85,
454). A similar variation was reported by Landolt (IAUC 4125)
when the star dropped from its normal V = 15.76 to V = 18.3 on 1985 Oct.
7.11; he suggested that it was probably an eclipsing system, and our new
observation implies that if the diminution were caused by the same
object, which would have to be a planet or other dark object larger than
the earth, the period would be 1013 days or an integer fraction thereof.
Multiple occulting objects, however, cannot be excluded."
1988 August 30 (4648) Daniel W. E. Green
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