IAU Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 3241: 1978 P 1; 1978 (532) 1; 1977n

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).


Read IAUC 3240  SEARCH Read IAUC 3242
IAUC number


                                                  Circular No. 3241
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


1978 P 1
     Capt. J. C. Smith, U.S. Navy, reports: "Elongation of the
photographic image of Pluto has been detected by J. W. Christy on
plates taken with the U.S. Naval Observatory's 155-cm astrometric
reflector on 1978 Apr. 13, 20 and May 12; 1970 June 13, 15, 16, 17
and 19; and 1965 Apr. 29 and May 1.  The maximum elongation is
~0"9 in p.a. 170o-350o.  Observed position angles are consistent
with a uniform revolution/rotation period equal to the lightcurve
period of 6.3867 days.  The data suggest that there is a satellite,
2-3 magntiudes fainter than Pluto, revolving around Pluto in this
period at a mean distance of ~20 000km; the implied sun-Pluto
mass ratio is 140 000 000:1.  The other orbital elements are: e ~ 0,
Node = 350o, Incl = 105o (with respect to the plane of the sky),
T(Node) = 1978 May 12.2 UT.  The probable satellite was confirmed on
exposures with the 155-cm reflector on 1978 July 2 and 5 and by J. A.
Graham with the 400-cm reflector at Cerro Tololo Interamerican Observatory
on July 6.  Further observations are very desirable; a brief ephemeris
follows."

  1978 UT    p.a.   Sep.        1978 UT    p.a.   Sep.
  July  8.2  357o   0"8         July 12.2  165o   0"9
        9.2  342    0.8              13.2  129    0.3
       10.2  277    0.2              14.2    5    0.6
       11.2  181    0.7              15.2  384    0.9

     The designation 1978 P 1 conforms with the temporary
nomenclature system for announcing discoveries of new satellites.
This system was approved at the meeting in June of the IAU Working
Group for Planetary System Nomenclature and has been submitted for
endorsement at the forthcoming meeting of the IAU Executive
Committee.


1978 (532) 1
     As a result of predictions by G. E. Taylor and D. W. Dunham,
three successful observations were made of the occultation of SAO
120774 by (532) Herculina on June 7.  These have led to an accurate
determination of 217 +/- 3 km for the diameter of this minor planet,
assumed to have circular cross-section.  The observers were E.
Bowell and M. A'Hearn at the Lowell Observatory; J. McMahon near
Boron, California; and K. Horne near Rosamond, California.  A
second stellar extinction, seen from Lowell and Boron, is interpreted
as due to a 50-km-diameter companion to Herculina at an angular
separation of 0"863 +/- 0"001 (corresponding to a projected distance
of 975 +/- 1 km).  Assuming that Herculina and its satellite
have a similar albedo, the satellite should be about 3 magnitudes
fainter than Herculina and should thus currently have V ~ 13.  The
satellite might therefore be directly detectable either visually or
photographically.  Dr. Bowell wishes to be informed of positive of
negative attempts to confirm the satellite; his address is: Lowell
Observatory, P.O. Box 1269, Flagstaff, AZ 86002, U.S.A.
     The designation 1978 (532) 1 is used as a logical extension of
the temporary nomenclature system noted above.


PERIODIC COMET COMAS SOLA (1977n)
     Continuation to the ephemeris on IAUC 3079:

1978/79 ET   R.A. (1950) Decl.  Delta    R    For dT = +1d   m2
                                               dRA  dDecl
July 31      6h22m27 +26o00'1   2.724  1.941  -1m40 - 3'4   17.6
Aug. 10      6 50.00 +26 21.0                 -1.46 - 2.4
     20      7 18.03 +26 25.6   2.576  1.899  -1.51 - 1.3   17.3
     30      7 46.14 +26 14.0                 -1.55 - 0.1
Sept. 9      8 14.08 +25 47.1   2.432  1.875  -1.57 + 1.1   17.2
     19      8 41.61 +25 06.3                 -1.57 + 2.3
     29      9 08.53 +24 13.8   2.292  1.870  -1.56 + 3.5   17.0
Oct.  9      9 34.63 +23 12.2                 -1.55 + 4.7
     19      9 59.73 +22 04.4   2.155  1.884  -1.52 + 5.8   16.9
     29     10 23.68 +20 53.9                 -1.48 + 6.9
Nov.  8     10 46.32 +19 43.9   2.019  1.917  -1.45 + 7.9   16.9
     18     11 07.50 +18 38.1                 -1.41 + 8.9
     28     11 27.05 +17 39.5   1.883  1.966  -1.38 + 9.8   16.8
Dec.  8     11 44.77 +16 51.6                 -1.36 +10.7
     18     12 00.43 +16 16.9   1.746  2.030  -1.35 +11.7   16.8
     28     12 13.78 +15 57.9                 -1.35 +12.7
Jan.  7     12 24.48 +15 56.1   1.615  2.107  -1.38 +13.8   16.8
     17     12 32.23 +16 12.0                 -1.42 +14.8
     27     12 36.75 +16 44.4   1.504  2.195  -1.48 +15.8   16.8
Feb.  6     12 37.81 +17 30.1                 -1.55 +16.6
     16     12 35.46 +18 23.0   1.438  2.290  -1.64 +17.1   16.9
     26     12 30.06 +19 15.1                 -1.71 +17.1
Mar.  8     12 22.36 +19 57.2   1.447  2.392  -1.76 +16.6   17.1
     18     12 13.49 +20 21.2                 -1.76 +15.7
     28     12 04.68 +20 22.2   1.551  2.499  -1.72 +14.5   17.4
Apr.  7     11 57.04 +19 59.1                 -1.64 +13.1
     17     11 51.37 +19 14.4   1.752  2.609  -1.53 +11.9   17.9
     27     11 48.01 +18 12.0                 -1.40 +10.7
May   7     11 47.04 +16 56.4   2.030  2.721  -1.28 + 9.7   18.4
     17     11 48.28 +15 31.4                 -1.16 + 8.8
     27     11 51.47 +13 59.9   2.363  2.834  -1.05 + 8.1   18.9
June  6     11 56.33 +12 24.3                 -0.95 + 7.5
     16     12 02.58 +10 46.2   2.726  2.948  -0.86 + 6.9   19.4


1978 July 7                    (3241)              Brian G. Marsden

Read IAUC 3240  SEARCH Read IAUC 3242


Our Web policy. Index to the CBAT/MPC/ICQ pages.


Valid HTML 4.01!