Electronic Telegram No. 4274
Central Bureau for Astronomical Telegrams
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COMET 252P/LINEAR
     J.-Y. Li and N. H. Samarasinha, Planetary Science Institute; M. S. P.
Kelley, University of Maryland; D. Farnocchia, Jet Propulsion Laboratory,
California Institute of Technology; and M. Mutchler, Space Telescope Science
Institute, report on imaging of comet 252P obtained starting on Mar. 14.24
(44-min duration) and Apr. 4.67 UT (exposure duration about 9 hr) with the
Hubble Space Telescope (+ WFC3/UVIS).  A faint enhancement in the anti-
sunward direction is consistent with the tail.  The dust coma shows a strong
enhancement in the sunward direction within about 1".5 (about 100 km at the
comet) for both epochs.  The r'-band partial lightcurve measured in the Apr.
4 images in a 0".2-radius aperture shows variability of about 0.14 mag or
larger; this partial lightcurve is not consistent with the 7.35-hr period,
but is consistent with a periodicity of about 5.5 hr or its multiples.  The
r'-band mean value of Af(rho) is 13 cm for Mar. 14 and 46 cm for Apr. 4 in a
0".2-radius aperture, where A is the albedo of the grains, f is the filling
factor of the grains, and rho is the radius of the field-of-view; cf. A'Hearn
et al. 1984, A.J. 89, 579).  Image enhancement with 1/rho normalization shows
that the sunward feature moves about the nuclear condensation on Apr. 4
between p.a. about 50 and 110 deg, consistent with a 7.35-hr period (Knight
and Schleicher, CBET 4271).  Continued observations are encouraged in order
to determine the rotational state of 252P.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2016 CBAT
2016 April 24                    (CBET 4274)              Daniel W. E. Green