[IAUC] CBET 2823: 20110923 : 2011 CR42

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2823
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


2011 CR42
     A. Waszczak, California Institute of Technology; and E. O. Ofek and D.
Polishook, Weizmann Institute of Science, report that CCD images (1".01/pixel)
of 2011 CR42, taken by the "Palomar Transient Factory" (PTF; cf. Law et al.
2009, PASP 121, 1395; Rau et al. 2009, PASP 121, 1334) on Mar. 5 and 6 with
the 1.2-m f/2.44 Oschin Schmidt telescope, suggest that this minor-planet-
designated object may have episodic cometary activity.  The object
consistently had a FWHM nearly twice that of all similar-magnitude SDSS-
referenced stars (York et al. 2000, A.J. 120, 1579), thus suggestive of a
cometary coma.  This could not be caused by trailing, as the object's motion
was < 1"/min.  No sign of a cometary tail was visible before or after stacking
the images.  Six g-band 60-s astrometric observations are tabulated below in
MPC format.

     K11C42R  C2011 03  5.47755 11 25 21.43 +17 05 13.2          17.8 g      I41
     K11C42R  C2011 03  6.14243 11 24 51.10 +17 08 12.8          17.9 g      I41
     K11C42R  C2011 03  6.19523 11 24 48.60 +17 08 27.1          17.8 g      I41
     K11C42R  C2011 03  6.23933 11 24 46.50 +17 08 39.1          18.0 g      I41
     K11C42R  C2011 03  6.43924 11 24 36.90 +17 09 32.7          17.6 g      I41
     K11C42R  C2011 03  6.48991 11 24 34.48 +17 09 46.0          17.7 g      I41

The object was 2.92 AU from the sun and approaching perihelion (q = 2.53 AU on
2011 Nov. 30.0 TT).  The object is currently on the earth's day side and will
not be observable until after perihelion.  Based on its current 86-day orbital
solution (MPO 198577) and photometric parameters (H = 13.0, G = 0.15), the PTF
survey should have acquired pre-discovery observations of 2011 CR42 in 2010
Feb. and Dec., at predicted magnitudes 19.2 and 18.8, when the object was at
3.8 and 3.1 AU from the sun, respectively.  Upon inspection of these earlier
images, no source was found within 200" of the predicted position brighter
than mag 20.5.  These null detections may be indicative of recent and
relatively abrupt cometary activity.


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                         (C) Copyright 2011 CBAT
2011 September 23                (CBET 2823)              Daniel W. E. Green