Circular No. 9215
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A. 
CBATIAU@EPS.HARVARD.EDU           ISSN 0081-0304
URL http://www.cbat.eps.harvard.edu/index.html  
Prepared using the Tamkin Foundation Computer Network


COMET C/2011 L4 (PANSTARRS)
     Richard Wainscoat, Institute for Astronomy, University of 
Hawaii, reports that an object discovered on four CCD images taken 
with the 1.8-m "Pan-STARRS 1" telescope at Haleakala (discovery 
observation tabulated below) appeared to show slight non-stellar 
appearance; three follow-up 30-s r-band exposures were then 
acquired by M. Micheli and Wainscoat with the Canada-France-Hawaii 
Telescope on Mauna Kea (queue observer Lisa Wells) on June 7.44 UT, 
showing that a coma is definitely visible with a subtle hint of a 
faint tail towards p.a. 60 deg.  After posting on the Minor Planet 
Center's 'NEOCP' webpage, other CCD astrometrists have commented on 
the object's cometary appearance.  Images taken by R. Holmes 
(Ashmore, IL, USA, 0.61-m astrograph; June 7.25-7.26), and measured 
by S. Foglia and T. Vorobjov, show the object's profile to be 30 
percent larger than those of nearby stars.  G. Sostero and E. Guido 
write that fourteen stacked unfiltered 180-s images taken remotely 
on June 7.4 with a 0.35-m reflector at the Tzec Maun Observatory 
near Mayhill show the object to be slightly diffuse with a hint of 
elongation toward the northeast.  H. Sato (Tokyo, Japan; remotely 
using a 0.50-m reflector at the RAS Observatory near Mayhill, NM, 
U.S.A.; June 8.3) finds a 6" coma of total red mag 18.5.

     2011 UT             R.A. (2000) Decl.       Mag.              
     June  6.38910   16 10 41.08   -16 38 39.8   19.4

The available astrometry (including May 24 prediscovery observations 
from Mt. Lemmon), the following preliminary parabolic orbital 
elements by G. V. Williams, and an ephemeris appear on MPEC 2011-L33.

     T = 2013 Apr. 17.1236 TT         Peri. = 331.6636
                                      Node  =  64.2255  2000.0
     q = 0.364374 AU                  Incl. = 104.7422


COMETS C/2009 Y16 AND C/2009 Y17 (STEREO)
     Further to IAUC 9200, additional slightly diffuse Kreutz 
sungrazers have been found on STEREO HI-1 website images.  Peak 
approximate magnitudes:  C/2009 Y16, 10-11; C/2009 Y17, 10.

 Comet        2009 UT       R.A.(2000)Decl.   Inst.  F    MPEC
 C/2009 Y16   Dec. 30.183   23 19.8  - 8 23   HI-1   AW   2010-O31 
 C/2009 Y17        30.711   23 22.2  - 7 50   HI-1   AW   2010-O31 

                      (C) Copyright 2011 CBAT
2011 June 8                    (9215)            Daniel W. E. Green