Electronic Telegram No. 3522
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@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET P/2013 EW_90 (TENAGRA)
     An apparently asteroidal object that was discovered on CCD images taken
with a 0.41-m f/3.75 astrograph at the Tenagra Observatories near Nogales,
AZ, U.S.A. (observers M. Schwartz and P. R. Holvorcem; discovery observations
tabulated below), was designated 2013 EW_90 by the Minor Planet Center on MPS
460682 based on a linkage of the discovery observations with Catalina Sky
Survey astrometry from Mar. 14; prediscovery Spacewatch observations from
Feb. 16 were identified later (as were Spacewatch observations also from Mar.
3.21-3.24 UT).  Luca Buzzi, Varese, Italy, writes that Hidetaka Sato obtained
images of 2013 EW_90 remotely on Apr. 30.15 using an iTelescope 0.51-m f/4.5
reflector near Mayhill, NM, U.S.A., after noting the object's unusual orbit
(cf. MPEC 2013-H04), finding a softer aspect with respect to field stars
and a coma up to 18" wide in stacked images; a 12" coma was found by Sato
on May 2.17.  Buzzi then obtained six 180-s images on May 3.4 in good seeing
with the 2.0-m f/10 "Faulkes Telescope North" at Haleakala, with the stacked
images measured by himself and S. Foglia, finding a diffuse coma at least 5"
wide.  Buzzi then found round 11"-12" coma on stacked images taken with a
0.60-m f/4.6 reflector at Varese on May 4.9, and a 9" coma with no tail on
images taken on May 6.9.  Buzzi adds that T. Lister (Las Cumbres Observatory
Global Telescope Network) obtained nine 300-s images with the 1.0-m f/8
Ritchey-Chretien telescope at McDonald Observatory (with the stacked images
measured by Buzzi, Foglia, and Lister), finding a 5" coma.

     2013 UT             R.A. (2000) Decl.       Mag.   Observer
     Mar.  3.18634   11 48 25.01   +10 24 49.6   19.0   Schwartz
           3.20194   11 48 24.52   +10 25 01.0   19.0     "
           3.21578   11 48 24.07   +10 25 11.3   19.1     "

The available astrometry, the following orbital elements by G. V. Williams
(from astrometry spanning Feb. 16-May 7) and an ephemeris appear on MPEC
2013-J52.

                    Epoch = 2012 Sept.30.0 TT
     T = 2012 Oct. 11.84051 TT        Peri. = 346.03197
     e = 0.1960060                    Node  = 160.36159 2000.0
     q = 3.3003350 AU                 Incl. =  31.81056
       a =  4.1049246 AU   n = 0.11850763   P =   8.32 years


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 May 13                      (CBET 3522)              Daniel W. E. Green