[Iaude] CBET 4502: 20180329 : (3552) DON QUIXOTE

quai at eps.harvard.edu quai at eps.harvard.edu
Thu Mar 29 11:40:08 EDT 2018

                                                  Electronic Telegram No. 4502
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

     M. Mommert, Lowell Observatory, writes that imaging observations
obtained by Mommert, D. Polishook (Weizmann Institute, Israel), and N.
Moskovitz (Lowell Observatory) using the 4.1-m Southern Astrophysical Research
Telescope (+ Goodman Spectrograph) at Cerro Pachon, Chile, on Mar. 26.40-26.41
UT show faint, extended emission around the Amor-type minor planet (3552) when
it was at r = 1.354 AU and Delta = 1.626 AU (T = 2018 May 7.6 TT at q = 1.24
AU).  The extended emission is concentrated in an aperture with a radius of
about 10"; the average surface brightness within an annulus with radii 3" and
6" is about 21 mag per square arcsec, and this was estimated from twenty-two
stacked 10-s exposures taken with a custom "VR" filter and calibrated using
solar-like stars from the SkyMapper catalogue.  The average seeing at the time
of the observations was 1".8 (FWHM).  Long exposures tracking on the target
show a faint tail about 30" long pointing in the anti-sunward direction
toward p.a. 230 degrees.  This is the first time that cometary activity has
been observed around (3552) at visible wavelengths.
     Activity was first discovered using 3.6- and 4.5-micron Spitzer Space
Telescope observations in 2009 (Mommert et al. 2014, Ap.J. 781, 25) and was
attributed to the sublimation of CO or CO_2 when r = 1.23 AU and Delta =
0.55 AU; then, there was extended emission found at 4.5 microns, but nothing
at 3.6 microns.  The extended emission was detectable within a radius of 1'
around the nuclear condensation; there was also a faint tail about 2' long
pointing away from the sun.  That activity was interpreted as molecular-band
emission from either CO or CO_2 (both of which have emission bands in the
Spitzer 4.5-micron passband, but not in the 3.6-micron passband).  The lack
of emission at 3.6 microns led the authors to believe that there was very
little dust production.

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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2018 CBAT
2018 March 29                    (CBET 4502)              Daniel W. E. Green

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