Apparent Outburst of Comet 7P/Pons-Winnecke
ATel #15772; Michael S. P. Kelley (Univ. Maryland), Quanzhi Ye (Univ. Maryland), Abbie Donaldson (Univ. Edinburgh), Brian Murphy (Univ. Edinburgh), Colin Snodgrass (Univ. Edinburgh), Cyrielle Opitom (Univ. Edinburgh) on behalf of the Zwicky Transient Facility Collaboration, and the LCO Outbursting Objects Key Project
on 22 Nov 2022; 16:19 UT
Credential Certification: Colin Snodgrass (csn@roe.ac.uk)
We report an apparent outburst of comet 7P/Pons-Winnecke, first identified in Zwicky Transient Facility (ZTF; Bellm et al. 2019, PASP 131, a8002) images. The comet was not detected in two images taken on 2022 Nov 20 with the following 3-sigma upper-limit brightnesses: g>20.8 mag at 06:07 UTC and r>20.6 mag at 07:48 UTC. Photometry was measured in 5-arcsec radius apertures and reported in the PS1 photometric system. On Nov 21, two successive g-band images with a mid-time of 07:19 UTC, show a compact source (2.5-arcsec seeing) at the ephemeris position of the comet, measuring g=19.60 (0.09) mag in a 5-arcsec radius aperture. At the time of the apparent outburst, the comet was at 4.42 au from the Sun, 3.47 au from the Earth, and a Sun-comet-Earth angle of 4.0 deg.
The outburst is confirmed with data taken at the 2.5-m Isaac Newton Telescope. Pre-outburst observations taken on 2022 Nov 19 at 00:23 UTC had an apparent r-band brightness of 21.58 (0.07) mag, while images taken on Nov 21 at 22:27 UTC have r = 19.69 (0.07) mag. Photometry was measured in 1.0-arcsecond radius apertures (pixel scale 0.33â/pix) and calibrated to the PS1 photometric system. Together the data indicate a relative outburst strength of -1.89 (0.10) mag for the given aperture size and bandpass.
Additional confirmation is obtained from observations of comet 7P with a Las Cumbres Observatory 1-m telescope at Cerro Tololo Interamerican Observatory. Photometry from images taken at 2022 Nov 22 07:13 UTC within a 5-arcsec radius aperture yield an r-band magnitude of 19.20 (0.02) mag (PS1 system).
Based on observations obtained with the Samuel Oschin Telescope 48-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-2034437 and a collaboration including Caltech, IPAC, Weizmann Institute for Science, Oskar Klein Center at Stockholm University, University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, TANGO Consortium of Taiwan, University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, and IN2P3, France. Operations are conducted by COO, IPAC, and UW.
This work makes use of observations from the Las Cumbres Observatory global telescope network.
