Apparent Outburst of Comet 97P/Metcalf-Brewington
ATel #15016; Michael S. P. Kelley (Univ. of Maryland), Tim Lister (Las Cumbres Observatory), Kritti Sharma (IITB), Vishwajeet Swain (IITB), Harsh Kumar (IITB), Varun Bhalerao (IITB), G. C. Anupama (IIA), Sudhanshu Barway (IIA), on behalf of the Zwicky Transient Facility Collaboration, the LCO Outbursting Objects Key Project, and the GROWTH India Collaboration
on 5 Nov 2021; 20:55 UT
Credential Certification: Tim Lister (tlister@lco.global)
We report an apparent outburst of comet 97P/Metcalf-Brewington discovered with the Zwicky Transient Facility (ZTF; Bellm et al. 2019, PASP, 131, a8002) and confirmed in GROWTH-India Telescope and Las Cumbres Observatory data. ZTF observed comet 97P between 2021 Oct 22 and 2021 Nov 02 UTC. Within a 5" radius aperture, the comet initially had a near constant apparent brightness, with i=18.23+/-0.09, and 18.17+/-0.07 mag, on 2021 Oct 22 at 07:22 and Oct 25 at 07:26 UTC, respectively (PS1 photometric system). By the next observational epoch, the comet had brightened to r=17.16+/-0.03 and i=16.95+/-0.03 mag on Nov 02 at 06:27 and 07:36, respectively. At this time, the outburst ejecta was already extended out to a radius of 15.2" (19,400 km). This morphology suggests the outburst may have already been a few days old at the time of discovery. Within 15.2" radius apertures, the total post-outburst brightness was r=16.22+/-0.03 mag, with a total outburst strength of -1.5+/-0.1 mag. Follow-up observations with the GROWTH-India Telescope at the Indian Astronomical Observatory and a Las Cumbres Observatory 1-m telescope at the South African Astronomical Observatory confirm the brightening, with r=17.34+/-0.08 and 17.35+/-0.01 mag on 2021 Nov 02 at 15:36 UTC and 2021 Nov 3 at 21:53 UTC, respectively (5" radius apertures). On Nov 2, the comet was at a heliocentric distance of 2.68 au and a geocentric distance of 1.76 au.
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, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the 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.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/
