Small apparent outburst of comet 115P/Maury
ATel #13836; Michael S. P. Kelley (U. Maryland), Quanzhi Ye (U. Maryland), Dennis Bodewits (Auburn U.) on behalf of the Zwicky Transient Facility Collaboration; Brian Skiff (Lowell Obs.)
on 26 Jun 2020; 20:24 UT
Distributed as an Instant Email Notice Comets
Credential Certification: Quanzhi Ye (qye@umd.edu)
We report the discovery of an apparent outburst of comet 115P/Maury with the Zwicky Transient Facility (ZTF; Bellm et al. 2019, PASP, 131, a8002). Based on automated processing of nightly ZTF data, a small outburst occurred between 2020 Jun 19.36 and 2020 Jun 23.34 UTC. The event is initially apparent in two exposures in both photometry and morphology as a compact source centered on the coma. We followed-up on the event with images from the Lowell Observatory 0.8-m telescope taken 2020 Jun 24.20 UTC through an R-band filter.
Photometry measured in a 5" radius aperture (4100–6500 km) is tabulated below, calibrated to the PS1 catalog (ZTF; Tonry et al. 2012, ApJ 750, 99), or ATLAS-RefCat2 (Lowell; Tonry et al. 2018, ApJ 867, 105). We estimate the g–r color to be 0.49±0.01 mag, and fit a model to the effective r-band lightcurve: m = 11.4 + 5 log10(Delta) + 14 log10(rh) + Phi(phase), where Phi is the Halley-Marcus phase function (Schleicher & Bair 2011, AJ 141, 177) expressed in magnitudes (RMS of 0.06 mag). Based on this fit, the outburst was at least –0.3 mag. No other events are apparent in our data.
The comet is at low Galactic latitudes, but the ZTF image differencing pipeline mitigates stellar contamination, and the photometric apertures on Jun 23–26 avoided any significant stars. Monitoring of the comet is encouraged in case this event is followed by a larger one in the near future.
Date rh Delta Phase F m unc r Resid
(UTC) (au) (au) (deg) (mag) (mag) (mag) (mag)
------------- ---- ----- ----- - ----- ----- ----- -----
2020-04-27.44 2.21 1.64 25.3 g 18.57 0.05 18.08 -0.02
2020-04-27.46 2.21 1.64 25.3 r 18.19 0.05 18.19 0.09
2020-04-30.44 2.20 1.60 25.1 g 18.47 0.05 17.98 -0.05
2020-05-03.44 2.19 1.57 24.8 r 17.99 0.04 17.99 0.05
2020-05-03.46 2.19 1.57 24.8 g 18.47 0.04 17.98 0.04
2020-05-05.43 2.18 1.54 24.6 i 17.52 0.06 17.76 -0.13
2020-05-05.48 2.18 1.54 24.6 g 18.42 0.07 17.93 0.04
2020-05-06.43 2.18 1.53 24.5 r 17.87 0.05 17.87 0.00
2020-05-06.46 2.18 1.53 24.5 g 18.22 0.09 17.73 -0.14
2020-05-08.49 2.17 1.51 24.2 r 17.75 0.07 17.75 -0.06
2020-05-23.46 2.14 1.35 21.8 g 17.94 0.03 17.45 0.04
2020-05-26.35 2.13 1.33 21.2 g 17.83 0.03 17.34 0.01
2020-05-26.46 2.13 1.33 21.2 r 17.34 0.02 17.34 0.01
2020-06-01.40 2.12 1.27 19.8 g 17.70 0.03 17.21 0.04
2020-06-01.46 2.12 1.27 19.8 r 17.18 0.02 17.18 0.01
2020-06-16.36 2.09 1.17 15.7 g 17.33 0.05 16.84 0.06
2020-06-19.27 2.09 1.15 14.9 g 17.21 0.02 16.72 0.01
2020-06-19.36 2.09 1.15 14.8 r 16.70 0.02 16.70 -0.01
2020-06-23.34 2.08 1.13 13.7 g 16.81 0.02 16.32 -0.30
2020-06-23.38 2.08 1.13 13.7 r 16.33 0.01 16.33 -0.29
2020-06-24.20 2.08 1.13 13.4 r 16.46 0.03 16.46 -0.14
2020-06-26.46 2.08 1.12 12.8 r 16.40 0.02 16.40 -0.15
Columns: rh, heliocentric distance; Delta, observer-comet distance; Phase, Sun-comet-observer angle; F, photometric bandpass; m, apparent magnitude; unc, uncertainty on m; r, effective r-band lightcurve; and Resid, the residuals from the fit.
This work makes use of observations obtained with the Samuel Oschin Telescope 48-inch at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW.
