TY - JOUR
T1 - Characterizing the nucleus of comet 162P/Siding Spring using ground-based photometry
AU - Donaldson, A.
AU - Kokotanekova, R.
AU - Rozek, A.
AU - Snodgrass, C.
AU - Gardener, D.
AU - Green, S. F.
AU - Masoumzadeh, N.
AU - Robinson, J.
N1 - Funding Information:
The authors would like to thank the referee, David Schleicher, for insightful and helpful comments on this manuscript. We also thank Samuel Jackson for the useful discussions. This work was supported by the UK Science and Technology Facilities Council. This work was also facilitated by support from the International Space Science Institute in the framework of International Team 504 ‘The Life Cycle of Comets’. RK acknowledges support by ESO through the ESO Fellowship. This work was supported in part by the ESO SSDF 21/22 (Student) Garching funding program. The new light curves presented were based on observations made with the Isaac Newton Telescope (UK PATT programmes I/2018A/07 and I/2022A/07), the Liverpool Telescope (programme XPL21B13), and the ESO New Technology Telescope [programme 0101.C-0709(A)]. Previously reported light curves were based on observations at the European Southern Observatory under ESO programmes 089.C-0372(A) and 089.C-0372(B), the WHT and INT under UK PATT programmes W/2007A/20 and I/2017A/05, and the 2-m telescope at Rozhen Observatory, Bulgaria. The Pan-STARRS 1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation.
Funding Information:
The Pan-STARRS 1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation.
Funding Information:
This work was supported by the UK Science and Technology Facilities Council. This work was also facilitated by support from the International Space Science Institute in the framework of International Team 504 ‘The Life Cycle of Comets’. RK acknowledges support by ESO through the ESO Fellowship. This work was supported in part by the ESO SSDF 21/22 (Student) Garching funding program.
Publisher Copyright:
© The Author(s) 2023. Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2023/5/1
Y1 - 2023/5/1
N2 - Comet 162P/Siding Spring is a large Jupiter-family comet with extensive archival lightcurve data. We report new r-band nucleus light curves for this comet, acquired in 2018, 2021, and 2022. With the addition of these light curves, the phase angles, at which the nucleus has been observed, range from 0.39◦ to 16.33◦. We absolutely calibrate the comet light curves to r-band Pan-STARRS 1 magnitudes, and use these light curves to create a convex shape model of the nucleus by convex lightcurve inversion. The best-fitting shape model for 162P has axis ratios a/b = 1.56 and b/c = 2.33, sidereal period P = 32.864 ± 0.001 h, and a rotation pole oriented towards ecliptic longitude λE = 118◦ ± 26◦ and latitude βE = −50◦ ± 21◦. We constrain the possible nucleus elongation to lie within 1.4 < a/b < 2.0 and discuss tentative evidence that 162P may have a bilobed structure. Using the shape model to correct the light curves for rotational effects, we derive a linear phase function with slope β = 0.051 ± 0.002 mag deg−1 and intercept Hr(1, 1, 0) = 13.86 ± 0.02 for 162P. We find no evidence that the nucleus exhibited an opposition surge at phase angles down to 0.39◦. The challenges associated with modelling the shapes of comet nuclei from light curves are highlighted, and we comment on the extent to which we anticipate that Legacy Survey of Space and Time will alleviate these challenges in the coming decade.
AB - Comet 162P/Siding Spring is a large Jupiter-family comet with extensive archival lightcurve data. We report new r-band nucleus light curves for this comet, acquired in 2018, 2021, and 2022. With the addition of these light curves, the phase angles, at which the nucleus has been observed, range from 0.39◦ to 16.33◦. We absolutely calibrate the comet light curves to r-band Pan-STARRS 1 magnitudes, and use these light curves to create a convex shape model of the nucleus by convex lightcurve inversion. The best-fitting shape model for 162P has axis ratios a/b = 1.56 and b/c = 2.33, sidereal period P = 32.864 ± 0.001 h, and a rotation pole oriented towards ecliptic longitude λE = 118◦ ± 26◦ and latitude βE = −50◦ ± 21◦. We constrain the possible nucleus elongation to lie within 1.4 < a/b < 2.0 and discuss tentative evidence that 162P may have a bilobed structure. Using the shape model to correct the light curves for rotational effects, we derive a linear phase function with slope β = 0.051 ± 0.002 mag deg−1 and intercept Hr(1, 1, 0) = 13.86 ± 0.02 for 162P. We find no evidence that the nucleus exhibited an opposition surge at phase angles down to 0.39◦. The challenges associated with modelling the shapes of comet nuclei from light curves are highlighted, and we comment on the extent to which we anticipate that Legacy Survey of Space and Time will alleviate these challenges in the coming decade.
KW - comets: general
KW - comets: individual: 162P/Siding Spring
UR - http://www.scopus.com/inward/record.url?scp=85161220701&partnerID=8YFLogxK
U2 - 10.1093/mnras/stad616
DO - 10.1093/mnras/stad616
M3 - Article
AN - SCOPUS:85161220701
SN - 0035-8711
VL - 521
SP - 1518
EP - 1531
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -