J/MNRAS/521/1518 Comet 162P/Siding Spring photometry (Donaldson+, 2023)
Characterizing the nucleus of comet 162P/Siding Spring using ground-based
photometry.
Donaldson A., Kokotanekova R., Rozek A., Snodgrass C., Gardener D.,
Green S.F., Masoumzadeh N., Robinson J.
<Mon. Not. R. Astron. Soc. 521, 1518 (2023)>
=2023MNRAS.521.1518D 2023MNRAS.521.1518D (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Comets ; Photometry ; Optical
Keywords: comets: general - comets: individual: 162P/Siding Spring
Abstract:
Comet 162P/Siding Spring is a large Jupiter-family comet with
extensive archival lightcurve data. We report new r-band nucleus
lightcurves for this comet, acquired in 2018, 2021 and 2022. With the
addition of these lightcurves, the phase angles at which the nucleus
has been observed range from 0.39° to 16.33°. We
absolutely-calibrate the comet lightcurves to r-band Pan-STARRS 1
magnitudes, and use these lightcurves 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±0.001h, and a rotation pole oriented towards eclipitic
longitude λE=118°±26° and latitude
βE=-50°±21°. Using the shape model to correct the
lightcurves for rotational effects, we derive a linear phase function
with slope β=0.051±0.002mag/deg 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°. 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.
The challenges associated with modelling the shapes of comet nuclei
from lightcurves are highlighted, and we comment on the extent to
which we anticipate that LSST will alleviate these challenges in the
coming.
Description:
We have combined all published optical light curves of the nucleus of
162P/Siding Spring collected between 2007 and 2017 with new light
curves obtained in 2018, 2021, and 2022.
The new light curves were obtained in 2018 April (ID 13-15), 2018
July (ID 16-18), 2021 December (19-21), 2022 January (ID 22-28),
and 2022 March (ID 29-33)
Orbital Elements:
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Code Name Elem q e i H1
d AU deg mag
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162P P/Siding Spring 2457214.5 1.2373502 0.5951367 27.786352 13.10
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 34 911 162P photometry
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d JD Julian Date (no light time correction)
16- 21 F6.3 mag rmag Apparent PS1 magnitude
23- 28 F6.3 mag H0 Absolute magnitude (beta = 0.051 mag/deg)
30- 34 F5.3 mag unc Photometric calibration uncertainty
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Acknowledgements:
Abbie Donaldson, donaldso(at)roe.ac.uk
(End) Patricia Vannier [CDS] 23-Feb-2023