J/MNRAS/462/S138 Robotic view of 67P perihelion (Snodgrass+, 2016)
The perihelion activity of comet 67P/Churyumov-Gerasimenko as seen by robotic
telescopes.
Snodgrass C., Opitom C., de Val-Borro M., Jehin E., Manfroid J., Lister T.,
Marchant J., Jones G.H., Fitzsimmons A., Steele I.A., Smith R.J.,
Jermak H., Granzer T., Meech K.J., Rousselot P., Levasseur-Regourd A.-C.
<Mon. Not. R. Astron. Soc. 462, S138 (2016)>
=2016MNRAS.462S.138S 2016MNRAS.462S.138S (SIMBAD/NED BibCode)
ADC_Keywords: Comets ; Photometry
Keywords: comets: individual: 67P/Churyumov-Gerasimenko
Abstract:
Around the time of its perihelion passage, the observability of
67P/Churyumov-Gerasimenko from Earth was limited to very short
windows each morning from any given site, due to the low solar
elongation of the comet. The peak in the comet's activity was
therefore difficult to observe with conventionally scheduled
telescopes, but was possible where service/queue-scheduled mode was
possible, and with robotic telescopes. We describe the robotic
observations that allowed us to measure the total activity of the
comet around perihelion, via photometry (dust) and spectroscopy (gas),
and compare these results with the measurements at this time by
Rosetta's instruments. The peak of activity occurred approximately two
weeks after perihelion. The total brightness (dust) largely followed
the predictions from Snodgrass et al., with no significant change in
total activity levels from previous apparitions. The CN gas production
rate matched previous orbits near perihelion, but appeared to be
relatively low later in the year.
Description:
Tables listing the observations of comet 67P taken around its 2015
perihelion, using various robotic telescopes, and the resulting R-band
photometry from these observations. Telescopes used are the 2m
Liverpool Telescope, La Palma, the 1.2m STELLA telescope, Tenerife,
the 0.6m TRAPPIST telescope, La Silla, and the network of 1m and 2m
telescopes operated by Las Cumbres Global Telescope network (LCOGT) at
the CTIO, Sutherland, McDonald and Siding Spring observatories.
Photometry is measured in an aperture with radius equal to 10000km
at the distance of the comet.
object.dat :
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Code Name Elem q e i H1
d AU deg mag
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67P P/Churyumov-Gerasimenko 2454890.5 1.2465141 0.6401757 7.040861 11.63
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 54 196 Log of observations described in this paper
tablea1.dat 55 593 R-band photometry
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See also:
J/A+A/520/A92 : Comet 67P global plasma parameter simulation (Gortsas+, 2011)
J/A+A/527/A113 : 67P/Churyumov-Gerasimenko R-band light curve (Tubiana+, 2011)
J/A+A/548/A12 : 67P/Churyumov-Gerasimenko R-band light curve (Lowry+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 "date" Obs.date Observation date
(2015-MM-DD.dd, UT time as fraction of day)
15- 22 A8 --- Tel Telescope/Instrument (1)
24- 25 I2 --- Nexp Number of exposures
27- 29 I3 s Texp Exposure time
31- 37 A7 --- Filter Filter(s) used (2)
39- 43 F5.3 AU r Heliocentric distance
45- 49 F5.3 AU Delta Geocentric distance
51- 54 F4.1 deg alpha Phase angle
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Note (1): Telescope/Instrument code as follows:
LT/IO:O = Liverpool Telescope, 2m, IO:O camera
LT/LOTUS = Liverpool Telescope, 2m, LOTUS spectrograph
STELLA = Tenerife Teide observatory, pair of 1.2-m telescopes
TRAPPIST = La Silla observatory, 60-cm robotic telescope
ogg-2m = LCOGT telescope, Haleakala, 2m
elp-1m = LCOGT telescope, McDonald, 1m
lsc-1m = LCOGT telescope, Cerro Tololo, 1m
coj-1m = LCOGT telescope, Siding Spring, 1m
Note (2): Filters use lowercase (g,r,i,z) for SDSS-type filters,
Rc for Cousins-R, and 'spec' to indicate spectroscopy (with the LOTUS
instrument on the LT, range 320-630nm).
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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- 13 A13 "date" Obs.date Observation date
(2015-MM-DD.dd, UT time as fraction of day)
15- 18 F4.2 au r Heliocentric distance
20- 26 F7.2 d DeltaT Time from perihelion
28- 33 F6.3 mag Rmag Apparent R-band magnitude
35- 40 F6.3 mag R(r.1.0) Reduced R-band magnitude, R(r,1,0) (1)
42- 46 F5.1 cm Afrho Afrho activity measure (no phase correction)
48- 55 A8 --- Tel Telescope/Instrument
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Note (1): Reduced magnitude is corrected for geocentric distance (Delta) and
phase angle (alpha) using:
R(r,1,0) = mag - 5*log10(Delta) - beta*alpha,
with phase function coefficient beta=0.02mag/°.
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Acknowledgements:
Colin Snodgrass, colin.snodgrass(at)open.ac.uk
(End) Colin Snodgrass [The Open University], Patricia Vannier [CDS] 13-Sep-2016