J/ApJ/776/L20 C/2012 S1 (comet ISON) R photometry (Meech+, 2013)
Outgassing behavior of C/2012 S1 (ISON) from 2011 September to 2013 June.
Meech K.J., Yang B., Kleyna J., Ansdell M., Chiang H.-F., Hainaut O.,
Vincent J.-B., Boehnhardt H., Fitzsimmons A., Rector T., Riesen T.,
Keane J.V., Reipurth B., Hsieh H.H., Michaud P., Milani G., Bryssinck E.,
Ligustri R., Trabatti R., Tozzi G.-P., Mottola S., Kuehrt E., Bhatt B.,
Sahu D., Lisse C., Denneau L., Jedicke R., Magnier E., Wainscoat R.
<Astrophys. J., 776, L20 (2013)>
=2013ApJ...776L..20M 2013ApJ...776L..20M
ADC_Keywords: Comets ; Photometry, RI
Keywords: comets: general; comets: individual: ISON
Abstract:
We report photometric observations for comet C/2012 S1 (ISON) obtained
during the time period immediately after discovery (r=6.28AU) until it
moved into solar conjunction in mid-2013 June using the UH2.2m, and
Gemini North 8m telescopes on Mauna Kea, the Lowell 1.8m in Flagstaff,
the Calar Alto 1.2m telescope in Spain, the VYSOS-5 telescopes on
Mauna Loa Hawaii and data from the CARA network. Additional
pre-discovery data from the Pan STARRS1 survey extends the light curve
back to 2011 September 30 (r=9.4AU). The images showed a similar tail
morphology due to small micron sized particles throughout 2013.
Observations at submillimeter wavelengths using the James Clerk
Maxwell Telescope on 15 nights between 2013 March 9 (r=4.52AU) and
June 16 (r=3.35AU) were used to search for CO and HCN rotation lines.
No gas was detected, with upper limits for CO ranging between
3.5-4.5x1027molecules/s. Combined with published water production
rate estimates we have generated ice sublimation models consistent
with the photometric light curve. The inbound light curve is likely
controlled by sublimation of CO2. At these distances water is not a
strong contributor to the outgassing. We also infer that there was a
long slow outburst of activity beginning in late 2011 peaking in
mid-2013 January (r∼5AU) at which point the activity decreased again
through 2013 June. We suggest that this outburst was driven by CO
injecting large water ice grains into the coma. Observations as the
comet came out of solar conjunction seem to confirm our models.
Description:
CARA is a consortium of amateur astronomers who have developed a
standardized approach to observing comets. Photometry through a
Cousins R-filter was obtained on 46 dates (Table 2) beginning shortly
after discovery in 2012 September through 2013 May 2 with most of the
observations coming from 0.4m telescopes at the BRIXIIS Observatory
in Belgium, the Talmassons Observatory and Stazione Astronomica
Descartes in Italy.
We used the 5.3 inch Variable Young Stellar Objects Survey (VYSOS)
program robotic refractor at the Mauna Loa Observatory in Hawaii, with
an Apogee Alta U16M CCD to image the comet. Images were taken nearly
nightly from 2013 April to mid-June (Table 2). On most nights, at
least three exposures of 100s each were taken in a Sloan r'-band
filter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 78 76 CARA and VYSOS observations
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
B/comets : Database of the orbital elements of comets (Rocher, 2007)
J/A+A/575/A52 : Short-term variability comet C/2012S1 (Santos-Sanz+, 2015)
J/A+A/564/L2 : CH3OH line param. in comets ISON and Lovejoy (Agundez+, 2014)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
http://www.brucegary.net/ISON/ : Comet ISON web page
http://www.aavso.org/apass : APASS: the AAVSO photometric all-sky survey
http://www.ifa.hawaii.edu/~reipurth/VYSOS : VYSOS variable young stellar
objects survey home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" Date UT date of the observation
12- 19 A8 --- Tel Telescope used in the observation
21 I1 --- N ? Number of exposures; VYSOS observations only
23- 25 I3 s Exp ? Total exposure time; VYSOS observations only
27 A1 --- Filt [Rr] Filter used in the observation (r or R)
29- 33 F5.3 AU r [3.3/6.3] Heliocentric distance
35- 39 F5.3 AU Delta [4/6.7] Geocentric distance Δ
41- 46 F6.3 deg alpha [1.8/13.7] Solar phase angle α
48- 55 F8.3 deg TA [-175/-173] True anomaly
57- 61 F5.1 deg PASun [0/360] Position angle of antisolar vector (1)
63- 67 F5.1 deg PAv [0/360] Position angle of negative velocity
vector (1)
69- 73 F5.2 mag mag [14.6/17.7] Observed magnitude in Filt
75- 78 F4.2 mag e_mag [0.02/0.3] Uncertainty in mag
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Note (1): East of North.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 25-Mar-2015