J/AJ/154/196 Properties of comet 49P/Arend-Rigaux, 1984-2012 (Eisner+, 2017)
The rotation and other properties of comet 49P/Arend-Rigaux, 1984-2012.
Eisner N., Knight M.M., Schleicher D.G.
<Astron. J., 154, 196 (2017)>
=2017AJ....154..196E 2017AJ....154..196E (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Comets ; Ephemerides ; Photometry, VRI ;
Abundances
Keywords: comets: individual (49P/Arend-Rigaux)
Abstract:
We analyzed images of comet 49P/Arend-Rigaux on 33 nights between 2012
January and May and obtained R-band lightcurves of the nucleus.
Through usual phasing of the data, we found a double-peaked lightcurve
having a synodic rotation period of 13.450±0.005 hr. Similarly,
phase dispersion minimization and the Lomb-Scargle method both revealed
rotation periods of 13.452 hr. Throughout the 2011/2012 apparition,
the rotation period was found to increase by a small amount, consistent
with a retrograde rotation of the nucleus. We also reanalyzed the
publicly available data from the 1984/1985 apparition by applying the
same techniques, finding a rotation period of 13.45±0.01 hr. Based
on these findings, we show that the change in rotation period is less
than 14 s per apparition. Furthermore, the amplitudes of the
lightcurves from the two apparitions are comparable, to within
reasonable errors, even though the viewing geometries differ, implying
that we are seeing the comet at a similar sub-Earth latitude. We
detected the presence of a short-term jet-like feature in 2012 March,
which appears to have been created by a short-duration burst of
activity on March 15. Production rates obtained in 2004/2005, along
with reanalysis of the previous results from 1984/1985, imply a strong
seasonal effect and a very steep fall-off after perihelion. This, in
turn, implies that a single source region, rather than leakage from
the entire nucleus, dominates activity.
Description:
Useful images of comet 49P/Arend-Rigaux were obtained on a total of
33 nights between 2012 January and May with sampling at monthly intervals
(Table 1). Observations were obtained at the Lowell Observatory Hall
1.1 m telescope with the e2v CCD231-84. On-chip 2x2 binning produced
images with a pixel scale of 0.740 arcseconds/pixel. On-chip 3x3 binning
was used for the observations in May, producing images with a pixel scale
of 1.11 arcseconds/pixel.
Additional observations were obtained with the 0.8 m telescope, also
at Lowell Observatory, with the e2v CCD42-40. On-chip 2x2 binning produced
images with a pixel scale of 0.456 arcseconds/pixel.
Broadband R-filters were used for all observations, except for those
carried out in May, which used the VR-filter (about twice as wide as a
standard R-filter), in order to improve the signal-to-noise ratio.
Exposure times prior to 2012 March 21 were typically 120 s; exposure
times thereafter were always 300 s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 39 *Summary of Comet 49P/Arend-Rigaux Observations
and Geometric Parameters during Our 2012
Observations
table2.dat 31 4722 Table of CCD Photometry
table4.dat 77 10 Photometry Observing Circumstances and
Fluorescence Efficiencies for Comet
49P/Arend-Rigaux
table5.dat 110 13 Photometric Fluxes and Aperture Abundances for
Comet 49P/Arend-Rigaux
table6.dat 123 13 Photometric Production Rates for Comet
49P/Arend-Rigaux
table7.dat 23 148 Dates, Times, and Magnitudes Extracted from
Wisniewski et al. (1986acm..proc..337W) for
the 1985 Observations
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Note on table1.dat: All parameters were taken at the midpoint of each night's
observations, and all images were obtained at Lowell Observatory.
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See also:
B/comets : Database of the orbital elements of comets (Rocher, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "date" Date Observation date (UT) (YYYY-MMM-DD)
13- 17 A5 "h:m" Start Start time of observation (UT)
19- 23 A5 "h:m" End End time of observation (UT)
25- 30 F6.2 d DT [98.22/208.15] Time since perihelion
(2011 October 19.1) {Detla}T
32- 34 F3.1 m Diam [0.8/1.1] Telescope diameter
36- 40 F5.3 AU rH [1.774/2.507] Heliocentric distance rH
42- 46 F5.3 AU Delta [1.027/1.964] Geocentric distance Δ
48- 52 F5.1 deg PA [0.2/358] Position angle of the Sun
54- 57 F4.1 deg alpha [13.4/27.7] Solar phase angle α
59- 63 F5.3 h Dt [0.142/0.272] Light travel time Δt
65- 70 F6.3 mag Dm1 [-4.345/-2.214] Magnitude necessary to correct
for changes in the geometry
(Δm1=-5log(rhΔ)-αβ)
72- 77 F6.3 mag Dm2 [-0.115/0.293] Offset necessary to make the data
on all nights peak at the same magnitude, after
correcting for geometry
79- 84 F6.4 --- sigma(m) [0.0016/0.0058] Average uncertainty calculated
for the night σm
86- 88 F3.1 arcsec Rad [1.6/4.6] Radius of the aperture used to extract
the lightcurves (see Section 2.3)
90-108 A19 --- Weather Weather conditions
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Observation date (UT) (YYYY-MM-DD)
12- 17 F6.3 h Time [2.643/13.672] Fractional UT time at midpoint of
the exposure, uncorrected for light travel time
19- 19 I1 --- Tel [1/2] Telescope used (1)
21- 25 F5.2 mag Rmag [16.09/18.75] Observed R-band magnitude (2)
27- 31 F5.2 mag Rmag-c [12.79/14.71] Observed R-band magnitude corrected
(3)
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Note (1): Telescope are defined as follows:
1 = Lowell Observatory 0.8m telescope;
2 = Lowell Observatory Hall 1.1m telescope.
Note (2): Observed magnitude after applying absolute calibrations, extinction
corrections, and comparison star corrections. Broadband R-filters were used
for all observations except those carried out in May, which used the VR-filter
(about twice as wide as a standard R-filter) in order to improve the
signal-to-noise.
Note (3): Observed R-band magnitude corrected by Δm2 (given in Table 1)
so that all nights have the same peak magnitude.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Date Observation date (UT) (YYYY-MMM-DD.dd)
16- 21 F6.2 d DT [-75.88/76.28] Time since perihelion {Detla}T
23- 27 F5.3 AU rH [1.375/1.664] Heliocentric distance rH
29- 33 F5.3 AU Delta [0.59/1.506] Geocentric distance Δ
35- 38 F4.1 deg alpha [4.6/43.2] Solar phase angle α
40- 44 F5.2 [-] logA [0.08/0.45] Phase adjustment
logA(0°)fρ (1)
46- 49 F4.1 km/s Vel [-9.8/8.9] Velocity
51- 57 F7.3 [10-7W] logL/N(OH) [-15.07/-14.889] Fluorescence efficiency
for OH (in erg/s/molecule) (2)
59- 65 F7.3 [10-7W] logL/N(NH) [-13.514/-13.355] Fluorescence efficiency
for NH (in erg/s/molecule) (2)
67- 73 F7.3 [10-7W] logL/N(CN) [-12.876/-12.654] Fluorescence efficiency
for CN (in erg/s/molecule) (2)
75- 77 F3.1 m Diam [1.1/2.2] Telescope diameter
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Note (1): Adjustment to 0° solar phase angle of the A(θ)fρ values
based on assumed phase function (see the text).
Note (2): Fluorescence efficiencies are for rH=1 au and are scaled by
rH-2 in the reductions.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Date Observation date (UT) (YYYY-MMM-DD.dd)
16- 19 F4.1 arcsec Ap [20/97.2] Aperture size
21- 24 F4.2 km log(rho) [3.63/4.59] Log aperture size
26- 31 F6.2 [mW/m2] logF(OH) [-11.92/-11.27]? Log emission band
flux for OH (in erg/cm2/s)
33- 38 F6.2 [mW/m2] logF(NH) [-13.37/-11.9]? Log emission band flux
for NH (in erg/cm2/s)
40- 45 F6.2 [mW/m2] logF(CN) [-12.73/-11.46]? Log emission band
flux for CN (in erg/cm2/s)
47- 52 F6.2 [mW/m2] logF(C3) [-12.46/-11.53]? Log emission band
flux for C3 (in erg/cm2/s)
54- 59 F6.2 [mW/m2] logF(C2) [-13/-11.58] Log emission band flux
for C2 (in erg/cm2/s)
61- 66 F6.2 [10-2W/m2/nm] logF(UV) [-15.61/-14.13]? Log continuum flux in
UV filter (in erg/cm2/s/Å) (G1)
68- 73 F6.2 [10-2W/m2/nm] logF(B) [-14.57/-13.97]? Log continuum flux in
blue filter (in erg/cm2/s/Å)
(G1)
75- 80 F6.2 [10-2W/m2/nm] logF(G) [-14.59/-13.8] Log continuum flux in
green filter (in erg/cm2/s/Å)
(G1)
82- 86 F5.2 [-] logM(rho)OH [29.99/31.36]? OH aperture abundance
(in molecule)
88- 92 F5.2 [-] logM(rho)NH [27.04/29.2]? NH aperture abundance
(in molecule)
94- 98 F5.2 [-] logM(rho)CN [26.98/28.99]? CN aperture abundance
(in molecule)
100-104 F5.2 [-] logM(rho)C3 [26.92/28.44]? C3 aperture abundance
(in molecule)
106-110 F5.2 [-] logM(rho)C2 [26.73/28.74]? C2 aperture abundance
(in molecule)
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Date Observation date (UT) (YYYY-MMM-DD.dd)
16- 21 F6.2 d DT [-75.89/76.28] Time since perihelion {Detla}T
23- 27 F5.3 [AU] log(rH) [0.138/0.221] Log heliocentric distance
29- 32 F4.2 [km] log(rho) [3.63/4.59] Log aperture size
34- 38 F5.2 [s-1] logQ(OH) [26.79/27.45]? OH production rate
(in molecule/s)
40- 43 F4.2 [s-1] E_logQ(OH) [0.03/0.13]? Upper limit uncertainty
in logQ(OH) (1)
45- 49 F5.2 [s-1] logQ(NH) [24.04/25.18]? NH production rate
(in molecule/s)
51- 54 F4.2 [s-1] E_logQ(NH) [0.01/0.17]? Upper limit uncertainty
in logQ(NH) (1)
56- 60 F5.2 [s-1] logQ(CN) [23.95/24.64]? CN production rate
(in molecule/s)
62- 65 F4.2 [s-1] E_logQ(CN) [0.02/0.08]? Upper limit uncertainty
in logQ(CN) (1)
67- 71 F5.2 [s-1] logQ(C3) [23.53/24.38] C3 production rate
(in molecule/s)
73- 76 F4.2 [s-1] E_logQ(C3) [0/0.16] Upper limit uncertainty in logQ(C3)
(1)
78- 82 F5.2 [s-1] logQ(C2) [1.73/24.58]? C2 production rate
(in molecule/s)
84- 87 F4.2 [s-1] E_logQ(C2) [0.04/0.14]? Upper limit uncertainty
in logQ(C2) (1)
89- 92 F4.2 [cm] logA(UV) [0.64/1.93]? Now standard proxy for dust
production in UV filter (G1)
94- 97 F4.2 [cm] E_logA(UV) [0.02/0.54]? Upper limit uncertainty
in logA(UV) (1)
99-102 F4.2 [cm] logA(B) [1.1/1.94]? Now standard proxy for dust
production in blue filter (G1)
104-107 F4.2 [cm] E_logA(B) [0.01/0.16]? Upper limit uncertainty
in logA(B) (1)
109-112 F4.2 [cm] logA(G) [1.06/1.99]? Now standard proxy for dust
production in green filter (G1)
114-117 F4.2 [cm] E_logA(G) [0.01/0.14]? Upper limit uncertainty
in logA(G) (1)
119-123 F5.2 [-] logQ(H2O) [26.82/27.5]? Water production rate
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Note (1): Production rates and now standard proxy for dust production are
followed by the upper, i.e., the positive, uncertainty. The "+" and
"-" uncertainties are equal as percentages, but unequal in log space;
the "-" values can be computed.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "date" Date Observation date (UT) (YYYY-MMM-DD)
13- 17 F5.2 h Time [2.16/12.18] Fractional UT time
19- 23 F5.3 mag mag [5.72/6.328] Magnitude from Wisniewski et al.
(1986acm..proc..337W)
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Global notes:
Note (G1): Continuum filter wavelengths:
UV(1984/1985)=3650Å, UV (2004/2005)=3445Å;
blue(2004/2005)=4450Å;
green(1984/1985)=4845Å, green(2004/2005)=5260Å.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 30-Jul-2018