J/AJ/154/45 WINERED CN-red band emission in comet C/2013 R1 (Shinnaka+, 2017)
Near-infrared spectroscopic observations of comet C/2013 R1 (Lovejoy)
by WINERED: CN red-system band emission.
Shinnaka Y., Kawakita H., Kondo S., Ikeda Y., Kobayashi N., Hamano S.,
Sameshima H., Fukue K., Matsunaga N., Yasui C., Izumi N., Mizumoto M.,
Otsubo S., Takenaka K., Watase A., Kawanishi T., Nakanishi K., Nakaoka T.
<Astron. J., 154, 45-45 (2017)>
=2017AJ....154...45S 2017AJ....154...45S (SIMBAD/NED BibCode)
ADC_Keywords: Comets ; Spectra, infrared
Keywords: comets: general - comets: individual: C/2013 R1 (Lovejoy) -
instrumentation: spectrographs
Abstract:
Although high-resolution spectra of the CN red-system band are
considered useful in cometary sciences, e.g., in the study of isotopic
ratios of carbon and nitrogen in cometary volatiles, there have been
few reports to date due to the lack of high-resolution
(R=λ/Δλ>20000) spectrographs in the near-infrared
region around ∼1 µm. Here, we present the high-resolution emission
spectrum of the CN red-system band in comet C/2013 R1 (Lovejoy),
acquired by the near-infrared high-resolution spectrograph WINERED
mounted on the 1.3 m Araki telescope at the Koyama Astronomical
Observatory, Kyoto, Japan. We applied our fluorescence excitation
models for CN, based on modern spectroscopic studies, to the observed
spectrum of comet C/2013 R1 (Lovejoy) to search for CN isotopologues
(13C14N and 12C15N). We used a CN fluorescence excitation
model involving both a "pure" fluorescence excitation model for the
outer coma and a "fully collisional" fluorescence excitation model for
the inner coma region. Our emission model could reproduce the observed
12C14N red-system band of comet C/2013 R1 (Lovejoy). The derived
mixing ratio between the two excitation models was
0.94(+0.02/-0.03):0.06(+0.03/-0.02), corresponding to the radius of
the collision-dominant region of ∼800-1600 km from the nucleus. No
isotopologues were detected. The observed spectrum is consistent, within
error, with previous estimates in comets of 12C/13C (∼90) and
14N/15N (∼150).
Description:
High-resolution spectroscopic observations of comet C/2013 R1 (Lovejoy;
hereafter, comet Lovejoy) in the near-infrared wavelength region were
performed using the WINERED spectrograph (Ikeda et al. 2016SPIE.9908E..5ZI)
mounted on the Nasmyth focus of the 1.3 m Araki telescope (F/10) at Koyama
Astronomical Observatory, Japan (Yoshikawa et al. 2012SPIE.8444E..6GY).
We used a slit of length 47" and width 1.5". This slit width corresponds
to a spectral resolving power of R=28000 (two pixels). The observations
of comet Lovejoy were performed on 2013 November 30, from 19:08 UT to
21:04 UT; the total integration time was 6000 s on source. The heliocentric
and geocentric distances were 0.91 au and 0.49 au, respectively, and
the relative velocities of the comet to the Sun and observer were
-14.5 km/s and 25.8 km/s, respectively, at the observations. We put
the comet at the center of the slit during the exposures. Other calibration
data (darks, flats, and comparison-lamp frames) were also acquired.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 111 210 List of Measured Lines of the CN-red (0-0) Band
in C/2013 R1 (Lovejoy) Taken By the Araki
Telescope/WINERED
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See also:
J/A+A/564/L2 : CH3OH line parameters in comets ISON and Lovejoy
(Agundez+, 2014)
J/A+A/566/L5 : C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy) spectra
(Biver+, 2014)
J/A+A/589/A78 : C/2012 F6 (Lemmon) and C/2013 R1 spectra (Lovejoy)
(Biver+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 F8.2 0.1nm lambdaO [10886.53/11107.53]? Observed wavelength in
vacuum (Å)
9 A1 --- n_lambdaO [u] Note on lambdaO (1)
11- 15 F5.2 --- Ifull [0.32/73.3]? Measured intensity for the
full-aperture extraction (arbitrary units) (2)
17- 20 F4.2 --- e_Ifull [0.45/4.7]? Uncertainty in Ifull
22- 26 F5.2 --- Ismall [0.19/44.52]? Measured intensity for the
small-aperture extraction (arbitrary units)
(3)
28- 31 F4.2 --- e_Ismall [0.25/1.9]? Uncertainty in Ismall
33- 42 F10.4 0.1nm lambdaL [10886.5/11107.5268] Wavelength in laboratory
in vacuum (Å)
44- 57 A14 --- Line Line assignment
59- 68 F10.4 cm-1 Eup [9094.3176/10231.116] Upper level energy
70- 78 F9.4 cm-1 Elow [0/1132.26] Lower level energy
80- 84 F5.3 --- Tell [0.157/0.484] Telluric transmittance
86- 93 E8.3 ph/s FluoEq Fluorescence equilibrium
95-102 E8.3 ph/s FluoEff1 Fluorescence efficiency (Boltzmann distribution
for Trot=100 K)
104-111 E8.3 ph/s FluoEff2 Fluorescence efficiency (Boltzmann distribution
for Trot=282 K)
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Note (1): Note as follows:
u = Indicates unmeasurable lines due to overlap of CN lines with strong OH
airglows.
Note (2): The aperture size at the comet was 530x17000 km.
Note (3): The aperture size at the comet was 530x2200 km.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 30-May-2018