J/A+A/704/A233 SN2017ckj light curves and spectra (Li+, 2025)
SN2017ckj: A linearly declining Type IIb supernova with a relatively massive
hydrogen envelope.
Li L.-H., Benetti S., Cai Y.-Z., Wang B., Pastorello A., Elias-Rosa N.,
Reguitti A., Borsato L., Cappellaro E., Fiore A., Fraser M., Gromadzki M.,
Harmanen J., Isern J., Kangas T., Kankare E., Lundqvist P., Mattila S.,
Ochner P., Peng Z.-H., Reynolds T.M., Salmaso I., Srivastav S.,
Stritzinger M.D., Tomasella L., Valerin G., Wang Z.-Y., Zhang J.-J.,
Wu C.-Y.
<Astron. Astrophys. 704, A233 (2025)>
=2025A&A...704A.233L 2025A&A...704A.233L (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, ugriz ; Spectra, optical
Keywords: circumstellar matter - supernovae: general -
supernovae: individual: SN 2017ckj
Abstract:
We present optical observations of the Type IIb supernova (SN)
2017ckj, covering approximately 180 days after the explosion. Its
early-time multi-band light curves display no clear evidence of a
shock-cooling tail, resembling the behavior of SN2008ax. The V-band
light curve exhibits a short rise time of about 5 days and reaches an
absolute peak magnitude of MV=-18.58±0.17mag. The late-time
multi-band light curves reveal a linear decline. We modelled the
bolometric light curve of SN2017ckj to constrain the progenitor and
the explosion parameters. We estimated a total mass of 56Ni
synthesized by SN2017ckj of MNi=0.21+0.05-0.03M☉, with a
massive H-rich envelope of Menv=0.4+0.1-0.1M☉. Both the
56Ni mass and the envelope mass of SN2017ckj are higher than those
of typical SNe IIb, in agreement with its peculiar light curve
evolution. The early-time spectra of SN2017ckj are dominated by a blue
continuum, accompanied by narrow Halpha and HeII emission lines. The
earliest spectrum exhibits flash ionization features, from which we
estimated a progenitor mass-loss rate of ∼3.4x10-4M☉/yr. At
later epochs, the spectra develop broad P-Cygni profiles and become
increasingly similar to those of SNe IIb, especially SN2018gk. The
late-time spectrum at around 139 days does not show a distinct decline
in the strength of Halpha emission profile, also indicating a
relatively massive envelope of its progenitor. Aside from the Halpha
feature, the nebular spectrum exhibits prominent emission lines of OI,
CaII, [CaII], and MgI], which are consistent with the prototypical
SN1993J.
Description:
The multi-band photometric data and spectra for SN2017ckj.
Objects:
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RA (2000) DE Designation(s)
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16 09 44.39 +48 02 07.2 SN2017ckj = AT 2017ckj
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ugriz.dat 86 17 ugriz light curves
bv.dat 50 13 BV light curves
list.dat 113 11 List of spectra
fits/* . 11 Individual fits spectra
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Byte-by-byte Description of file: ugriz.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date
12- 19 F8.2 d MJD Modified Julian date
21 A1 --- l_umag Limit flag on umag
22- 26 F5.2 mag umag ?=0 u magnitude
28- 31 F4.2 mag e_umag ?=0 u magnitude error
33- 37 F5.2 mag gmag ?=0 g magnitude
39- 42 F4.2 mag e_gmag ?=0 g magnitude error
44- 48 F5.2 mag rmag ?=0 r magnitude
50- 54 F5.3 mag e_rmag ?=0 r magnitude error
56- 60 F5.2 mag imag ?=0 i magnitude
62- 65 F4.2 mag e_imag ?=0 i magnitude error
67- 71 F5.2 mag zmag ?=0 z magnitude
73- 76 F4.2 mag e_zmag ?=0 z magnitude error
78- 86 A9 --- Source Source
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Byte-by-byte Description of file: bv.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date
12- 19 F8.2 d MJD Modified Julian date
21 A1 --- l_Bmag Limit flag on Bmag
22- 26 F5.2 mag Bmag B magnitude
28- 31 F4.2 mag e_Bmag B magnitude error
33 A1 --- l_Vmag Limit flag on Vmag
34- 38 F5.2 mag Vmag V magnitude
40- 43 F4.2 mag e_Vmag V magnitude error
45- 50 A6 --- Source Source
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nx Number of pixels along X-axis
6 I1 --- Ny ? Number of pixels along Y-axis
8- 30 A23 "datime" Obs.date Observation date
32- 38 F7.2 0.1nm blambda Lower value of wavelength interval
40- 47 F8.2 0.1nm Blambda Upper value of wavelength interval
49- 55 F7.5 0.1nm dlambda Wavelength resolution
57- 58 I2 Kibyte size Size of FITS file
60- 80 A21 --- FileName Name of FITS file, in subdirectory fits
82-113 A32 --- Title Title of the FITS file
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Acknowledgements:
Luhan Li, liluhan(at)ynao.ac.cn
(End) Patricia Vannier [CDS] 12-Nov-2025