J/ApJ/909/176 SN2017hpa carbon-rich type Ia LCs and sp. (Zeng+, 2021)
SN 2017hpa: a nearby carbon-rich type Ia supernova with a large velocity
gradient.
Zeng X., Wang X., Esamdin A., Pellegrino C., Zheng W., Zhang J., Mo J.,
Li W., Howell D.A., Filippenko A.V., Lin H., Brink T.G., Baron E.A.,
Burke J., DerKacy J.M., McCully C., Hiramatsu D., Hosseinzadeh G.,
Jeffers B.T., Ross T.W., Stahl B.E., Stegman S., Valenti S., Wang L.,
Xiang D., Zhang J., Zhang T.
<Astrophys. J., 909, 176 (2021)>
=2021ApJ...909..176Z 2021ApJ...909..176Z
ADC_Keywords: Supernovae; Photometry, UBVRI; Spectra, optical
Keywords: Supernovae ; Type Ia supernovae
Abstract:
We present extensive, well-sampled optical and ultraviolet photometry
and optical spectra of the Type Ia supernova (SN Ia) 2017hpa. The
light curves indicate that SN 2017hpa is a normal SN Ia with an
absolute peak magnitude of MmaxB~-19.12±0.11mag and a postpeak
decline rate Δm15(B)=1.02±0.07mag. According to the
quasi-bolometric light curve, we derive a peak luminosity of
1.25x1043erg/s and a 56Ni mass of 0.63±0.02M☉. The
spectral evolution of SN 2017hpa is similar to that of normal Ia
supernovae (SNe Ia), while it exhibits an unusually rapid velocity
evolution resembling that of SN 1991bg-like SNe Ia or the high-
velocity subclass of SNe Ia, with a postpeak velocity gradient of
∼130±7km/s/d. Moreover, its early spectra (t<-7.9d) show a
prominent CIIλ6580 absorption feature, which disappeared in
near-maximum-light spectra but reemerged at phases from t~+8.7d to
t~+11.7d after maximum light. This implies that some unburned carbon
may mix deep into the inner layer and is supported by the low
CIIλ6580-to-SiIIλ6355 velocity ratio (∼0.81) observed in
SN 2017hpa. The OIλ7774 line shows a velocity distribution like
that of carbon. The prominent carbon feature, the low velocity seen in
carbon and oxygen, and the large velocity gradient make SN 2017hpa
stand out from other normal SNe Ia and are more consistent with
predictions from a violent merger of two white dwarfs. Detailed
modeling is still needed to reveal the nature of SN 2017hpa.
Description:
After the discovery of SN 2017hpa on 2017 October 25.35, we triggered
follow-up photometric observations on several telescopes, including
the 0.8m Tsinghua-NAOC telescope (TNT), the Las Cumbres Observatory
(LCO) Telescope network, the 0.76m Katzman Automatic Imaging Telescope
(KAIT) at Lick Observatory, and the 1m Nickel reflector at Lick
Observatory. The TNT, Nickel, and KAIT monitored SN 2017hpa in the
BVRI bands, while the LCO 1m telescope sampled its light curves in the
BVgri bands. Optical and ultraviolet (UV) observations of SN 2017hpa
were also obtained with the Neil Gehrels Swift Observatory.
A total of 26 low-resolution optical spectra of SN 2017hpa have been
obtained using different telescopes and equipment, including the AFOSC
mounted on the Asiago Ekar telescope, the BFOSC mounted on the
Xinglong 2.16m telescope (XLT), the YFOSC on the Lijiang 2.4m
telescope (LJT) of Yunnan Astronomical Observatories, the Kast
spectrograph on the Lick 3m Shane telescope, and the LCO 2m Faulkes
Telescope North. The journal of spectroscopic observations is
presented in Table 4.
Objects:
-----------------------------------------------------
RA (ICRS) DE Designation(s)
-----------------------------------------------------
04 39 50.75 +07 03 54.9 SN 2017hpa = SN 2017hpa
-----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 127 184 Photometric observations of SN 2017hpa
by ground-based telescopes
table4.dat 88 26 Spectroscopic observations of SN 2017hpa
sp/* . 26 Optical spectra in ASCII format
(data behind Figure 10)
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See also:
II/183 : UBVRI Photometric Standards (Landolt 1992)
VIII/77 : HI spectral properties of galaxies (Springob+, 2005)
J/ApJ/645/488 : SN type Ia luminosities (Wang+, 2006)
J/A+A/471/527 : Spectroscopy of SN 2005cf (Garavini+, 2007)
J/MNRAS/377/1531 : Optical & IR photometry of SN 2004eo (Pastorello+, 2007)
J/ApJ/699/L139 : Spectral parameters of SNe Ia (Wang+, 2009)
J/ApJS/190/418 : Light curves for 165 SNe (Ganeshalingam+, 2010)
J/ApJ/742/89 : Relations between sp. and colors of SNe Ia (Foley+, 2011)
J/MNRAS/410/585 : SN 2009dc BVRI light curves (Silverman+, 2011)
J/AJ/143/126 : Sp. of 462 nearby Type Ia supernovae (Blondin+, 2012)
J/ApJ/745/74 : Pre-maximum spectra of type Ia SNe (Folatelli+, 2012)
J/MNRAS/425/1789 : Berkeley supernova Ia program. I. (Silverman+, 2012)
J/MNRAS/425/1819 : Berkeley supernova Ia program. II. (Silverman+, 2012)
J/other/NewA/20.30 : BVRI light curves of 3 SN (Munari+, 2013)
J/other/Sci/340.170 : Classifications of 188 SNe Ia (Wang+, 2013)
J/A+A/568/A22 : Joint analysis of SDSS-II & SNLS SNe Ia (Betoule+, 2014)
J/MNRAS/444/3258 : Velocities and EW of PTF SNe Ia (Maguire+, 2014)
J/MNRAS/452/4307 : From optical to IR photometry of SN 2013dy (Pan+, 2015)
J/MNRAS/451/1973 : Type Ia SNe igh-velocity features (Silverman+, 2015)
J/ApJS/220/20 : Si and Ca high-velocity features in SNe Ia (Zhao+, 2015)
J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)
J/AJ/151/125 : Optical and UV photometry of SN 2013dy (Zhai+, 2016)
J/ApJ/869/56 : Updated calibration of CSP-I SNe Ia sample (Burns+, 2018)
J/ApJ/877/152 : UV-NIR light curves of type Ia SN 2017erp (Brown+, 2019)
J/ApJ/882/120 : CfA, CSP, BSP & LOSS sp. & phot. of SNe Ia (Wang+, 2019)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.2 d MJD [58053.34/58210.16] Modified Julian Date
of observation (JD-2400000.5)
10- 16 F7.2 d Epoch [-13.3/143.52] Epoch (1)
18- 23 F6.3 mag Bmag [15.42/20.3]? B-band AB magnitude
25- 29 F5.3 mag e_Bmag [0.012/0.5]? Uncertainty in Bmag
31- 36 F6.3 mag Vmag [15.32/20]? V-band AB magnitude
38- 42 F5.3 mag e_Vmag [0.008/0.5]? Uncertainty in Vmag
44- 49 F6.3 mag Rmag [15.25/20.51]? R-band AB magnitude
51- 55 F5.3 mag e_Rmag [0.009/0.5]? Uncertainty in Rmag
57- 62 F6.3 mag Imag [15.55/19.7]? I-band AB magnitude
64- 68 F5.3 mag e_Imag [0.013/0.5]? Uncertainty in Imag
70- 75 F6.3 mag gmag [15.32/19.41]? g-band AB magnitude
77- 81 F5.3 mag e_gmag [0.02/0.4]? Uncertainty in gmag
83- 88 F6.3 mag rmag [15.28/19.51]? r-band AB magnitude
90- 94 F5.3 mag e_rmag [0.05/0.2]? Uncertainty in rmag
96-101 F6.3 mag imag [15.76/22.5]? i-band AB magnitude
103-107 F5.3 mag e_imag [0.04/0.4]? Uncertainty in imag
109-114 F6.3 mag Clear [14.99/19.11]? Clear AB magnitude (2)
116-120 F5.3 mag e_Clear [0.013/0.4]? Uncertainty in Clear
122-127 A6 --- Tel Telescope (3)
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Note (1): Relative to the epoch of B-band maximum brightness (MJD=58066.6).
Note (2): The clear band is close to broadband R.
Note (3): Telescope code as follows:
KAIT4 = 0.76m Katzman Automatic Imaging Telescope, Lick Observatory
(BVRI bands);
LCO = Las Cumbres Obervatory Telescope network (BVgri bands);
Nickel = 1m Nickel reflector, Lick Observatory (BVRI bands);
TNT = 0.8m Tsinghua-NAOC telescope (BVgri bands).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.2 d MJD [58052.5/58153.3] Modified Julian Date
10- 15 F6.2 yr Epoch [-14.12/86.63] Epoch of observation relative
to the epoch of B-band maximum (MJD=58066.6)
17- 20 I4 0.1nm lam1 [3249/5896] Wavelength, start
22- 26 I5 0.1nm lam2 [8182/10400] Wavelength, end
28- 42 A15 --- Inst Instrument (Asiago, LCO, LJT, Lick 3m or XLT)
44- 88 A45 --- FileName Name of the ASCII file in subdirectory "sp";
column added by CDS
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Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.5 0.1nm lambda [3249/10400] Spectrum wavelength,
in Angstrom units
13- 35 E23.18 mW/m2 Flux [-2.4e-15/7.4e-14] Flux, in erg/s/cm2 units
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Aug-2022