J/ApJ/922/L10 NIR spectra of Nova V1674 Herculis (Woodward+, 2021)
Near-infrared studies of Nova V1674 Herculis: a shocking record breaker.
Woodward C.E., Banerjee D.P.K., Geballe T.R., Page K.L., Starrfield S.,
Wagner R.M.
<Astrophys. J., 922, L10 (2021)>
=2021ApJ...922L..10W 2021ApJ...922L..10W
ADC_Keywords: Novae; Spectra, infrared
Keywords: Classical novae ; Chemical abundances ; Spectroscopy ;
Explosive nucleosynthesis
Abstract:
We present near-infrared spectroscopy of Nova Herculis 2021
(V1674 Her), obtained over the first 70 days of its evolution. This
fastest nova on record displays a rich emission line spectrum,
including strong coronal line emission with complex structures. The
hydrogen line fluxes, combined with a distance of 4.7-1.0+1.3kpc,
give an upper limit to the hydrogen ejected mass of
Mej=1.4-1.2+0.8x10-3M☉. The coronal lines appeared at
day 11.5, the earliest onset yet observed for any classical nova,
before there was an obvious source of ionizing radiation. We argue
that the gas cannot be photoionized, at least in the earliest phase,
and must be shocked. Its temperature is estimated to be 105.57±0.05K
on day 11.5. Tentative analysis indicates a solar abundance of
aluminum and an underabundance of calcium, relative to silicon, with
respect to solar values in the ejecta. Further, we show that the
vexing problem of whether collisional ionization or photoionization is
responsible for coronal emission in classical novae can be resolved by
correlating the temporal sequence in which the X-ray supersoft phase
and the near-infrared coronal line emission appear.
Description:
Spectra of V1674 Her were obtained with SpeX on the 3.2m NASA IRTF.
The observational log (spanning 2021-Jun-18.54 to 2021-Aug-20.28)
is presented in Table 1.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
18 57 30.98 +16 53 39.5 V1674 Her = NOVA Her 2021
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 92 10 *Observational log V1674 Her
sp/* . 10 Reduced spectra in ASCII format
(Data behind Figure 2)
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Note on table1.dat: The IRTF files are the flux calibrated, order-merged output
from the XMERGEORDERS package of SpexTool reduction package (see
Cushing, M. C., Vacca, W. D., and Rayner, J. T. 2004, PASP, 116, 362.
doi:10.1086/382907). Merging and scaling of the IRTF SXD and LXD files
can be performed by the user if necessary using the IRTF SXD and LXD
files and the XMERGEXD package of SpexTool.
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
VI/64 : Recombination line intensities for hydrogenic ions (Storey+ 1995)
J/A+A/453/635 : Modelling Galactic Interstellar Extinction (Marshall+, 2006)
J/AJ/140/34 : Classification of nova light curves (Strope+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 yr Obs.Y Year of the observation
6- 8 A3 "month" Obs.M Month of the observation
10- 14 F5.2 d Obs.D Decimal day of the observation
16- 22 F7.3 d MJD [383.544/446.284] Modified Julian Date;
MJD-59000
24- 28 F5.2 d Day [5.64/68.32] Day relative to
t0=June 12.96 UT (MJD59377.96)
30- 34 A5 --- Mode SpeX mode (1)
36 A1 --- f_Mode Flag on spectra (2)
38- 41 I4 s Exp [356/1977] Total on-source integration time
on the nova
43- 46 F4.2 --- Airmass [1.01/1.65] Average airmass
48- 55 A8 --- StdName Standard HD name
57- 92 A36 --- FileName Name of the ASCII file in subdirectory "sp";
column added by CDS
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Note (1): All SpeX spectra were obtained with a 0.5"x15.0" slit (widthxlength),
yielding an effective spectral resolution R=1200. The slit was set to
the parallactic angle at the time of observations.
There are two panels covering the wavelength ranges 0.7-2.5um and
1.8-4.1um, corresponding to the SpeX short-cross dispersed ("SXD")
and long-cross dispersed ("LXD") wavelength ranges, respectively.
Note (2): Flag on spectra as follows:
e = Observed with Gemini North/GNIRS SXD, 0.45" slit R=1200.
s = The IRTF files for SXD 20210820 (day 68.32) and LXD
files for 2021070 (day 24.39) and 20210802 (day 50.42) have smoothed
using a Savitzky-Golay filter using a SG window=7.5 and degree=2.
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Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 E13.8 um lambda [0.69/4.2] Wavelength
15- 28 E14.9 W/m2/um S [-9.9e-12/9.7e-11] Flux density;
uncorrected for reddening
30- 42 E13.8 W/m2/um e_S [4.2e-18/1.1e-10]? Uncertainty in S;
generated by the pipeline reduction
algorithms
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 31-Mar-2023