J/A+A/699/A81 EI Psc optical and infrared spectra (Kara+, 2025)
Hot donors in cataclysmic variables: The case of EI Psc.
Kara J., Zharikov S., Wolf M., Vaidman N., Agishev A., Khokhlov S.,
Chavez C.E.
<Astron. Astrophys. 699, A81 (2025)>
=2025A&A...699A..81K 2025A&A...699A..81K (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, cataclysmic ; Spectra, optical ; Spectra, infrared
Keywords: stars: dwarf novae - stars: fundamental parameters - novae -
cataclysmic variables
Abstract:
We present results of time-resolved optical spectroscopy and
photometry of the short-orbital period dwarf nova EI Psc.
This study aims to determine fundamental system parameters of EI Psc,
study properties of accretion structures in the system, and
investigate its origin and current evolution state.
We analyse newly obtained time-resolved spectroscopic and photometric
observations as well as archival data. We used light curve modelling,
Doppler tomography, and MESA evolutionary models to study the
characteristics of EI Psc.
The system contains a relatively low temperature (Teff=6130K) white
dwarf with mass of MWD=0.70(4)M☉. The mass of the warm
(T2=4440K) secondary is M2=0.13M☉. The inclination of the
system is i=44.5°(7). The mass accretion rate is
∼4x10-13M☉_/yr^. The long-term light curve of the system shows
outbursts and superoutbursts. The quiescence light curve is
double-humped and is formed by the combination of radiation from the
Roche lobe filling the hot secondary and the hot spot. The radius of
the outer disc is about two times smaller than the tidal truncation
radius. Most of the disc's emission consists of emission lines and
radiation from the hot spot at the stream-disc impact region.
These types of systems are formed from progenitors with a low mass WD
MWD≲0.6M☉ and relatively massive secondaries 1.1-1.5M☉
with initial orbital periods on a scale of days. The number of similar
systems is expected to be significantly lower than the usual CVs due
to a lower forming rate of their relatively massive progenitors.
Description:
New time-resolved spectroscopy was obtained with the 10.4m telescope
of the Observatorio Roque de los Muchachos (Gran Telescopio Canarias,
GTC) using the OSIRIS instrument2 in the long-slit mode on the nights
of 2023 September 4, 5, and 7 (programme: GTC2-23BMEX3).
On the first night, we used the grism R2500I (7330-10000Å), on the
second R2500R (5575-7685Å), and on the third R2500V
(4500-6000Å), which gave an R∼2500 resolution. In each
observational run, we obtained 29 spectra with an individual exposure
time of 181 s, allowing us to cover about 120 min, just under the
length of two orbital periods. The standard IRAF procedure was used to
reduce the data.
Spectra obtained at GTC and the photometry obtained at OAN SPM.
Objects:
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RA (2000) DE Designation(s)
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23 29 54.21 +06 28 11.5 EI Psc = WISE J232954.19+062812.0
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 52 86 List of spectra
sp/* . 86 Individual spectra with exposition time 181s
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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- 18 F18.10 d HJD Heliocentric Julian date
23- 52 A30 --- FileName Name of the spectrum file in subdirectory sp
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 20 F20.13 0.1nm lambda Wavelength
22- 40 F19.14 --- Flux Normalized flux
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Acknowledgements:
Jan Kara, honza.kara.7(at)gmail.com
(End) Patricia Vannier [CDS] 28-May-2025