J/A+A/622/A45 1995-2000 optical spectra of CH Cyg (Iijima+, 2019)
High-velocity equatorial mass ejections and some other spectroscopic
phenomena of the symbiotic star CH Cygni in an active stage.
Iijima T., Naito H., Narusawa S.
<Astron. Astrophys. 622, A45 (2019)>
=2019A&A...622A..45I 2019A&A...622A..45I (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Spectra, optical
Keywords: (stars:) binaries: symbiotic - (stars:) binaries: spectroscopic -
(stars:) binaries: eclipsing - stars: individual: CH Cyg
Abstract:
CH Cyg is one of the most studied symbiotic stars. Its properties,
however, are still not well known. Two main periods, about 15 years
and 750-days, are known in the photometric and spectroscopic
variations, and two models are proposed for these origins. One is a
binary system with an orbital period of 15 years consisting of a hot
component and pulsating red giant with a 750-day period. The other is
a triple system consisting of an inner symbiotic binary with an
orbital period of about 750-days and third component with an orbital
period of 15 years. Several active stages have been observed since the
1970s during which the object brightened up by ΔU=3-5mag and
prominent emission lines appeared. Large mass outflows were observed
at some active stages.
The spectral variation of CH Cyg has been monitored at Asiago
Observatories to understand the problems mentioned above. We have
analysed spectra obtained in the time period from 1995 to 2004 which
covers an active stage during the years 1998-2000.
High- and low-resolution optical spectra obtained at the Asiago
Observatories are used.
Narrow absorption lines of FeI, CrI, TiI, and so on appeared in
1998 at an early phase of the active stage. These lines are clearly
distinguished from those of the M-type giant and are typically found
on the spectrum of early A-type dwarfs. They were redshifted by about
30km/s, with respect to the absorption lines of the M-type giant.
Assuming that their radial velocities represent the orbital motion of
the hot component, its semi-amplitude is estimated to be
37.0+/60.5km/s.
Description:
The calibrated low- and high-resolution spectra of CH Cyg used in the
article are presented. The spectra are reduced with the standard tasks
of the NOAO IRAF package. The spectrophotometric calibrations are made
using the spectra of nearby standard stars HD192281 or BD+40 4032. The
wavelengths are given in the heliocentric frame. The effects of the
interstellar extinction are not corrected.
Objects:
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RA (2000) DE Designation(s)
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19 24 33.07 +50 14 29.1 CH Cyg = HD 182917
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 202 101 *List of spectra
fits/* . 101 Individual spectra
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Note on list.dat: All spectra, excepting for the last two in 2004, are used to
estimate the intensities of the emission lines in Figs. 2, 3.
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See also:
J/A+A/311/484 : CH Cyg 1991-1995 UBV-JHKLM photometry (Munari+, 1996)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
12 A1 --- DE- Declination sign (J2000)
13- 14 I2 deg DEd Declination (J2000)
16- 17 I2 arcmin DEm Declination (J2000)
19- 22 F4.1 arcsec DEs Declination (J2000)
24- 27 I4 --- Nx Number of pixels along X-axis
29- 33 I5 --- No Spectrum identification number
35- 44 A10 "YYYY/MM/DD" Obs.date Observation date
46- 50 A5 "h:m" Obs.time Observation time at start of exposure
52- 55 I4 s ExpTime Exposure time
58- 63 A6 --- Inst Instrument (1)
65- 71 F7.2 0.1nm blambda Lower value of wavelength interval
73- 79 F7.2 0.1nm Blambda Upper value of wavelength interval
81- 88 F8.6 0.1nm dlambda Spectral resolution
90- 98 F9.3 d JD Julian date (JD-2450000)
100-101 A2 Kibyte size Size of FITS file
103-118 A16 --- FileName Name of FITS file, in subdirectory fits
120-202 A83 --- Title Title of the FITS file and comments
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Note (1): Instruments as follows:
BC600 = Boller & Chivens spectrograph with a 600 groove/mm grating.
BC1200 = Boller & Chivens spectrograph with a 1200 groove/mm grating
camVI = prismatic spectrograph Camera VI
ech = Reosc Echelle spectrograph
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Acknowledgements:
Takashi Iijima, takashi.iijima(at)oapd.inaf.it
(End) Patricia Vannier [CDS] 27-Dec-2018