J/A+A/676/A98 EG And RV and fluxes for 10 FeI lines (Shagatova+, 2023)
Density asymmetry and wind velocities in the orbital plane of the
symbiotic binary EG Andromedae.
Shagatova N., Skopal A., Kundra E., Komzik R., Shugarov S.Y., Pribulla T.,
Krushevska V.
<Astron. Astrophys., 676, A98 (2023)>
=2023A&A...676A..98S 2023A&A...676A..98S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Stars, giant ; Radial velocities ; Optical
Keywords: binaries: symbiotic - stars: late-type - stars: individual: EG And -
stars: atmospheres - stars: winds, outflows - line: profiles
Abstract:
Non-dusty late-type giants without a corona and large-scale pulsations
represent objects that do not fulfil the conditions under which
standard mass-loss mechanisms can be applied efficiently. Despite the
progress during the past decades, the driving mechanism of their winds
is still unknown.
One of the crucial constraints of aspiring wind-driving theories can
be provided by the measured velocity and density fields of outflowing
matter. The main goal of this work is to match the radial velocities
of absorbing matter with a depth in the red giant (RG) atmosphere in
the S-type symbiotic star EG And.
We measured fluxes and radial velocities of ten FeI absorption lines
from spectroscopic observations with a resolution of ∼30000. At
selected orbital phases, we modelled their broadened profiles,
including all significant broadening mechanisms.
The selected Fe I absorption lines at 5151-6469Å originate at a
radial distance ∼1.03RG radii from its centre. The corresponding
radial velocity is typically ∼1km/s, which represents a few
percent of the terminal velocity of the RG wind. The high scatter of
the radial velocities of several km/s in the narrow layer of the
stellar atmosphere points to the complex nature of the near-surface
wind mass flow. The average rotational velocity of 11km/s implies
that the rotation of the donor star can contribute to observed
focusing the wind towards the orbital plane. The orbital variability
of the absorbed flux indicates the highest column densities of the
wind in the area between the binary components, even though the
absorbing neutral material is geometrically more extended from the
opposite side of the giant. This wind density asymmetry in the orbital
plane region can be ascribed to gravitational focusing by the white
dwarf companion.
Our results suggest that both gravitational and rotational focusing
contribute to the observed enhancement of the RG wind towards the
orbital plane, which makes mass transfer by the stellar wind highly
efficient.
Description:
We collected 53 spectroscopic observations from Skalnate Pleso
Observatory (SP) from 2016 to 2023 in the wavelength range
4200-7300Å (Table A.1 or A.2). The observatory is equipped with a
1.3m Nasmyth-Cassegrain telescope (f/8.36) with a fibre-fed echelle
spectrograph (R∼30000) similar to the MUSICOS design. The spectra were
reduced with the Image Reduction and Analysis Facility (IRAF) using
specific scripts and programs (Pribulla et al., 2015AN....336..682P 2015AN....336..682P).
The spectra were wavelength-calibrated using the ThAr hollow-cathode
lamp. The achieved accuracy for our set of spectra corresponds to the
systematic error of RV measurements, which typically is in the range
0.2-0.6km/s.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
00 44 37.18 +40 40 45.7 EG And = HD 4174
---------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 122 53 Radial velocities of ten FeI absorption lines
from our 53 spectra (Sect. 3.1)
tablea2.dat 92 53 Absorbed fluxes of ten FeI absorption lines
from our 53 spectra (Sect. 3.1)
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.3 d HJD Heliocentric Julain date
13- 26 A14 "date" Obs.date Observation date (UT, YYYY/MM/DD.ddd)
28- 32 F5.3 --- Phase Orbital phase according to Eq. (1) of the paper
34- 41 F8.3 km/s RV5151 FeI 5151Å absorption line radial velocity
43- 50 F8.3 km/s RV5340 FeI 5340Å absorption line radial velocity
52- 59 F8.3 km/s RV5371 FeI 5371Å absorption line radial velocity
61- 68 F8.3 km/s RV5406 FeI 5406Å absorption line radial velocity
70- 77 F8.3 km/s RV5430 FeI 5430Å absorption line radial velocity
79- 86 F8.3 km/s RV5435 FeI 5435Å absorption line radial velocity
88- 95 F8.3 km/s RV5501 FeI 5501Å absorption line radial velocity
97-104 F8.3 km/s RV5507 FeI 5507Å absorption line radial velocity
106-113 F8.3 km/s RV6412 FeI 6412Å absorption line radial velocity
115-122 F8.3 km/s RV6469 FeI 6469Å absorption line radial velocity
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 11 F11.3 d HJD Heliocentric Julian date
13- 26 A14 "date" Obs.date Observation date (UT, YYYY/MM/DD.ddd)
28- 32 F5.3 --- Phase Orbital phase according to Eq. (1) of
the paper
34- 38 F5.3 10-15W/m2 F5151 FeI 5151Å absorption line absorbed flux
40- 44 F5.3 10-15W/m2 F5340 FeI 5340Å absorption line absorbed flux
46- 50 F5.3 10-15W/m2 F5371 FeI 5371Å absorption line absorbed flux
52- 56 F5.3 10-15W/m2 F5406 FeI 5406Å absorption line absorbed flux
58- 62 F5.3 10-15W/m2 F5430 FeI 5430Å absorption line absorbed flux
64- 68 F5.3 10-15W/m2 F5435 FeI 5435Å absorption line absorbed flux
70- 74 F5.3 10-15W/m2 F5501 FeI 5501Å absorption line absorbed flux
76- 80 F5.3 10-15W/m2 F5507 FeI 5507Å absorption line absorbed flux
82- 86 F5.3 10-15W/m2 F6412 FeI 6412Å absorption line absorbed flux
88- 92 F5.3 10-15W/m2 F6469 FeI 6469Å absorption line absorbed flux
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 02-Nov-2023