J/AJ/152/1 Spectroscopy of EG And over roughly 14 years (Kenyon+, 2016)
EG andromedae: a new orbit and additional evidence for a photoionized wind.
Kenyon S.J., Garcia M.R.
<Astron. J., 152, 1-1 (2016)>
=2016AJ....152....1K 2016AJ....152....1K (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: binaries: spectroscopic - binaries: symbiotic -
stars: individual (EG And) - stars: winds, outflows
Abstract:
We analyze a roughly 20yr set of spectroscopic observations for the
symbiotic binary EG And. Radial velocities derived from echelle
spectra are best fit with a circular orbit having an orbital period of
P=483.3±1.6 days and semi-amplitude K=7.34±0.07km/s. Combined with
previous data, these observations rule out an elliptical orbit at the
10σ level. Equivalent widths of HI Balmer emission lines and
various absorption features vary in phase with the orbital period.
Relative to the radius of the red giant primary, the apparent size of
the H ii region is consistent with a model where a hot secondary star
with effective temperature Th∼75000K ionizes the wind from the red
giant.
Description:
From 1994 September to 2016 January, P. Berlind, M. Calkins, and other
observers acquired 480 low-resolution optical spectra of EG And with
FAST, a high throughput, slit spectrograph mounted at the Fred L.
Whipple Observatory 1.5m telescope on Mount Hopkins, Arizona They used
a 300g/mm grating blazed at 4750Å, a 3'' slit, and a thinned
512*2688 CCD. These spectra cover 3800-7500Å at a resolution of
6Å. The full wavelength solution is derived from calibration lamps
acquired immediately after each exposure. The wavelength solution for
each frame has a probable error of ≲±0.5Å. Most of the resulting
spectra have moderate signal-to-noise ratio, S/N ≳15-30 per pixel.
Prior to the start of the FAST observations, we obtained occasional
optical spectrophotometric observations of EG And throughout 1982-1989
with the cooled dual-beam intensified Reticon scanner (IRS) mounted on
the white spectrograph at the KPNO No. 1 and No. 2 90cm telescopes.
Various remote observers acquired high-resolution spectroscopic
observations of EG And with the echelle spectrographs and Reticon
detectors on the 1.5m telescopes of the Fred L. Whipple Observatory on
Mount Hopkins, Arizona and the Oak Ridge Observatory in Harvard,
Massachusetts. These spectra cover a 44Å bandpass centered near
5190Å or 5200Å and have a resolution of roughly 12km/s.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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00 44 37.19 +40 40 45.7 EG And = HD 4174 (P=483.3)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 30 106 EG And radial velocity data
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See also:
B/sb : 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix+ 2004-2014)
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AN/333/242 : Recent photometry of symbiotic stars (Skopal+, 2012)
J/PASP/122/35 : Symbiotic stars on Asiago plates (Jurdana-Sepic+, 2010)
J/A+AS/146/407 : Symbiotic stars catalogue (Belczynski+, 2000)
J/A+A/318/53 : UBV photometry of EG And (Skopal 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d JD [45243.7/50438.6] Modified Julian Date (JD-2400000)
12- 16 F5.3 --- Phase [0/1] Orbital phase (1)
18- 24 F7.2 km/s RV [-103.18/-86.95] Radial velocity (vr)
26- 30 F5.2 km/s O-C [-2/1.61] The (O-C) residual
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Note (1): The orbital phase is the fractional part of:
Φ=(JD-T0)/P, where
* JD is the Julian Date listed above;
* T0=JD2450213.508;
* P=483.3days.
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 19-Aug-2016