J/MNRAS/387/1563 Radial velocity curves of AE Aqr (Echevarria+, 2008)
High-dispersion absorption-line spectroscopy of AE Aqr.
Echevarria J., Smith R.C., Costero R., Zharikov S., Michel R.
<Mon. Not. R. Astron. Soc., 387, 1563-1574 (2008)>
=2008MNRAS.387.1563E 2008MNRAS.387.1563E
ADC_Keywords: Binaries, cataclysmic ; Radial velocities
Keywords: binaries: close - stars: individual: AE Aqr -
novae, cataclysmic variables - stars: rotation
Abstract:
High-dispersion time-resolved spectroscopy of the unique magnetic
cataclysmic variable AE Aqr is presented. A radial velocity analysis
of the absorption lines yields K2=168.7±1km/s . Substantial
deviations of the radial velocity curve from a sinusoid are
interpreted in terms of intensity variations over the secondary star's
surface. A complex rotational velocity curve as a function of orbital
phase is detected which has a modulation frequency of twice the
orbital frequency, leading to an estimate of the binary inclination
angle that is close to 70°. The minimum and maximum rotational
velocities are used to indirectly derive a mass ratio of q=0.6 and a
radial velocity semi-amplitude of the white dwarf of K1=101±3km/s.
We present an atmospheric temperature indicator, based on the
absorption-line ratio of FeI and CrI lines, whose variation indicates
that the secondary star varies from K0 to K4 as a function of orbital
phase. The ephemeris of the system has been revised, using more than
1000 radial velocity measurements, published over nearly five decades.
From the derived radial velocity semi-amplitudes and the estimated
inclination angle, we calculate that the masses of the stars are
M1=0.63±0.05M☉; M2=0.37±0.04M☉ , and their separation
is a=2.33±0.02R_☉. Our analysis indicates the presence of a
late-type star whose radius is larger, by a factor of nearly 2, than
the radius of a normal main-sequence star of the same mass. Finally,
we discuss the possibility that the measured variations in the
rotational velocity, temperature and spectral type of the secondary
star as functions of orbital phase may, like the radial velocity
variations, be attributable to regions of enhanced absorption on the
star's surface.
Description:
Spectroscopic observations of AE Aqr were made using the AAT and the
University College London Echelle Spectrograph (UCLES) at the coude
focus on 1991 August 2 and 3.
Three further runs were obtained at the Observatorio Astronomico
Nacional at San Pedro Martir (SPM) using the 2.1-m telescope and the
Echelle Spectrograph. The first observations were gathered on the
nights of 1997 September 22 and 23.
The second set of observations were made on the nights of 2000 August
17 to 19.
The third run was made on 2001 August 29.
Objects:
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RA (2000) DE Designation(s)
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20 40 09.2 -00 52 15 AE Aqr = V* AE Aqr
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables.dat 29 247 Radial velocities for AE Aqr for 1991/08/2,
1991/08/3, 1997/09/22-23, 2000/08/17-18,
2000/08/19 and 2001/08/29
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Byte-by-byte Description of file: tables.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian date
14- 22 F9.4 km/s RV Radial velocity
24- 29 F6.3 km/s e_RV rms uncertainty on RV
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Nov-2008