scholarly journals Discrepant Measurements of the Radial Velocities of SS Cygni: Solution to the Problem

1987 ◽  
Vol 93 ◽  
pp. 113-118
Author(s):  
E.L. Robinson
Keyword(s):  
Radial Velocity ◽  
Accretion Disk ◽  
White Dwarf ◽  
Center Of Mass ◽  
Velocity Curve ◽  
Radial Velocities ◽  
Radial Velocity Curve ◽  
Dwarf Nova

AbstractWe show that the discrepancies among the various measurements of the radial velocity curve of the K5 V star in the dwarf nova SS Cyg have been caused by (1) poor choices of lines for measuring its velocity and (2) large distortions in its velocity caused by heating from the white dwarf and its accretion disk. The correct K velocity of the center of mass of the K5 V star is 158 ± 3 km s−1.

scholarly journals New Spectroscopic Observations of Dwarf Nova BZ Ursae Majoris with Extremely Unusual Emission Lines Profiles

2004 ◽  
Vol 194 ◽  
pp. 269-269 ◽  
Author(s):  
V. V. Neustroev ◽  
S. V. Zharikov ◽  
A. Medvedev ◽  
A. Shearer
Keyword(s):  
Radial Velocity ◽  
Emission Line ◽  
Velocity Curve ◽  
Emission Lines ◽  
Radial Velocity Curve ◽  
Dwarf Nova ◽  
Preliminary Results ◽  
Spectroscopic Observations ◽  
Medium Resolution ◽  
Hα Emission

We present preliminary results of new spectroscopic observations of dwarf nova BZ UMa in quiescence. Fifty medium resolution spectra allow us to reproduce the radial velocity curve from the Hα emission line. We confirm that BZ UMa shows extremely unusual emission lines profiles, Unlike the classical single or the double-peaked profiles usually observed in spectra of dwarf novae, emission lines of BZ UMa consist of at least five peaks.

scholarly journals Red Spectroscopy of IP Pegasi

1987 ◽  
Vol 93 ◽  
pp. 145-149
Author(s):  
J.S. Martin ◽  
D.H.P. Jones ◽  
R.C Smith
Keyword(s):  
Radial Velocity ◽  
Cross Correlation ◽  
Main Sequence ◽  
Mass Function ◽  
Velocity Curve ◽  
Absorption Lines ◽  
Radial Velocity Curve ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Dwarf Nova

AbstractTime resolved spectroscopy of the dwarf nova IP Pegasi in the range λλ 7670–8320Å shows absorption lines originating from the cool secondary. A radial velocity curve for this component has been derived by cross-correlation with a normal M star. The curve has semi-amplitude K2 = 288.3 ± 4 km s−1, and is slightly distorted. This distortion is equivalent to an orbit with an apparent eccentricity of 0.075 ± 0.024. The mass function of the primary is 0.394 ± 0.016M⊙. From this we derive constraints on the component masses of 0.62 < M1 < 1.14M⊙ and 0.17 < M2 < 0.71M⊙. The red star has a radius in the range 0.32 < R2 < 0.51R⊙ and is probably on the main sequence.

scholarly journals Asymmetry of metallic spectral lines in Cepheids

1993 ◽  
Vol 139 ◽  
pp. 375-375
Author(s):  
Michael Albrow ◽  
P.L. Cottrel
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Velocity Curve ◽  
Radial Velocities ◽  
Spectral Lines ◽  
Line Profiles ◽  
Radial Velocity Curve ◽  
Spectroscopic Observations ◽  
The Asymmetry

AbstractA program of high resolution spectroscopic observations of Cepheids has been carried out at Mt John University Observatory for several years. Radial velocities and asymmetries have been measured for selected metallic lines using the method of Wallerstein et al (1992).The line profiles show the largest asymmetry at phases of maximum inward velocity. The asymmetry at phases of maximum outward velocity is smaller and sometimes in the same direction as for the inward velocity maxima. Enhanced asymmetry is also noticed at phases where the bump appears on the radial velocity curve.To date our models are unable to predict such behaviour. It is important that a satisfactory explaination for these observations be found so that the accuracy of Baade-Wesselink radius solutions for such stars can be assessed.

scholarly journals Superoutbursts and Superhumps of SU UMa Stars

1988 ◽  
Vol 108 ◽  
pp. 238-239
Author(s):  
Yoji Osaki ◽  
Masahito Hirose
Keyword(s):  
Accretion Disk ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Systems ◽  
Roche Lobe ◽  
Light Curves ◽  
Close Binary ◽  
Dwarf Novae ◽  
Dwarf Nova ◽  
Close Binary Systems

SU UMa stars are one of subclasses of dwarf novae. Dwarf novae are semi-detached close binary systems in which a Roche-lobe filling red dwarf secondary loses matter and the white dwarf primary accretes it through the accretion disk. The main characteristics of SU UMa subclass is that they show two kinds of outbursts: normal outbursts and superoutbursts. In addition to the more frequent narrow outbursts of normal dwarf nova, SU UMa stars exhibit “superoutbursts”, in which stars reach about 1 magnitude brighter and stay longer than in normal outburst. Careful photometric studies during superoutburst have almost always revealed the “superhumps”: periodic humps in light curves with a period very close to the orbital period of the system. However, the most curious of all is that this superhump period is not exactly equal to the orbital period, but it is always longer by a few percent than the orbital period.

scholarly journals The Radial Velocity Curve of V652 Her (BD+13°3224)

1985 ◽  
Vol 87 ◽  
pp. 109-115
Author(s):  
P.W. Hill ◽  
C.S. Jeffery
Keyword(s):  
Radial Velocity ◽  
Time Resolution ◽  
High Frequency ◽  
Velocity Curve ◽  
Velocity Data ◽  
Effective Surface ◽  
Radial Velocity Curve ◽  
Minimum Radius ◽  
Helium Star ◽  
Radial Velocity Data

AbstractNew radial velocity data for the pulsating extreme helium star V652 Her (BD+13°3224) have been obtained with a time resolution of 100 s. High frequency structure in the radial velocity curve is detected, and a comparison with previous data suggests that the detailed shape of the velocity curve is variable. The data imply that the effective surface gravity must increase by a factor of 4 at minimum radius.

The radial-velocity curve of V1010 Ophiuchi - Orbital elements and the rotational disturbance

1988 ◽  
Vol 100 ◽  
pp. 371 ◽  
Author(s):  
Thaddeus F. Worek ◽  
Eugene R. Zizka ◽  
Merle W. King ◽  
Joost H. Kiewiet de Jonge
Keyword(s):  
Radial Velocity ◽  
Velocity Curve ◽  
Orbital Elements ◽  
Radial Velocity Curve

scholarly journals A new radial velocity curve for the RS CVn star σ Gem

1997 ◽  
Vol 123 (2) ◽  
pp. 209-218 ◽  
Author(s):  
R. Duemmler ◽  
I. V. Ilyin ◽  
I. Tuominen
Keyword(s):  
Radial Velocity ◽  
Velocity Curve ◽  
Radial Velocity Curve

A Radial-Velocity Curve for WR 46 (WN3p)

1995 ◽  
pp. 243-244 ◽  
Author(s):  
P. M. Veen ◽  
A. M. Van Genderen ◽  
M. A. W. Verhelfen ◽  
K. A. Van Der Hucht
Keyword(s):  
Radial Velocity ◽  
Velocity Curve ◽  
Radial Velocity Curve
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