scholarly journals The Observations of AG PEG During 1985–87

1988 ◽  
Vol 103 ◽  
pp. 257-257
Author(s):  
A.A. Boyarchuk ◽  
T.S. Belyakina ◽  
A.E. Tarasov ◽  
N. Tomov
Keyword(s):  
Radial Velocity ◽  
Absorption Line ◽  
Radial Velocities ◽  
Light Curves ◽  
Emission Lines

AbstractThe light curves in UBVRI and profiles of the emission lines of Hα, HeII 5411 and HeI 5876, 6678 obtained during 1985–87. The radial velocities of the emission lines HeI 6678 and HeII 5411 demonstrated clear periodic variations in antiphase with the radial velocity defined for the absorption line.

scholarly journals Recent studies of the spectrum of V1016 Cygni

1982 ◽  
Vol 70 ◽  
pp. 161-164
Author(s):  
G. Muratorio ◽  
M. Friedjung
Keyword(s):  
Radial Velocity ◽  
Ionization Potential ◽  
Radial Velocities ◽  
Emission Lines ◽  
Computer Programme ◽  
Half Maximum ◽  
The Mean ◽  
Effective Ionization

Two coudé spectra of V1016 Cyg taken on June 24 and 27, 1979 were reduced, using a computer programme developed in Marseille. Radial velocities and full widths at half maximum were measured for the emission lines, and are summarized in the following table were VR is the mean radial velocity in km s-1, DV the velocity corresponding to the mean FWHM and Xi the effective ionization potential for the ion.

scholarly journals Photometric and Radial Velocity Variations of R CrB Near Maximum Light

1985 ◽  
Vol 87 ◽  
pp. 191-197
Author(s):  
A.V. Raveendran ◽  
B.N. Ashoka ◽  
N. Kameswara Rao
Keyword(s):  
Fourier Analysis ◽  
Radial Velocity ◽  
Radial Velocities ◽  
Light Curves ◽  
Circumstellar Dust ◽  
Maximum Light ◽  
V Band ◽  
L Band ◽  
Velocity Variations ◽  
Visual Light

Abstract:Fourier analysis of the light curves of RCrB in V band near maximum shows that in addition to several significant short periods there is a modulation of the visual light with a period around 1170 day, similar to that of L band flux, noticed by strecker. This indicates that there is some contribution to the visual light variations of the star from the pulsating circumstellar dust. Radial velocities of R CrB obtained at Kavalur during February-May 1985 show variations with a period around 47 days.

scholarly journals High Luminosity F-K Stars Motions and Hα Emissions

1980 ◽  
Vol 51 ◽  
pp. 170-170
Author(s):  
J. Smolinski ◽  
J.L. Climenhaga ◽  
B.L. Harris
Keyword(s):  
Radial Velocity ◽  
Radial Velocities ◽  
Emission Lines ◽  
High Dispersion ◽  
Common Phenomenon ◽  
Line Profiles ◽  
High Luminosity ◽  
Regular Time ◽  
Time Variations

AbstractChanges and differences in radial velocities between neutral and ionized metals have been found for three F5-type supergiants: HD 231195, HD 10494, and HD 17971. Fifteen high dispersion coudé spectrograms (6 Å/mm) were used and 33 to 165 lines were measured on each. Semi-regular time variations up to about 8 km s-1 in radial velocity have been found. In addition, Hα line profiles for 8 high luminosity F-K stars have been analyzed. All of the stars show Ha emissions, variable in time, which is probably a common phenomenon in very luminous stars. Metallic emission lines with low excitation potentials, in particular the Ca I 6572.8 and the Fe I 6574.2 lines, are present in 5 of these stars.

scholarly journals Cepheid Radial Velocities and Phase Lag

2000 ◽  
Vol 176 ◽  
pp. 240-241
Author(s):  
M. E. Sachkov
Keyword(s):  
Radial Velocity ◽  
Preliminary Analysis ◽  
Radial Velocities ◽  
Light Curves ◽  
Phase Lag ◽  
Correlation Spectrometer

AbstractOur systematic measurements (since 1987) of radial velocities of northern Cepheids with a correlation spectrometer allowed us to make a detailed study of shapes of VR curves. This is a preliminary analysis of the phase lag between Cepheid radial velocity and light curves.

scholarly journals The Radial Velocities of Planetary Nebulae in NGC 3379

1993 ◽  
Vol 155 ◽  
pp. 570-570
Author(s):  
Robin Ciardullo ◽  
George Jacoby
Keyword(s):  
Radial Velocity ◽  
Absorption Line ◽  
Planetary Nebula ◽  
Velocity Dispersion ◽  
Planetary Nebulae ◽  
Elliptical Galaxies ◽  
Emission Lines ◽  
Surface Photometry ◽  
Stellar Kinematics ◽  
Velocity Measurements

Several authors have analyzed the kinematics of elliptical galaxies using surface photometry in combination with absorption line velocity dispersion measurements. However, these analyses never explore the halos of galaxies, since the best absorption line measurements extend only ∼1 re. The only way to extend our knowledge of stellar kinematics to larger radii is to use the emission lines of planetary nebula for radial velocity measurements.

scholarly journals Radial Velocities of SS Cygni

1979 ◽  
Vol 53 ◽  
pp. 489-493
Author(s):  
R. J. Stover
Keyword(s):  
Radial Velocity ◽  
Emission Line ◽  
Absorption Line ◽  
Orbital Period ◽  
Radial Velocities ◽  
Orbital Elements ◽  
Velocity Measurements ◽  
Light Spectrum ◽  
Minimum Light ◽  
Spectroscopic Binary

SS Cygni was found by Joy (1956) to be a spectroscopic binary with an orbital period of about 6-1/2 hours. At minimum light it has mv=12 and is the brightest member of the dwarf nova class of variables. The minimum light spectrum reveals faint, narrow absorption lines of a G- or K-type star along with strong, broad emission lines of hydrogen, helium, and calcium which are produced by an accretion disk surrounding a white dwarf star. Joy’s radial velocities were not very accurate. Nevertheless, he was able to estimate the orbital elements, finding 115 km/s for the absorption line K-velocity and 122 km/s for the emission line K-velocity. In addition, he derived an orbital period of 0276244. Later minimum light observations by Walker and Chincarini (1968) were too few to be able to improve the orbital elements. Kiplinger (1979) refined the emission line radial velocities but was not able to remeasure the faint absorption line spectrum. This paper presents new radial velocity measurements of both the emission and absorption line spectra of SS Cygni at minimum light, and is the first thorough investigation of this star’s radial velocity variations in more than 20 years. The accuracy of the radial velocity curves has been greatly improved. We also find that Joy’s orbital period is in error by nearly two minutes.

scholarly journals Gaia-assisted discovery of a detached low-ionisation BAL quasar with very large ejection velocities

2020 ◽  
Vol 634 ◽  
pp. A111 ◽  
Author(s):  
J. P. U. Fynbo ◽  
P. Møller ◽  
K. E. Heintz ◽  
J. N. Burchett ◽  
L. Christensen ◽  
...  
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Emission Lines ◽  
Broad Absorption ◽  
Broad Absorption Line ◽  
Red Edge ◽  
First Case ◽  
Bl Lac ◽  
Spatially Extended ◽  
Extended Emission

We report on the discovery of a peculiar broad absorption line (BAL) quasar identified in our Gaia-assisted survey of red quasars. The systemic redshift of this quasar was difficult to establish because of the absence of conspicuous emission lines. Based on deep and broad BAL troughs of at least Si IV, C IV, and Al III, a redshift of z = 2.41 was established under the assumption that the systemic redshift can be inferred from the red edge of the BAL troughs. However, we observe a weak and spatially extended emission line at 4450 Å that is most likely due to Lyman-α emission, which implies a systemic redshift of z = 2.66 if correctly identified. There is also evidence for the onset of Lyman-α forest absorption bluewards of 4450 Å and evidence for Hα emission in the K band consistent with a systemic redshift of z = 2.66. If this redshift is correct, the quasar is an extreme example of a detached low-ionisation BAL quasar. The BALs must originate from material moving with very large velocities ranging from 22 000 km s−1 to 40 000 km s−1. To our knowledge, this is the first case of a systemic-redshift measurement based on extended Lyman-α emission for a BAL quasar. This method could also be useful in cases of sufficiently distant BL Lac quasars without systemic-redshift information.

scholarly journals Astrometric Radial Velocities From Hipparcos

1998 ◽  
Vol 11 (1) ◽  
pp. 564-564
Author(s):  
D. Dravins ◽  
L. Lindegren ◽  
S. Madsen ◽  
J. Holmberg
Keyword(s):  
Radial Velocity ◽  
High Precision ◽  
Radial Velocities ◽  
Radial Motion ◽  
Spectral Lines ◽  
Parallel Program ◽  
Stellar Surface ◽  
Space Astrometry ◽  
Stellar Motion ◽  
Surface Convection

Abstract Space astrometry now permits accurate determinations of stellar radial motion, without using spectroscopy. Although the feasibility of deducing astrometric radial velocities from geometric projection effects was realized already by Schlesinger (1917), only with Hipparcos has it become practical. Such a program has now been carried out for the moving clusters of Ursa Major, Hyades, and Coma Berenices. Realized inaccuracies reach about 300 m/s (Dravins et al. 1997). Discrepancies between astrometric and spectroscopic radial velocities reveal effects (other than stellar motion) that affect wavelength positions of spectral lines. Such are caused by stellar surface convection, and by gravitational redshifts. A parallel program (Gullberg & Dravins 1997) is analyzing high-precision spectroscopic radial velocities for different spectral lines in these stars, using the ELODIE radial-velocity instrument atHaute-Provence.

The CORAVEL Radial Velocity Data Base

2017 ◽  
Vol 13 (S334) ◽  
pp. 271-272
Author(s):  
Stéphane Udry ◽  
Maxime Marmier ◽  
Michel Mayor ◽  
Johannes Andersen ◽  
Birgitta Nordström
Keyword(s):  
Radial Velocity ◽  
Data Base ◽  
Radial Velocities ◽  
Velocity Data ◽  
Radial Velocity Data

AbstractFrom 1977 to 1999, thousands of accurate radial velocities in both hemispheres were made on a large variety of programmes with the two CORAVEL scanners. The data base of ~350000 individual observations will now be made available to complement the Gaia data.

scholarly journals Ultraviolet Variability of the Symbiotic Star AG PEG

1988 ◽  
Vol 103 ◽  
pp. 263-264
Author(s):  
D. Chochol ◽  
Z. Komárek ◽  
A. Vittone
Keyword(s):  
Optical Spectra ◽  
Radial Velocities ◽  
Roche Lobe ◽  
Emission Lines ◽  
High Dispersion ◽  
Symbiotic Star ◽  
Observational Material

Symbiotic star AG Peg consists of a hot subdwarf with a WN6 spectrum and a cool M3 giant, which is not filling its Roche lobe (Boyarchuk 1967, 1985). A detailed study of profiles, equivalent widths and radial velocities of emission lines in optical spectra allowed Hutchings et al. (1975) to conclude that a hot subluminous star approximately 1 M⊙ rotates rapidly and ejects material which streams towards the cool M giant with the mass 3-4 M⊙. UV observations seems to support this model.UV observations provided from the databank of the IUE satellite were obtained in 1978–81 by different observers. The observational material consists of 12 high dispersion SWP spectra and covers the region 1200 – 2100 A. The spectra were reduced at Trieste observatory using standard IUESIPS package. The radial velocities of emission lines were measured on tracings and corrected for the motion of Earth and satellite.

Sign in / Sign up

Export Citation Format

Share Document