scholarly journals Spectral variation of BU Tau

2010 ◽  
Vol 6 (S272) ◽  
pp. 380-381
Author(s):  
Kalju Annuk
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Line Intensity ◽  
Equivalent Width ◽  
Spectral Variation ◽  
Spectroscopic Observations

AbstractWe present the preliminary result of our spectroscopic observations covering a period over more than ten years, from 1999 up to 2010. We analyze line profile variations of several lines before the shell phase and during the shell phase. The measured radial velocity, equivalent width and line intensity variations are presented.

scholarly journals Pulsations in 66 Oph: Multiperiodicity in He I 6678

2000 ◽  
Vol 175 ◽  
pp. 256-259 ◽  
Author(s):  
M. Floquet ◽  
C. Neiner ◽  
D. Briot ◽  
J. Chauville ◽  
A.M. Hubert ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Equivalent Width ◽  
Phase Distribution ◽  
Line Profiles ◽  
Short Term ◽  
Spectroscopic Observations

Abstract66 Oph has shown recurrent short-lived outbursts nicely detected from ground-based and space (Hipparcos) photometry.Spectroscopic observations of He I 6678 and Hα lines were performed in June 1997 and June 1998. Search for short-term periodicities was done in He I 6678 line profiles as in equivalent width EW, radial velocity of the line centroid, and V and R components. At least two frequencies were present: ν = 4.0 c/d and ν = 2.2 c/d. The phase distribution of these frequencies over the line profile corresponds in the nrp frame to g-modes with ℓ ~ 3 − 4 and ℓ = 2 respectively.

Spectroscopic Observations of Visual Double Stars

1965 ◽  
Vol 5 ◽  
pp. 109-111
Author(s):  
Frederick R. West
Keyword(s):  
Radial Velocity ◽  
High Dispersion ◽  
Velocity Difference ◽  
Spectrograph Slit ◽  
Spectroscopic Observations ◽  
Double Stars ◽  
Visual Double Stars ◽  
Relative Orbit ◽  
Two Component ◽  
Star Images

There are certain visual double stars which, when close to a node of their relative orbit, should have enough radial velocity difference (10-20 km/s) that the spectra of the two component stars will appear resolved on high-dispersion spectrograms (5 Å/mm or less) obtainable by use of modern coudé and solar spectrographs on bright stars. Both star images are then recorded simultaneously on the spectrograph slit, so that two stellar components will appear on each spectrogram.

scholarly journals Magnetism of the He-weak star HR 2949

2010 ◽  
Vol 6 (S272) ◽  
pp. 210-211
Author(s):  
Thomas Rivinius ◽  
Gregg A. Wade ◽  
Richard H. D. Townsend ◽  
Matthew Shultz ◽  
Jason H. Grunhut ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Line Profile ◽  
Equivalent Width ◽  
Rotational Line ◽  
Phase Lag ◽  
Abundance Patterns ◽  
Weak Star ◽  
Hydrogen Lines

AbstractA magnetic field and rotational line profile variability (lpv) is found in the He-weak star HR 2949. The field measured from metallic lines varies in a clearly non-sinusoidal way, and shows a phase lag relative to the morphologically similar He i equivalent width variations. The surface abundance patterns are strong and complex, and visible even in the hydrogen lines.

scholarly journals Radial Velocity of the Central Star of NGC 1514

1968 ◽  
Vol 34 ◽  
pp. 329-329
Author(s):  
A. Mammano ◽  
R. Margoni ◽  
M. Perinotto
Keyword(s):  
Radial Velocity ◽  
Planetary Nebula ◽  
Central Star ◽  
Spectroscopic Observations ◽  
Binary Hypothesis

We would like to report on some spectroscopic observations made of the central star of the planetary nebula NGC 1514, which we think can support the binary hypothesis now advanced by Kohoutek.

scholarly journals Wolf-Rayet binaries: old friends and new acquaintances

1999 ◽  
Vol 193 ◽  
pp. 26-37 ◽  
Author(s):  
Virpi S. Niemela ◽  
Roberto Gamen ◽  
Nidia I. Morrell ◽  
Sixto Giménez Benítez
Keyword(s):  
Radial Velocity ◽  
Binary Systems ◽  
Magellanic Cloud ◽  
Elliptic Orbit ◽  
Spectral Lines ◽  
Small Magellanic Cloud ◽  
Orbital Elements ◽  
Spectroscopic Observations ◽  
Short Period ◽  
Old Friends

Observations of WR stars in binary systems are discussed, emphasizing constraints on our knowledge of the binary frequency of WR stars, and of WR stars as a distinctive class of objects. Radial velocity orbits of newly discovered binaries, e.g., WR 29, a short period WN7+OB binary in our Galaxy, and SMC/AB 7, a massive WN+O7 binary in the Small Magellanic Cloud, are presented. New spectroscopic observations of binary systems with previously known orbits are also reported, showing in the case of WR 21 evidence of change of the orbital elements as derived from different spectral lines. An elliptic orbit for CV Ser is also illustrated.

scholarly journals The Reconciliation of Visual and Spectroscopic Observations of Binary Systems

1983 ◽  
Vol 62 ◽  
pp. 271-285 ◽  
Author(s):  
Alan H. Batten
Keyword(s):  
Radial Velocity ◽  
Binary Systems ◽  
Velocity Variation ◽  
Small Range ◽  
Orbital Elements ◽  
Spectroscopic Observations ◽  
Mutual Independence ◽  
Visual Binaries

AbstractThe special problems presented to the computer of orbits by radial-velocity observations of visual binaries are discussed under three heads: (i) problems caused by the small range of velocity variation, (ii) problems caused by the long periods, (iii) inconsistency between visual and spectroscopic observations. It is pointed out that radial-velocity observations, even when they are insufficient for independent determinations of orbital elements, impose constraints on possible values of those elements which may in fact be helpful to the computer of visual orbits. In particular, as is illustrated by reference to ADS 8189, even a few observations of the radial-velocity are sufficient to destroy the mutual independence of the elements e, and ω.

Radial Velocity and Line Profile Variations in the Dwarf Nova Em-Cygni

1981 ◽  
Vol 248 ◽  
pp. 696 ◽  
Author(s):  
R. J. Stover ◽  
E. L. Robinson ◽  
R. E. Nather
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Dwarf Nova

scholarly journals Photometric and Spectroscopy Observations of Peculiar Nuclei of Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 309-309
Author(s):  
G. Jasniewicz ◽  
A. Acker
Keyword(s):  
Radial Velocity ◽  
Planetary Nebulae ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations ◽  
Ccd Detector ◽  
Central Stars

Photometric and spectroscopic observations of some bright central stars of planetary nebulae (PN) have been conducted between 1984 and 1987 with the following tools: differential photometer P7 (70-cm swiss telescope, La Silla c/o ESO); radial velocity scanner CORAVEL (1-m swiss telescope, Observatoire de Haute-Provence = OHP); spectrograph CARELEC with CCD detector (193-cm telescope, OHP).

scholarly journals Star-planet interaction through spectral lines

2019 ◽  
Vol 15 (S354) ◽  
pp. 280-285
Author(s):  
C. Villarreal D’Angelo ◽  
A. A. Vidotto ◽  
A. Esquivel ◽  
M. A. Sgró ◽  
T. Koskinen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Line Profile ◽  
Theoretical Models ◽  
Spectral Lines ◽  
3D Simulations ◽  
Spectroscopic Observations ◽  
Exoplanetary Systems ◽  
Exoplanetary Atmospheres

AbstractThe growth of spectroscopic observations of exoplanetary systems allows the possibility of testing theoretical models and studying the interaction that exoplanetary atmospheres have with the wind and the energetic photons from the star. In this work, we present a set of numerical 3D simulations of HD 209458b for which spectral lines observations of their evaporative atmosphere are available. The different simulations aim to reproduce different scenarios for the star-planet interaction. With our models, we reconstruct the Lyα line during transit and compare with observations. The results allows us to analyse the shape of the line profile under these different scenarios and the comparison with the observations suggest that HD209458b may have a magnetic field off less than 1 G. We also explore the behaviour of the magnesium lines for models with and without magnetic fields.

scholarly journals Observations of Highly-Ionized Interstellar Iron

1984 ◽  
Vol 81 ◽  
pp. 189-191
Author(s):  
L.M. Hobbs
Keyword(s):  
Radial Velocity ◽  
Absorption Line ◽  
Equivalent Width ◽  
Column Density ◽  
Light Path ◽  
Interstellar Gas ◽  
X Ray ◽  
X Ray Background ◽  
Multi Phase ◽  
No Absorption

AbstractThe spectra of 24 stars, including 5 at distances d < 200 pc, have been observed in the regions of the coronal [Fe X] λ6375 and [Fe XIV] λ5303 lines at detection limits near an equivalent width of 1 mÅ in the best cases. In general agreement with predictions based on a multi-phase model of the interstellar medium, no absorption which can be attributed to Fe X or Fe XIV ions in hot interstellar gas emitting the soft x-ray background is seen in any of these spectra, except for two. Toward λ Cephei an absorption line near λ6375 is measured with an equivalent width of 8.1 ± 2 mÅ, a width corresponding to 20 ± 5 km s-1 or a temperature T ≤ (0.5 ± 0.25) x 106 °K, and, if it is caused by Fe X ions, a radial velocity of -355 km s-1. On that hypothesis, the hot interstellar gas constitutes at least 63% of the column density of gas along this light path.

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