High-resolutionH-band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability

2017 ◽  
Vol 153 (4) ◽  
pp. 174 ◽  
Author(s):  
S. Drew Chojnowski ◽  
John P. Wisniewski ◽  
David G. Whelan ◽  
Jonathan Labadie-Bartz ◽  
Marcelo Borges Fernandes ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Be Stars

scholarly journals Short-period Variations of 28 CMa during 1998/9

2000 ◽  
Vol 175 ◽  
pp. 236-239
Author(s):  
L.A. Balona ◽  
D. James
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Periodic Variation ◽  
Emission Lines ◽  
Circumstellar Disk ◽  
Be Stars ◽  
Short Period ◽  
Metal Absorption ◽  
Period Variations ◽  
Be Star

AbstractThe Be star 28 CMa was one of the first periodic Be stars to be discovered and shows very large line profile variations with a period of 1.37 d. Recently, it has been shown that the line profile and light variations can be modeled by a patch of gas suspended above the photosphere. We present echelle observations of the Hβ and Hϒ line and several helium and metal absorption lines. We show that the radial velocity variations of these lines are unchanged since they were first observed two decades ago. We also examined several emission lines of Fe II and show that they do not partake of the periodic variation. We attribute the periodic variations of the lines formed close to the photosphere to a co-rotating cloud, whereas the Fe II emission lines are formed in the circumstellar disk outside the co-rotating radius.

scholarly journals An Extraordinary Early-Type Eclipsing Binary

1993 ◽  
Vol 139 ◽  
pp. 188-188
Author(s):  
L.A. Balona ◽  
J. Cuypers
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Stellar Dynamics ◽  
Comparison Star ◽  
Be Stars ◽  
Early Type ◽  
Test Bed ◽  
Eclipsing Binary ◽  
Photometric Observations ◽  
Unique System

HR 2680 (B5V) was used as a comparison star in a multi-site (ESO & SAAO) campaign organised in 1988 to observe Be stars. We found that the star is an eclipsing binary with a period of 8.1 days. The eclipse is partial with a depth of 0.18 mag. Radial velocity observations confirmed the period.A light variation with an amplitude of as much as 0.03 mag was seen outside the eclipse (Fig. 1). This variation can be interpreted as two oscillations with approximate periods of 1.19 and 1.28 days. Further photometric observations were obtained in 1989, 1990 and 1991 at SAAO. The multiperiodicity was confirmed, but the periods were not constant from season to season.We suspect that the star is a pulsator of the 53 Per class of line-profile variables. Being an eclipsing binary, this unique system is of potentially great importance as a test bed for stellar dynamics and nonradial pulsations.

scholarly journals Comparison of Selected Methods for Radial Velocity Measurements

2006 ◽  
Vol 2 (S240) ◽  
pp. 486-489
Author(s):  
Štefan Parimucha ◽  
Petr Škoda
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Cross Correlation ◽  
Radial Velocities ◽  
Be Stars ◽  
Velocity Measurements ◽  
Stellar Spectra ◽  
Advantages And Disadvantages ◽  
Profile Fitting ◽  
Correlation Line

AbstractWe present a comparison of selected methods for measuring radial velocities in stellar spectra. We compare cross-correlation, line-profile fitting with Gauss, Lorentz and Voigt functions and a less-known mirroring method. We discuss their applicability and precision and indicate their advantages and disadvantages. The mirroring method proved to be useful for the analysis of Be stars, but is not implemented in any major astronomical packages.

scholarly journals The FeII λ5317 line profile of nine Be stars

1994 ◽  
Vol 162 ◽  
pp. 263-264
Author(s):  
D. Ballereau ◽  
J. Chauville ◽  
J. Zorec
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Be Stars

Our aim is to analyze the FeII λ5317 emission line of nine Be stars recorded in 1990, to deduce some constraints on the modeling of their envelope and to compare them to the results obtained in 1985 and 1987 by other authors.

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 Fiber Fed Spectrograph for Line Variability Studies

1988 ◽  
Vol 132 ◽  
pp. 31-34 ◽  
Author(s):  
P. Felenbok ◽  
J. Guérin
Keyword(s):  
Line Profile ◽  
Main Sequence ◽  
Single Site ◽  
Be Stars ◽  
Correlated Observations ◽  
Rotational Modulation ◽  
High Flexibility ◽  
Gain Access ◽  
Star Rotation

In our studies of activity in pre-main sequence Herbig Ae/Be stars we are mainly interested in searching rotational modulation of line profile. If the period of star rotation is of the order of one or two days, the data collected from a single site is insufficient. This led us to start correlated observations from two or three sites spread as much as possible in longitude. Our first bi-site observations started in 1982 on AB Aur from two observatories located 11 hours apart.: CFHT in Hawaï and OHP in France. To achieve a high flexibility and to gain access to telescopes without attached spectrographs. We built an instrument that is mobile and specially designed for line profile studies.

scholarly journals Simultaneous Spectroscopy and Polarimetry of Be Stars

1987 ◽  
Vol 92 ◽  
pp. 84-86
Author(s):  
D. R. Gies ◽  
David McDavid
Keyword(s):  
Mass Loss ◽  
Emission Line ◽  
Absorption Line ◽  
Line Profile ◽  
Circumstellar Envelope ◽  
Be Stars ◽  
Line Profiles ◽  
Initial Attempt ◽  
Rapid Variability ◽  
Hα Emission

Evidence is now accumulating that many Be stars display photospheric line profile variations on timescales of days or less that are probably caused by nonradial pulsations (Baade 1984; Penrod 1986). In some circumstances these pulsations can promote mass loss into the circumstellar envelope, and consequently the conditions in the inner part of the envelope may vary on similar timescales. Changes in the envelope could produce variations in the polarization and emission line profiles, and observers have reported rapid variability in both. We describe here an initial attempt to search for simultaneous variations in continuum polarization, Hα emission, and the He I λ6678 photospheric absorption line in order to investigate correlated changes on short timescales.

Long-term radial velocity variations in some Be stars

1982 ◽  
Vol 83 (1-2) ◽  
pp. 381-390 ◽  
Author(s):  
Elio Antonello ◽  
Massimo Fracassini ◽  
Laura Enrica Pasinetti ◽  
Livio Pastori
Keyword(s):  
Radial Velocity ◽  
Be Stars ◽  
Velocity Variations

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.

scholarly journals The Texas High-Precision Radial-velocity Programs

1999 ◽  
Vol 170 ◽  
pp. 113-120
Author(s):  
William D. Cochran ◽  
Artie P. Hatzes
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
High Precision ◽  
Line Profile ◽  
Planetary Systems ◽  
Profile Measurement ◽  
European Southern Observatory ◽  
University Of Texas ◽  
The University ◽  
Search Program

AbstractSeveral different high-precision radial-velocity programs are now underway at The University of Texas. This paper discusses the aspects of these programs that are related to the problem of detection of extrasolar planetary systems. This includes the McDonald Observatory Planetary Search program on the McDonald 2.7-m Harlan Smith Telescope, an accompanying program of high-resolution stellar line profile measurement, the European Southern Observatory planetary search program, the Keck Hyades survey, and the Hobby∙Eberly Telescope planet surveys. Here, we summarize each of these programs, and present recent results from each.

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