scholarly journals Low-amplitude and long-period radial velocity variations in giants HD 3574, 63 Cygni, and HD 216946

2014 ◽  
Vol 566 ◽  
pp. A124
Author(s):  
B.-C. Lee ◽  
I. Han ◽  
M.-G. Park ◽  
A. P. Hatzes ◽  
K.-M. Kim
Keyword(s):  
Radial Velocity ◽  
Long Period ◽  
Velocity Variations ◽  
Low Amplitude

Radial Velocity Variations in Cool Supergiants

1984 ◽  
Vol 88 ◽  
pp. 283-288
Author(s):  
Hugh C. Harris
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Short Period ◽  
Cool Stars ◽  
Synchronous Rotation ◽  
Red Supergiants ◽  
Velocity Variations ◽  
Orbital Periods ◽  
Low Amplitude ◽  
Good Agreement

AbstractA survey of F, G, and W supergiants has been carried out with the DAO radial velocity spectrometer, an efficient instrument for detecting low-amplitude velocity variations in cool stars. Observations of 78 stars over five seasons show generally good agreement with OORAVEL results for spectroscopie binaries. The majority of supergiants show low-amplitude variability, with amplitudes typically 1 to 2 km s−1. The width of the cross-correlation profile has been measured for 58 supergiants. It reveals 14 stars with unusually broad lines, indicative of rotation velocities of 15 to 35 km s−1. Several have short-period binary companions and may be in synchronous rotation. The other broad-lined stars are apparently single or with long orbital periods; they may be making their first transition from the main sequence to become red supergiants.

scholarly journals Precise Radial Velocities

1992 ◽  
Vol 135 ◽  
pp. 67-72
Author(s):  
Gordon A.H. Walker
Keyword(s):  
Radial Velocity ◽  
Radial Velocities ◽  
Velocity Variations ◽  
Low Amplitude

AbstractCurrent techniques for the detection of long-term, low-amplitude (<50 m s−1), radial velocity variations are briefly reviewed together with some of their most successful programs. In the era of 8- to 10-m telescopes we must strive for a precision of < 1ms−1.

Long-period radial velocity variations in three K giants

1993 ◽  
Vol 413 ◽  
pp. 339 ◽  
Author(s):  
Artie P. Hatzes ◽  
William D. Cochran
Keyword(s):  
Radial Velocity ◽  
Long Period ◽  
Velocity Variations ◽  
K Giants

scholarly journals Radial-velocity Variations of Late-type Variables

1999 ◽  
Vol 170 ◽  
pp. 228-232
Author(s):  
Stephenson L.S. Yang ◽  
Gordon A.H. Walker ◽  
Ana M. Larson
Keyword(s):  
Radial Velocity ◽  
Hydrogen Fluoride ◽  
Absorption Cell ◽  
Late Type ◽  
Velocity Variations ◽  
Low Amplitude

AbstractLow-amplitude, radial-velocity variations of bright late-type stars were monitored at the 1.2-m telescope of the Dominion Astrophysical Observatory (DAO) with the hydrogen fluoride (HF) absorption-cell technique. Many of the stars appear to be semi-regular red variables (SRb and SRc) and irregular red variables (Lb). The radial-velocity amplitudes range from a few tens of meters per second to a few kilometers per second while the timescales of the variations appear to range from a few tens of days to a few hundreds of days. These irregular-looking velocities are analysed for multiperiodicities. There are also variations in the chromospheric Ca II 8662 index for a few of the variables.

scholarly journals Two new double-lined spectroscopic binary white dwarfs

2020 ◽  
Vol 493 (2) ◽  
pp. 2805-2816 ◽  
Author(s):  
Mukremin Kilic ◽  
A Bédard ◽  
P Bergeron ◽  
Alekzander Kosakowski
Keyword(s):  
Radial Velocity ◽  
White Dwarf ◽  
White Dwarfs ◽  
Binary Systems ◽  
Mass Ratio ◽  
Orbital Parameters ◽  
Long Period ◽  
Spectroscopic Binary ◽  
Velocity Variations ◽  
Period System

ABSTRACT We present radial velocity observations of four binary white dwarf candidates identified through their overluminosity. We identify two new double-lined spectroscopic binary systems, WD 0311–649 and WD 1606+422, and constrain their orbital parameters. WD 0311–649 is a 17.7 h period system with a mass ratio of 1.44 ± 0.06 and WD 1606+422 is a 20.1 h period system with a mass ratio of 1.33 ± 0.03. An additional object, WD 1447–190, is a 43 h period single-lined white dwarf binary, whereas WD 1418–088 does not show any significant velocity variations over time-scales ranging from minutes to decades. We present an overview of the 14 overluminous white dwarfs that were identified by Bédard et al., and find the fraction of double- and single-lined systems to be both 31 per cent. However, an additional 31 per cent of these overluminous white dwarfs do not show any significant radial velocity variations. We demonstrate that these must be in long-period binaries that may be resolved by Gaia astrometry. We also discuss the overabundance of single low-mass white dwarfs identified in the SPY survey, and suggest that some of those systems are also likely long-period binary systems of more massive white dwarfs.

Bright Giants with Small Amplitude Long Period Velocity Variability

1984 ◽  
Vol 88 ◽  
pp. 289-297
Author(s):  
Willet I. Beavers
Keyword(s):  
Radial Velocity ◽  
Small Amplitude ◽  
Variable Velocity ◽  
Complete Cycle ◽  
Giant Stars ◽  
Long Period ◽  
Velocity Variations

AbstractObservations during the first eight years of operation of the Fick Observatory photoelectric radial velocity spectrometer have led to the development of a list of approximately seventy bright late giant stars with suspected small amplitude long period velocity variations. Some of these stars have been identified as variable velocity objects by other observers, and a few of them have previous low quality orbit determinations or estimations. Preliminary SB1 orbits are reported for eight of the list members which have been observed through at least one complete cycle. Estimates of the period (P) and velocity semiamplitude (K) are made for other confirmed variables. Generally, the sample contains long P (2 to 8 years), small K (4 to 14 km/sec), late giant systems.

scholarly journals Velocity Observations of Multiple Mode AGB Variable Stars

2002 ◽  
Vol 185 ◽  
pp. 560-561
Author(s):  
T. Lebzelter ◽  
K.H. Hinkle ◽  
R.R. Joyce ◽  
F.C. Fekel
Keyword(s):  
Radial Velocity ◽  
Orbital Motion ◽  
Variable Stars ◽  
Spectroscopic Observations ◽  
Long Period ◽  
Multiple Mode ◽  
Infrared Spectroscopic ◽  
Velocity Variations ◽  
Velocity Changes ◽  
Light Variability

AbstractNumerous infrared Spectroscopic observations were obtained of eight AGB field M giants that have multiple periods of light variability. For six of the eight giants we found radial-velocity periods that confirm the long-period light variability. Although we consider the possibility that the velocity variations result from orbital motion, we conclude that the long-period velocity changes in most, if not all of our sample stars, likely result from pulsation rather than duplicity.

Search for Long-Period Radial Velocity Variations in Some Be Stars

Be Stars ◽  
1982 ◽  
pp. 155-159
Author(s):  
L. Pastori ◽  
E. Antonello ◽  
M. Fracassini ◽  
L. E. Pasinetti
Keyword(s):  
Radial Velocity ◽  
Be Stars ◽  
Long Period ◽  
Velocity Variations
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