Velocity Observations of Multiple Mode AGB Variable Stars

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.

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Time-Lapse Monitoring of Daily Velocity Changes in Binchuan, Southwestern China, Using Large-Volume Air-Gun Source Array Data

Seismological Research Letters ◽

10.1785/0220210160 ◽

2022 ◽

Author(s):

Yi Luan ◽

Hongfeng Yang ◽

Baoshan Wang ◽

Wei Yang ◽

Weitao Wang ◽

...

Keyword(s):

Large Volume ◽

Seismic Data ◽

Temporal Changes ◽

Air Pressure ◽

Southwestern China ◽

Long Period ◽

Air Gun ◽

Velocity Variations ◽

Velocity Changes ◽

Source Array

Abstract Temporal changes of seismic velocities in the Earth’s crust can be induced by stress perturbations or material damage from reasons such as strong ground motion, volcanic activities, and atmospheric effects. However, monitoring the temporal changes remains challenging, because most of them generally exist in small travel-time differences of seismic data. Here, we present an excellent case of daily variations of the subsurface structure detected using a large-volume air-gun source array of one-month experiment in Binchuan, Yunnan, southwestern China. The seismic data were recorded by 12 stations within ∼10 km away from the source and used to detect velocity change in the crust using the deconvolution method and sliding window cross-correlation method, which can eliminate the “intercept” error when cutting the air-gun signals and get the real subsurface variations. Furthermore, the multichannel singular spectral analysis method is used to separate the daily change (∼1 cycle per day) from the “long-period” change (<1 cycle per day) or noise. The result suggests that the daily velocity changes at the two nearest stations, 53277 (offset ∼700 m) and 53278 (offset ∼2.3 km), are well correlated with air temperature variation with a time lag of 5.0 ± 1.5 hr, which reflects that the velocity variations at the subsurface are likely attributed to thermoelastic strain. In contrast, both daily and long-period velocity changes at distant stations correlate better with the varying air pressure than the temperature, indicating that the velocity variations at deeper depth are dominated by the elastic loading of air pressure. Our results demonstrate that the air-gun source is a powerful tool to detect the velocity variation of the shallow crust media.

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Radial Velocity Measurements of Twenty-One Long-Period Variable Stars

Publications of the Astronomical Society of the Pacific ◽

10.1086/128198 ◽

1965 ◽

Vol 77 ◽

pp. 214 ◽

Cited By ~ 2

Author(s):

Charles L. Perry ◽

William P. Bidelman

Keyword(s):

Radial Velocity ◽

Variable Stars ◽

Velocity Measurements ◽

Long Period ◽

Period Variable

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Long-period radial velocity variations in three K giants

The Astrophysical Journal ◽

10.1086/173002 ◽

1993 ◽

Vol 413 ◽

pp. 339 ◽

Cited By ~ 106

Author(s):

Artie P. Hatzes ◽

William D. Cochran

Keyword(s):

Radial Velocity ◽

Long Period ◽

Velocity Variations ◽

K Giants

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/201321863 ◽

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

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Two new double-lined spectroscopic binary white dwarfs

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa466 ◽

2020 ◽

Vol 493 (2) ◽

pp. 2805-2816 ◽

Cited By ~ 1

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.

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Bright Giants with Small Amplitude Long Period Velocity Variability

International Astronomical Union Colloquium ◽

10.1017/s0252921100098912 ◽

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.

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Coravel Measurements of IAU and Southern Potential Radial-Velocity Standard Stars. A Zero Point Discussion

International Astronomical Union Colloquium ◽

10.1017/s0252921100098924 ◽

1984 ◽

Vol 88 ◽

pp. 299-310

Author(s):

M. Mayor ◽

E. Maurice

Keyword(s):

Radial Velocity ◽

Observational Data ◽

Zero Point ◽

Variable Stars ◽

Radial Velocities ◽

Variable Velocity ◽

Velocity Measurements ◽

Similar Difference ◽

Systematic Effects ◽

Velocity Variations

AbstractRadial velocity measurements have been carried out since 1981 with the spectrometer CORAVEL at ESO, La Silla. Almost one thousand measurements of IAU radial velocity standard stars and of potential southern standard stars have been acquired by the different observers (mean precision per measurement 0.2 km/s).Among the measured IAU standard stars, at least four have shown clear radial-velocity variations from 1981 to 1984 (HD 36673, 156014, 44131, 115521).The comparison between CORAVEL mean velocities and IAU values reveals a difference of approximately 0.8 km/s between bright (mv <4.3) and faint IAU (mv >4.3) standards (Vr(IAUB) - Vr(IAUF) = +0.8 km/s). A similar difference also appears when comparing IAU standard velocities and those measured with the Victoria spectrometer, Fletcher et al. (1982).Thus, IAU standard stars not only include radial-velocity variable stars (intrinsic variables and SB) but they also present zero-point systematic effects.In the present paper we correct the radial velocities of the bright IAU standard stars so that they now belong to the same system as the faint ones. After elimination of variable velocity stars and stars showing large differences between IAU values and recent radial-velocity determinations, an homogeneous list of 34 IAU standard stars is obtained. These revised radial velocities are based on IAU values and new determinations obtained with the Victoria spectrometer and with CORAVEL at La Silla. These stars are distributed between the declinations δ = -82° and δ = +28°.This paper uses observational data in advance of the publication by CORAVEL observers of the 7th of the series of papers: “Radial velocities of southern stars obtained with the photoelectric scanner CORAVEL”.

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The Interpretation of Radial Velocity Observations of Long Period Variable Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100073425 ◽

1979 ◽

Vol 46 ◽

pp. 199-213

Author(s):

L. A. Willson

Keyword(s):

Radial Velocity ◽

Velocity Structure ◽

Theoretical Models ◽

Variable Stars ◽

Observational Constraints ◽

The Third ◽

Long Period ◽

General Mass ◽

Period Variable ◽

Velocity Information

The first part of this paper contains a synthesis of the results of numerical and analytical theoretical models for the velocity structure of the atmospheres of the long period variable stars (LPVs). The details of these derivations have been presented elsewhere (Willson and Hill 1978; Hill and Willson 1978). The discussion of the models in this paper is therefore limited to summarizing the earlier results in a form appropriate to the interpretation of observed velocities. In the second part of the paper the methods described in the first part are applied to five stars with periods ranging from 150dto 407d, and masses and radii are derived from velocity information for each of these stars. In the third section a general mass-radius relationship for the long period variable stars is derived from these points and compared to independent observational constraints.

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