scholarly journals Finding binaries from phase modulation of pulsating stars with Kepler – IV. Detection limits and radial velocity verification

2016 ◽  
Vol 461 (4) ◽  
pp. 4215-4226 ◽  
Author(s):  
Simon J. Murphy ◽  
Hiromoto Shibahashi ◽  
Timothy R. Bedding
Keyword(s):  
Radial Velocity ◽  
Phase Modulation ◽  
Detection Limits ◽  
Pulsating Stars

scholarly journals Finding binaries among Kepler pulsating stars from phase modulation of their pulsations

2014 ◽  
Vol 441 (3) ◽  
pp. 2515-2527 ◽  
Author(s):  
S. J. Murphy ◽  
T. R. Bedding ◽  
H. Shibahashi ◽  
D. W. Kurtz ◽  
H. Kjeldsen
Keyword(s):  
Phase Modulation ◽  
Pulsating Stars

scholarly journals Asteroseismic search for invisible binary companions

2015 ◽  
Vol 11 (A29B) ◽  
pp. 642-647
Author(s):  
Hiromoto Shibahashi ◽  
Simon J. Murphy ◽  
Donald W. Kurtz
Keyword(s):  
Radial Velocity ◽  
Frequency Modulation ◽  
Binary Systems ◽  
Binary Star ◽  
Orbital Parameters ◽  
Pulsating Stars ◽  
Kepler Mission ◽  
Orbital Frequency ◽  
Long Time ◽  
The Fourier Transform

AbstractContinuous and precise space-based photometry has made it possible to measure the orbital frequency modulation of pulsating stars in binary systems with extremely high precision over long time spans. We present the phase modulation (PM) method for finding binaries among pulsating stars. We demonstrate how the orbital elements of a pulsating binary star can be obtained analytically from photometry alone, without spectroscopic radial velocity measurement. Frequency modulation (FM) caused by binary orbital motion also manifests itself in the Fourier transform, as a multiplet with equal spacing of the orbital frequency. The orbital parameters can also be extracted by analysing the amplitudes and phases of the peaks in these multiplets. We derive analytically the theoretical relations between the multiplet properties and the orbital parameters, and present a method for determining these parameters, including the eccentricity and the argument of periapsis. This, too, is achievable with the photometry alone, without spectroscopic radial velocity measurements. We apply these two methods to Kepler mission data and demonstrate that the results are in good agreement with each other. These methods are used to search for invisible binary companions, including planets and invisible massive objects such as neutron stars and stellar-mass black holes.

scholarly journals The empirical period-radius relation for pulsating stars: a synthesis based on photometric and radial velocity measurements

1986 ◽  
Vol 118 ◽  
pp. 273-274
Author(s):  
G. Burki
Keyword(s):  
Radial Velocity ◽  
Stellar Evolution ◽  
Variable Stars ◽  
Radial Velocities ◽  
Velocity Measurements ◽  
Pulsating Stars ◽  
Powerful Test ◽  
The Mean

The relation existing between the radius and the period for the pulsating stars of a given class constitutes a powerful test for the theory of stellar evolution and for the identification of the pulsation modes. In recent years, several authors have determined the mean radius of a lot of pulsating stars of various classes by applying the Baade-Wesselink method. Fig. 1 presents the resulting general logP - logR diagram grouping these determinations. The sources for the radii are given by Burki and Meylan (1986). The variable stars in known binaries have been excluded since the presence of a companion biases the radius calculation (Burki, 1984). The determinations marked by arrows are based on the radial velocities by CORAVEL (1m telescope at the Haute-Provence Observatory, France) or/and on the photometry in the Geneva system (40cm and 70cm telescopes at La Silla Observatory, Chile).

scholarly journals Studies of Large-Amplitude δ Scuti Variables

1993 ◽  
Vol 139 ◽  
pp. 104-104
Author(s):  
W. J. F. Wilson ◽  
E. F. Milone ◽  
D. J. I. Fry
Keyword(s):  
Radial Velocity ◽  
Large Amplitude ◽  
Light Curves ◽  
Pulsating Stars ◽  
Modest Contribution ◽  
The Mean ◽  
Absolute Magnitudes ◽  
Scuti Stars ◽  
Radial Velocity Data

The determination of Baade-Wesselink radii and luminosities for pulsating stars are long-standing and highly desired goals since they provide the promise of being standard candles. In a modest contribution towards these goals, we have undertaken a programme to determine the radii and luminosities of the large-amplitude δ Scuti stars DY Herculis, EH Librae and DY Pegasi from optical and infrared photometry and cross-correlated radial velocity data. We use Fourier representations for V, I and J light curves and for the radial velocity curves in Baade-Wesselink analyses to derive minimum radii over the pulsation cycles. These radii and their errors and the mean bolometric luminosities and absolute magnitudes will be discussed here and in papers to follow. As a check, we also apply our method to the data and results of other groups.

scholarly journals Finding binaries from phase modulation of pulsating stars with Kepler – VI. Orbits for 10 new binaries with mischaracterized primaries

2020 ◽  
Vol 493 (4) ◽  
pp. 5382-5388
Author(s):  
Simon J Murphy ◽  
Nicholas H Barbara ◽  
Daniel Hey ◽  
Timothy R Bedding ◽  
Ben D Fulcher
Keyword(s):  
Phase Modulation ◽  
White Dwarfs ◽  
Binary Systems ◽  
Main Sequence ◽  
Classification Algorithm ◽  
Orbital Parameters ◽  
Pulsating Stars ◽  
Stellar Properties ◽  
Scuti Stars ◽  
Δ Scuti Stars

ABSTRACT Measuring phase modulation in pulsating stars has proven to be a highly successful way of finding binary systems. The class of pulsating main-sequence A and F variables, known as δ Scuti stars consists of particularly good targets for this, and the Kepler sample of these has been almost fully exploited. However, some Keplerδ Scuti stars have incorrect temperatures in stellar properties catalogues, and were missed in previous analyses. We used an automated pulsation classification algorithm to find 93 new δ Scuti pulsators among tens of thousands of F-type stars, which we then searched for phase modulation attributable to binarity. We discovered 10 new binary systems and calculated their orbital parameters, which we compared with those of binaries previously discovered in the same way. The results suggest that some of the new companions may be white dwarfs.

scholarly journals Finding binaries from phase modulation of pulsating stars with Kepler: V. Orbital parameters, with eccentricity and mass-ratio distributions of 341 new binaries

2017 ◽  
Vol 474 (4) ◽  
pp. 4322-4346 ◽  
Author(s):  
Simon J Murphy ◽  
Maxwell Moe ◽  
Donald W Kurtz ◽  
Timothy R Bedding ◽  
Hiromoto Shibahashi ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Mass Ratio ◽  
Orbital Parameters ◽  
Pulsating Stars

scholarly journals Occurrence rates of small planets from HARPS

2020 ◽  
Vol 643 ◽  
pp. A106
Author(s):  
D. Bashi ◽  
S. Zucker ◽  
V. Adibekyan ◽  
N. C. Santos ◽  
L. Tal-Or ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Detection Limits ◽  
Thick Disk ◽  
Occurrence Rate ◽  
Mass Detection ◽  
The Galaxy ◽  
Low Mass ◽  
Thin And Thick Disks ◽  
Thick Disks ◽  
Stellar Properties

Context. The stars in the Milky Way thin and thick disks can be distinguished by several properties such as metallicity and kinematics. It is not clear whether the two populations also differ in the properties of planets orbiting the stars. In order to study this, a careful analysis of both the chemical composition and mass detection limits is required for a sufficiently large sample. Currently, this information is still limited only to large radial-velocity (RV) programs. Based on the recently published archival database of the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph, we present a first analysis of low-mass (small) planet occurrence rates in a sample of thin- and thick-disk stars. Aims. We aim to assess the effects of stellar properties on planet occurrence rates and to obtain first estimates of planet occurrence rates in the thin and thick disks of the Galaxy. As a baseline for comparison, we also aim to provide an updated value for the small close-in planet occurrence rate and compare it with the results of previous RV and transit (Kepler) works. Methods. We used archival HARPS RV datasets to calculate detection limits of a sample of stars that were previously analysed for their elemental abundances. For stars with known planets we first subtracted the Keplerian orbit. We then used this information to calculate planet occurrence rates according to a simplified Bayesian model in different regimes of stellar and planet properties. Results. Our results suggest that metal-poor stars and more massive stars host fewer low-mass close-in planets. We find the occurrence rates of these planets in the thin and thick disks to be comparable. In the iron-poor regimes, we find these occurrence rates to be significantly larger at the high-α region (thick-disk stars) as compared with the low-α region (thin-disk stars). In general, we find the average number of close-in small planets (2–100 days, 1–20M⊕) per star (FGK-dwarfs) to be: n¯p = 0.36 ± 0.05, while the fraction of stars with planets is Fh = 0.23−0.03+0.04. Qualitatively, our results agree well with previous estimates based on RV and Kepler surveys. Conclusions. This work provides a first estimate of the close-in small planet occurrence rates in the solar neighbourhood of the thin and thick disks of the Galaxy. It is unclear whether there are other stellar properties related to the Galactic context that affect small-planet occurrence rates, or if it is only the combined effects of stellar metal content and mass. A future larger sample of stars and planets is needed to address those questions.

Introduction

2017 ◽  
Author(s):  
Sarbani Basu ◽  
William J. Chaplin
Keyword(s):  
Radial Velocity ◽  
Small Amplitude ◽  
Pulsating Stars ◽  
Stellar Pulsations ◽  
History Of ◽  
Solar Type

This chapter covers the basics of stellar pulsations, which are the main preoccupation of asteroseismology. Stellar pulsations may be detected by observing the variations of a star's brightness as a function of time. Radial velocity observations are also used in certain cases, though most pulsating stars have been studied using brightness variations. The focus of this chapter (and the book as a whole) is on stars with solar-like pulsations—the small-amplitude oscillations that are continually excited (in a stochastic manner) and damped by turbulence in the outer convection zones of the stars. In addition to a brief history of the study of solar-type oscillations, this chapter also provides an introduction to the basic appearance and properties of the pulsation spectra of solar-like oscillators.

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