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Claud Sandberg H Lacy - One of the best experts on this subject based on the ideXlab platform.

  • absolute properties of the pre main sequence eclipsing Binary Star np persei
    The Astronomical Journal, 2016
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, K Pavlovski, Francis C Fekel, Matthew W Muterspaugh
    Abstract:

    NP Per is a well-detached, 2.2 day eclipsing Binary whose components are both pre-main-sequence Stars that are still contracting toward the main-sequence phase of evolution. We report extensive photometric and spectroscopic observations with which we have determined their properties accurately. Their surface temperatures are quite different: 6420 ± 90 K for the larger F5 primary Star and 4540 ± 160 K for the smaller K5e Star. Their masses and radii are 1.3207 ± 0.0087 solar masses and 1.372 ± 0.013 solar radii for the primary, and 1.0456 ± 0.0046 solar masses and 1.229 ± 0.013 solar radii for the secondary. The orbital period is variable over long periods of time. A comparison of the observations with current stellar evolution models from MESA indicates that the Stars cannot be fit at a single age: the secondary appears significantly younger than the primary. If the Stars are assumed to be coeval and to have the age of the primary (17 Myr), then the secondary is larger and cooler than predicted by current models. The Hα spectral line of the secondary component is completely filled by, presumably, chromospheric emission due to a magnetic activity cycle.

  • absolute properties of the main sequence eclipsing Binary Star gx geminorum constraints on convective core overshooting
    The Astronomical Journal, 2008
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret
    Abstract:

    We present 12,155 new differential photometric observations in the V filter made with the Undergraduate Research Studies in Astronomy and NF\Observatory WebScopes, as well as 33 radial velocities from spectroscopic observations of the detached, 4.04 day double-lined eclipsing Binary Star GX Gem. Absolute dimensions of the components are determined from these new, and also from previously published, data with high precision (less than 0.7% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.488 ? 0.011 solar masses and 2.327 ? 0.012 solar radii for the primary, and 1.467 ? 0.010 solar masses and 2.238 ? 0.012 solar radii for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from the spectra, uvby?, and UBV photometry: 6195 ? 100 K for the primary, 6165 ? 100 K for the secondary, corresponding to spectral types of F7 and F7 V, and 0.068 mag for the color excess Eb ? y . Spectral line widths give rotational velocities that are synchronous with the mean orbital motion in a circular orbit. The components of GX Gem are relatively old main-sequence Stars with an age of about 2.8 billion years according to models. Because the components are located right at the end of their main-sequence evolutionary paths, we can place good limits on the convective core overshooting parameter. The lowest value of ?ov consistent with the observations would appear to be approximately ?ov = 0.18. Two different theories of tidal synchronization and circularization agree that the components should be synchronously rotating, but disagree about whether or not the orbits should be circular.

  • absolute properties of the main sequence eclipsing Binary Star ey cephei
    The Astronomical Journal, 2006
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, John Menke
    Abstract:

    We present 6907 differential photometric observations in the V filter, as well as 52 radial velocities from spectroscopic observations of the detached, eccentric 7.97 day double-lined eclipsing Binary Star EY Cep. Absolute dimensions of the components are determined with high precision (less than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.523 ± 0.008 M⊙ and 1.463 ± 0.010 R⊙ for the primary and 1.498 ± 0.014 M⊙ and 1.468 ± 0.010 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from the spectra, uvbyβ, and UBV photometry: 7090 ± 150 K for the primary and 6970 ± 150 K for the secondary, corresponding to spectral types of F0 and F0, and 0.036 mag for the color excess Eb-y. Spectral line widths give rotational velocities that are synchronous with the mean orbital motion in a highly eccentric orbit (e = 0.4429). The components of EY Cep are young main-sequence Stars with an age of about 40 million years, according to models.

  • absolute properties of the main sequence eclipsing Binary Star bp vulpeculae
    The Astronomical Journal, 2003
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present 5236 differential observations in the V filter measured by a robotic telescope, as well as radial velocities from spectroscopic observations, of the detached, eccentric 1.9 day double-lined eclipsing Binary Star BP Vul. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.737 ± 0.015 M⊙ and 1.852 ± 0.014 R⊙ for the primary, and 1.408 ± 0.009 M⊙ and 1.489 ± 0.014 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from uvbyβ photometry: 7700 ± 150 K for the primary, 6800 ± 150 K for the secondary—corresponding to spectral types of A7m and F2m—and 0.022 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvbyβ photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion for the secondary component, but subsynchronous for the primary component, in a slightly eccentric orbit (e = 0.0345). Apsidal motion based on times of minimum light appears to be negative with a period of about 75 years based on recent observations of minima, but this result is not confirmed by the radial velocity measurements, and it is indeterminate when older photographic and visual data are included. The components of BP Vul are main-sequence Stars with an age of about 1 Gyr according to models.

  • absolute properties of the main sequence eclipsing Binary Star ww camelopardalis
    The Astronomical Journal, 2002
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present absolute photometric observations in uvby? and 5759 differential observations in the V filter (the most complete light curve ever obtained) measured by a robotic telescope, as well as radial velocities from spectroscopic observations of the detached, eccentric, 2.3 day, double-lined, eclipsing Binary Star WW Camelopardalis. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.920 ? 0.013 M? and 1.911 ? 0.016 R? for the primary, and 1.873 ? 0.018 M? and 1.808 ? 0.014 R? for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from new uvby? photometry: 8350 ? 135 K for the primary and 8240 ? 135 K for the secondary, corresponding to a spectral type of A4m for both, and 0.294 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvby? photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion in a slightly eccentric orbit (e = 0.0098). The components of WW Cam are main-sequence Stars with an age of about 490 Myr according to models.

Jeffrey A Sabby - One of the best experts on this subject based on the ideXlab platform.

  • absolute properties of the main sequence eclipsing Binary Star bp vulpeculae
    The Astronomical Journal, 2003
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present 5236 differential observations in the V filter measured by a robotic telescope, as well as radial velocities from spectroscopic observations, of the detached, eccentric 1.9 day double-lined eclipsing Binary Star BP Vul. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.737 ± 0.015 M⊙ and 1.852 ± 0.014 R⊙ for the primary, and 1.408 ± 0.009 M⊙ and 1.489 ± 0.014 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from uvbyβ photometry: 7700 ± 150 K for the primary, 6800 ± 150 K for the secondary—corresponding to spectral types of A7m and F2m—and 0.022 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvbyβ photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion for the secondary component, but subsynchronous for the primary component, in a slightly eccentric orbit (e = 0.0345). Apsidal motion based on times of minimum light appears to be negative with a period of about 75 years based on recent observations of minima, but this result is not confirmed by the radial velocity measurements, and it is indeterminate when older photographic and visual data are included. The components of BP Vul are main-sequence Stars with an age of about 1 Gyr according to models.

  • absolute properties of the main sequence eclipsing Binary Star ww camelopardalis
    The Astronomical Journal, 2002
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present absolute photometric observations in uvby? and 5759 differential observations in the V filter (the most complete light curve ever obtained) measured by a robotic telescope, as well as radial velocities from spectroscopic observations of the detached, eccentric, 2.3 day, double-lined, eclipsing Binary Star WW Camelopardalis. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.920 ? 0.013 M? and 1.911 ? 0.016 R? for the primary, and 1.873 ? 0.018 M? and 1.808 ? 0.014 R? for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from new uvby? photometry: 8350 ? 135 K for the primary and 8240 ? 135 K for the secondary, corresponding to a spectral type of A4m for both, and 0.294 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvby? photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion in a slightly eccentric orbit (e = 0.0098). The components of WW Cam are main-sequence Stars with an age of about 490 Myr according to models.

Guillermo Torres - One of the best experts on this subject based on the ideXlab platform.

  • absolute properties of the pre main sequence eclipsing Binary Star np persei
    The Astronomical Journal, 2016
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, K Pavlovski, Francis C Fekel, Matthew W Muterspaugh
    Abstract:

    NP Per is a well-detached, 2.2 day eclipsing Binary whose components are both pre-main-sequence Stars that are still contracting toward the main-sequence phase of evolution. We report extensive photometric and spectroscopic observations with which we have determined their properties accurately. Their surface temperatures are quite different: 6420 ± 90 K for the larger F5 primary Star and 4540 ± 160 K for the smaller K5e Star. Their masses and radii are 1.3207 ± 0.0087 solar masses and 1.372 ± 0.013 solar radii for the primary, and 1.0456 ± 0.0046 solar masses and 1.229 ± 0.013 solar radii for the secondary. The orbital period is variable over long periods of time. A comparison of the observations with current stellar evolution models from MESA indicates that the Stars cannot be fit at a single age: the secondary appears significantly younger than the primary. If the Stars are assumed to be coeval and to have the age of the primary (17 Myr), then the secondary is larger and cooler than predicted by current models. The Hα spectral line of the secondary component is completely filled by, presumably, chromospheric emission due to a magnetic activity cycle.

  • absolute properties of the main sequence eclipsing Binary Star gx geminorum constraints on convective core overshooting
    The Astronomical Journal, 2008
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret
    Abstract:

    We present 12,155 new differential photometric observations in the V filter made with the Undergraduate Research Studies in Astronomy and NF\Observatory WebScopes, as well as 33 radial velocities from spectroscopic observations of the detached, 4.04 day double-lined eclipsing Binary Star GX Gem. Absolute dimensions of the components are determined from these new, and also from previously published, data with high precision (less than 0.7% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.488 ? 0.011 solar masses and 2.327 ? 0.012 solar radii for the primary, and 1.467 ? 0.010 solar masses and 2.238 ? 0.012 solar radii for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from the spectra, uvby?, and UBV photometry: 6195 ? 100 K for the primary, 6165 ? 100 K for the secondary, corresponding to spectral types of F7 and F7 V, and 0.068 mag for the color excess Eb ? y . Spectral line widths give rotational velocities that are synchronous with the mean orbital motion in a circular orbit. The components of GX Gem are relatively old main-sequence Stars with an age of about 2.8 billion years according to models. Because the components are located right at the end of their main-sequence evolutionary paths, we can place good limits on the convective core overshooting parameter. The lowest value of ?ov consistent with the observations would appear to be approximately ?ov = 0.18. Two different theories of tidal synchronization and circularization agree that the components should be synchronously rotating, but disagree about whether or not the orbits should be circular.

  • absolute properties of the main sequence eclipsing Binary Star ey cephei
    The Astronomical Journal, 2006
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, John Menke
    Abstract:

    We present 6907 differential photometric observations in the V filter, as well as 52 radial velocities from spectroscopic observations of the detached, eccentric 7.97 day double-lined eclipsing Binary Star EY Cep. Absolute dimensions of the components are determined with high precision (less than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.523 ± 0.008 M⊙ and 1.463 ± 0.010 R⊙ for the primary and 1.498 ± 0.014 M⊙ and 1.468 ± 0.010 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from the spectra, uvbyβ, and UBV photometry: 7090 ± 150 K for the primary and 6970 ± 150 K for the secondary, corresponding to spectral types of F0 and F0, and 0.036 mag for the color excess Eb-y. Spectral line widths give rotational velocities that are synchronous with the mean orbital motion in a highly eccentric orbit (e = 0.4429). The components of EY Cep are young main-sequence Stars with an age of about 40 million years, according to models.

  • absolute properties of the main sequence eclipsing Binary Star bp vulpeculae
    The Astronomical Journal, 2003
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present 5236 differential observations in the V filter measured by a robotic telescope, as well as radial velocities from spectroscopic observations, of the detached, eccentric 1.9 day double-lined eclipsing Binary Star BP Vul. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.737 ± 0.015 M⊙ and 1.852 ± 0.014 R⊙ for the primary, and 1.408 ± 0.009 M⊙ and 1.489 ± 0.014 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from uvbyβ photometry: 7700 ± 150 K for the primary, 6800 ± 150 K for the secondary—corresponding to spectral types of A7m and F2m—and 0.022 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvbyβ photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion for the secondary component, but subsynchronous for the primary component, in a slightly eccentric orbit (e = 0.0345). Apsidal motion based on times of minimum light appears to be negative with a period of about 75 years based on recent observations of minima, but this result is not confirmed by the radial velocity measurements, and it is indeterminate when older photographic and visual data are included. The components of BP Vul are main-sequence Stars with an age of about 1 Gyr according to models.

  • absolute properties of the main sequence eclipsing Binary Star ww camelopardalis
    The Astronomical Journal, 2002
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present absolute photometric observations in uvby? and 5759 differential observations in the V filter (the most complete light curve ever obtained) measured by a robotic telescope, as well as radial velocities from spectroscopic observations of the detached, eccentric, 2.3 day, double-lined, eclipsing Binary Star WW Camelopardalis. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.920 ? 0.013 M? and 1.911 ? 0.016 R? for the primary, and 1.873 ? 0.018 M? and 1.808 ? 0.014 R? for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from new uvby? photometry: 8350 ? 135 K for the primary and 8240 ? 135 K for the secondary, corresponding to a spectral type of A4m for both, and 0.294 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvby? photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion in a slightly eccentric orbit (e = 0.0098). The components of WW Cam are main-sequence Stars with an age of about 490 Myr according to models.

Antonio Claret - One of the best experts on this subject based on the ideXlab platform.

  • absolute properties of the main sequence eclipsing Binary Star gx geminorum constraints on convective core overshooting
    The Astronomical Journal, 2008
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret
    Abstract:

    We present 12,155 new differential photometric observations in the V filter made with the Undergraduate Research Studies in Astronomy and NF\Observatory WebScopes, as well as 33 radial velocities from spectroscopic observations of the detached, 4.04 day double-lined eclipsing Binary Star GX Gem. Absolute dimensions of the components are determined from these new, and also from previously published, data with high precision (less than 0.7% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.488 ? 0.011 solar masses and 2.327 ? 0.012 solar radii for the primary, and 1.467 ? 0.010 solar masses and 2.238 ? 0.012 solar radii for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from the spectra, uvby?, and UBV photometry: 6195 ? 100 K for the primary, 6165 ? 100 K for the secondary, corresponding to spectral types of F7 and F7 V, and 0.068 mag for the color excess Eb ? y . Spectral line widths give rotational velocities that are synchronous with the mean orbital motion in a circular orbit. The components of GX Gem are relatively old main-sequence Stars with an age of about 2.8 billion years according to models. Because the components are located right at the end of their main-sequence evolutionary paths, we can place good limits on the convective core overshooting parameter. The lowest value of ?ov consistent with the observations would appear to be approximately ?ov = 0.18. Two different theories of tidal synchronization and circularization agree that the components should be synchronously rotating, but disagree about whether or not the orbits should be circular.

  • absolute properties of the main sequence eclipsing Binary Star ey cephei
    The Astronomical Journal, 2006
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, John Menke
    Abstract:

    We present 6907 differential photometric observations in the V filter, as well as 52 radial velocities from spectroscopic observations of the detached, eccentric 7.97 day double-lined eclipsing Binary Star EY Cep. Absolute dimensions of the components are determined with high precision (less than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.523 ± 0.008 M⊙ and 1.463 ± 0.010 R⊙ for the primary and 1.498 ± 0.014 M⊙ and 1.468 ± 0.010 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from the spectra, uvbyβ, and UBV photometry: 7090 ± 150 K for the primary and 6970 ± 150 K for the secondary, corresponding to spectral types of F0 and F0, and 0.036 mag for the color excess Eb-y. Spectral line widths give rotational velocities that are synchronous with the mean orbital motion in a highly eccentric orbit (e = 0.4429). The components of EY Cep are young main-sequence Stars with an age of about 40 million years, according to models.

  • absolute properties of the main sequence eclipsing Binary Star bp vulpeculae
    The Astronomical Journal, 2003
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present 5236 differential observations in the V filter measured by a robotic telescope, as well as radial velocities from spectroscopic observations, of the detached, eccentric 1.9 day double-lined eclipsing Binary Star BP Vul. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.737 ± 0.015 M⊙ and 1.852 ± 0.014 R⊙ for the primary, and 1.408 ± 0.009 M⊙ and 1.489 ± 0.014 R⊙ for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from uvbyβ photometry: 7700 ± 150 K for the primary, 6800 ± 150 K for the secondary—corresponding to spectral types of A7m and F2m—and 0.022 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvbyβ photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion for the secondary component, but subsynchronous for the primary component, in a slightly eccentric orbit (e = 0.0345). Apsidal motion based on times of minimum light appears to be negative with a period of about 75 years based on recent observations of minima, but this result is not confirmed by the radial velocity measurements, and it is indeterminate when older photographic and visual data are included. The components of BP Vul are main-sequence Stars with an age of about 1 Gyr according to models.

  • absolute properties of the main sequence eclipsing Binary Star ww camelopardalis
    The Astronomical Journal, 2002
    Co-Authors: Claud Sandberg H Lacy, Guillermo Torres, Antonio Claret, Jeffrey A Sabby
    Abstract:

    We present absolute photometric observations in uvby? and 5759 differential observations in the V filter (the most complete light curve ever obtained) measured by a robotic telescope, as well as radial velocities from spectroscopic observations of the detached, eccentric, 2.3 day, double-lined, eclipsing Binary Star WW Camelopardalis. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.920 ? 0.013 M? and 1.911 ? 0.016 R? for the primary, and 1.873 ? 0.018 M? and 1.808 ? 0.014 R? for the secondary. The effective temperatures and interstellar reddening of the Stars are accurately determined from new uvby? photometry: 8350 ? 135 K for the primary and 8240 ? 135 K for the secondary, corresponding to a spectral type of A4m for both, and 0.294 mag for Eb-y. The metallic-lined character of the Stars is revealed by high-resolution spectroscopy and uvby? photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion in a slightly eccentric orbit (e = 0.0098). The components of WW Cam are main-sequence Stars with an age of about 490 Myr according to models.

Leonid M Ozernoy - One of the best experts on this subject based on the ideXlab platform.

  • post newtonian theory for precision doppler measurements of Binary Star orbits
    The Astrophysical Journal, 1999
    Co-Authors: S M Kopeikin, Leonid M Ozernoy
    Abstract:

    The determination of velocities of Stars from precise Doppler measurements is described here using a relativistic theory of astronomical reference frames to determine the Keplerian and post-Keplerian parameters of Binary systems. Seven reference frames are introduced: (1) the proper frame of a particle emitting light, (2) the Star-centered reference frame, (3) the barycentric frame of the Binary, (4) the barycentric frame of the Galaxy, (5) the barycentric frame of the solar system, (6) the geocentric frame, and (7) the topocentric frame of observer at the Earth. We apply successive Lorentz transformations and the relativistic equation of light propagation to establish the exact treatment of Doppler effect in Binary systems both in special and general relativity theories. As a result, the Doppler shift is a sum of (1) linear in c-1 terms, which include the ordinary Doppler effect and its variation due to the secular radial acceleration of the Binary with respect to observer; (2) terms proportional to c-2, which include the contributions from the quadratic Doppler effect caused by the relative motion of Binary Star with respect to the solar system, the motion of the particle emitting light and diurnal rotational motion of observer, orbital motion of the Star around the Binary's barycenter, and the orbital motion of the Earth; and (3) terms proportional to c-2, which include the contributions from redshifts due to gravitational fields of the Star, the Star's companion, the Galaxy, the solar system, and the Earth. After parameterization of the Binary's orbit, we find that the presence of periodically changing terms in the Doppler shift enables us to disentangle different terms and measure, along with the well-known Keplerian parameters of the Binary, four additional post-Keplerian parameters, which characterize (1) the relativistic advance of the periastron; (2) a combination of the quadratic Doppler and gravitational shifts associated with the orbital motion of the primary relative to the Binary's barycenter and the companion's gravitational field, respectively; (3) the amplitude of the "gravitational lensing" contribution to the Doppler shift; and (4) the usual inclination angle of the Binary's orbit, i. We briefly discuss the feasibility of practical implementation of these theoretical results, which crucially depends on further progress in the technique of precision Doppler measurements.

  • post newtonian theory for precision doppler measurements of Binary Star orbits
    arXiv: Astrophysics, 1998
    Co-Authors: S M Kopeikin, Leonid M Ozernoy
    Abstract:

    The determination of velocities of Stars from precise Doppler measurements is described here using relativistic theory of astronomical reference frames so as to determine the Keplerian and post-Keplerian parameters of Binary systems. We apply successive Lorentz transformations and the relativistic equation of light propagation to establish the exact treatment of Doppler effect in Binary systems both in special and general relativity theories. As a result, the Doppler shift is a sum of (1) linear in $c^{-1}$ terms, which include the ordinary Doppler effect and its variation due to the secular radial acceleration of the Binary with respect to observer; (2) terms proportional to $c^{-2}$, which include the contributions from the quadratic Doppler effect caused by the relative motion of Binary Star with respect to the Solar system, motion of the particle emitting light and diurnal rotational motion of observer, orbital motion of the Star around the Binary's barycenter, and orbital motion of the Earth; and (3) terms proportional to $c^{-2}$, which include the contributions from redshifts due to gravitational fields of the Star, Star's companion, Galaxy, Solar system, and the Earth. After parameterization of the Binary's orbit we find that the presence of periodically changing terms in the Doppler schift enables us disentangling different terms and measuring, along with the well known Keplerian parameters of the Binary, four additional post-Keplerian parameters, including the inclination angle of the Binary's orbit, $i$. We briefly discuss feasibility of practical implementation of these theoretical results, which crucially depends on further progress in the technique of precision Doppler measurements.