Fundamental Properties and Distances of Large Magellanic Cloud Eclipsing Binaries. IV. HV 5936

Fitzpatrick, E. L.; Ribas, I.; Guinan, E. F.; Maloney, F. P.; Claret, A.

doi:10.1086/368309

Cited by 90 publications

(95 citation statements)

References 35 publications

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“…On one hand these are average distances. Distance determinations from several eclipsing binaries in the LMC suggest that there is a considerable depth along the line of sight (Fitzpatrick et al 2003). The SMC is also known to be very extended along the line of sight, with many estimates well in excess of 10 kpc (Mathewson et al 1986;Crowl et al 2001).…”

Section: Distance Modulusmentioning

confidence: 99%

Circumstellar emission in Be/X-ray binaries of the Magellanic Clouds and the Milky Way

Riquelme

Torrejón

Negueruela

2012

A&A

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Aims. We study the optical and near-infrared colour excesses produced by circumstellar emission in a sample of Be/X-ray binaries. Our main goals are exploring whether previously published relations, valid for isolated Be stars, are applicable to Be/X-ray binaries and computing the distance to these systems after correcting for the effects of the circumstellar contamination. Methods. Simultaneous UBVRI photometry and spectra in the 3500−7000 Å spectral range were obtained for 11 optical counterparts to Be/X-ray binaries in the LMC, 5 in the SMC and 12 in the Milky Way. As a measure of the amount of circumstellar emission we used the H α equivalent width corrected for photospheric absorption. Results. We find a linear relationship between the strength of the H α emission line and the component of E(B − V) originating from the circumstellar disk. This relationship is valid for stars with emission lines weaker than EW ≈ −15 Å. Beyond this point, the circumstellar contribution to E(B − V) saturates at a value ≈0.17 mag. A similar relationship is found for the (V − I) near infrared colour excess, albeit with a steeper slope and saturation level. The circumstellar excess in (B − V) is found to be about five times higher for Be/X-ray binaries than for isolated Be stars with the same equivalent width EW(H α ), implying significant differences in the physical properties of their circumstellar envelopes. The distance to Be/X-ray binaries (with non-shell Be star companions) can only be correctly estimated by taking into account the excess emission in the V band produced by free-free and free-bound transitions in the circumstellar envelope. We provide a simple method to determine the distances that includes this effect.

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Section: Distance Modulusmentioning

confidence: 99%

Circumstellar emission in Be/X-ray binaries of the Magellanic Clouds and the Milky Way

Riquelme

Torrejón

Negueruela

2012

A&A

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“…Quasi-geometric distances from detached eclipsing binary systems (Fitzpatrick et al 2003;Pietrzynski et al 2009;Bonanos et al 2011) lead to a mean distance modulus of 18.49 ± 0.04 mag. Several of these individual studies quote internal errors of less than 0.05 mag, so we are presently in a situation where systematic (calibration) errors dominate.…”

Section: The Hb Luminosity-metallicity Relationmentioning

confidence: 99%

The horizontal branch luminosity vs. metallicity in M 31 globular clusters

Federici

Cacciari

Bellazzini

et al. 2012

A&A

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Context. Thanks to the outstanding capabilites of the HS T , our current knowledge about the M31 globular clusters (GCs) is similar to our knowledge of the Milky Way GCs in the 1960s-1970s, which set the basis for studying the halo and galaxy formation using these objects as tracers, and established their importance in defining the cosmic distance scale. Aims. We intend to derive a new calibration of the M V (HB)-[Fe/H] relation by exploiting the large photometric database of old GCs in M31 in the HS T archive. Methods. We collected the BVI data for 48 old GCs in M31 and analysed them by applying the same methods and procedures to all objects. We obtained a set of homogeneous colour-magnitude diagrams (CMDs) that were best-fitted with the fiducial CMD ridge lines of selected Milky Way template GCs. Reddening, metallicity, Horizontal Branch (HB) luminosity and distance were determined self-consistently for each cluster. Results. There are three main results of this study: i) the relation M V (HB)=0.25(±0.02)[Fe/H]+0.89(±0.03), which is obtained from the above parameters and is calibrated on the distances of the template Galactic GCs; ii) the distance modulus to M31 of (m-M) 0 =24.42±0.06 mag, obtained by normalising this relation at the reference value of [Fe/H]=-1.5 to a similar relation using V 0 (HB). This is the first determination of the distance to M31 based on the characteristics of its GC system which is calibrated on Galactic GCs; iii) the distance to the Large Magellanic Cloud (LMC), which is estimated to be 18.54±0.07 mag as a consequence of the previous results. These values agree excellently with the most recent estimate based on HS T parallaxes of Galactic Cepheid and RR Lyrae stars, as well as with recent methods.

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“…where j (φ), the flux of component j in a given passband normalized by the value at quadrature, accounts for possible out-ofeclipse variability due to departure from sphericity and reflection effects (Fitzpatrick et al 2003); L λ is the ratio of the continuum monochromatic luminosities, i.e. the ratio of the mean surface brightnesses J j,λ times the ratio of radii squared,…”

Section: Synthetic Spectramentioning

confidence: 99%

“…As photometry is only half the story, high-resolution spectrographs attached to 4-m class or larger telescopes had to be used to obtain reliable radial velocity (RV) curves. Four B-type EB systems belonging to the Large Magellanic Cloud (LMC) were accurately characterized in a series of papers from Guinan et al (1998), Ribas et al (2000Ribas et al ( , 2002 and Fitzpatrick et al (2002Fitzpatrick et al ( , 2003. More recently, from high resolution, high S /N spectra obtained with UVES at the ESO VLT, the analysis of eight more LMC systems was presented by González et al (2005).…”

Section: Introductionmentioning

confidence: 99%

VLT multi-object spectroscopy of 33 eclipsing binaries in the Small Magellanic Cloud

North¹,

Gauderon²,

Barblan

et al. 2010

A&A

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Aims. Our purpose is to provide reliable stellar parameters for a significant sample of eclipsing binaries, which are representative of a whole dwarf and metal-poor galaxy. We also aim at providing a new estimate of the mean distance to the SMC and of its depth along the line of sight for the observed field of view. Methods. We use radial velocity curves obtained with the ESO FLAMES facility at the VLT and light curves from the OGLE-II photometric survey. The radial velocities were obtained by least-squares fits of the observed spectra to synthetic ones, excluding the hydrogen Balmer lines. Results. Our sample contains 23 detached, 9 semi-detached and 1 overcontact systems. Most detached systems have properties consistent with stellar evolution calculations from single-star models at the standard SMC metalicity Z = 0.004, though they tend to be slightly overluminous. The few exceptions are probably due to third-light contribution or insufficient signal-to-noise ratio. The mass ratios are consistent with a flat distribution, both for detached and semi-detached/contact binaries. A mass-luminosity relation valid from ∼4 to ∼18 M is derived. The uncertainties are in the ±2 to ±11% range for the masses, in the ±2 to ±5% range for the radii and in the ±1 to ±6% range for the effective temperatures. The average distance modulus is 19.11 ± 0.03 (66.4 ± 0.9 kpc). The moduli derived from the V and from the I data are consistent within 0.01 mag. The 2σ depth of the SMC is, for our field, of 0.25 mag or 7.6 kpc under the assumption of a Gaussian distribution of stars along the line of sight. Three systems show significant apsidal motion, one of them with an apsidal period of 7.6 years, the shortest known to date for a detached system with main sequence stars.

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Fundamental Properties and Distances of Large Magellanic Cloud Eclipsing Binaries. IV. HV 5936

Cited by 90 publications

References 35 publications

Circumstellar emission in Be/X-ray binaries of the Magellanic Clouds and the Milky Way

Circumstellar emission in Be/X-ray binaries of the Magellanic Clouds and the Milky Way

The horizontal branch luminosity vs. metallicity in M 31 globular clusters

VLT multi-object spectroscopy of 33 eclipsing binaries in the Small Magellanic Cloud

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