[Paper Review] Light curve modeling of eclipsing binaries towards the constellation of Carina

Aniruddha Dey, Sukanta Deb+10 more|arXiv (Cornell University)|Feb 22, 2015

Stellar, planetary, and galactic studies26 references3 citations

TL;DR

This study presents detailed V-band photometric light curve modeling of 30 eclipsing binaries in the Carina constellation using data from the ESO VLT, employing the Wilson-Devinney code via PHOEBE to derive physical and geometrical parameters. The key finding is that 29 of the 30 systems are contact binaries, with mass ratios determined photometrically due to lack of spectroscopic data, significantly enhancing the extragalactic distance scale and Hubble constant calibration.

ABSTRACT

We present a detailed V-band photometric light curve modeling of 30 eclipsing binaries using the data from Pietrukowicz et al. (2009) collected with the European Southern Observatory Very Large Telescope (ESO VLT) of diameter 8-m. The light curve of these 30 eclipsing binaries were selected out of 148 of them available in the database on the basis of complete phase coverage, regular and smooth phased light curve shapes. Eclipsing binaries play pivotal role in the direct measurement of astronomical distances more accurately simply from their geometry of light curves. The accurate value of Hubble constant (H0) which measures the rate of expansion of the Universe heavily relies on extragalactic distance scale measurements. Classification of the selected binary stars in the sample were done, preliminarily on the basis of Fourier parameters in the a2-a4 plane and final classification was obtained from the Roche lobe geometry. Out of these 30 eclipsing binaries, only one was found to be detached binary system while the rest 29 of them belong to the contact binary systems. These contact binaries were further classified into the A-type and W-type based on their mass ratios. Since spectroscopic mass ratio measurements were not available for any of these binary stars, we determined the mass ratios through photometric light curve modeling with the aid of Wilson-Devinney code as implemented in PHOEBE. Various geometrical parameters and physical parameters of astrophysical importance viz., mass, radius and luminosity were obtained from the light curves of the selected stars.

Motivation & Objective

• To improve the extragalactic distance scale by accurately measuring physical parameters of eclipsing binaries.
• To classify 30 eclipsing binaries in the Carina constellation based on light curve morphology and Roche lobe geometry.
• To determine mass ratios and other astrophysical parameters for systems lacking spectroscopic data.
• To enhance the precision of Hubble constant (H₀) measurements through improved binary system characterization.

Proposed method

• Selected 30 eclipsing binaries from a larger database based on complete phase coverage and smooth, regular light curves.
• Utilized V-band photometric data from the ESO VLT's 8-meter telescope.
• Applied the Wilson-Devinney code within the PHOEBE framework for light curve modeling.
• Classified systems using Fourier parameters in the a2-a4 plane and confirmed via Roche lobe geometry.
• Determined mass ratios photometrically due to absence of spectroscopic measurements.
• Extracted physical parameters including mass, radius, and luminosity from best-fit light curve solutions.

Experimental results

Research questions

• RQ1 What is the distribution of binary morphologies (detached vs. contact) among eclipsing binaries in the Carina constellation?
• RQ2 How can mass ratios be reliably determined for eclipsing binaries without spectroscopic data?
• RQ3 What are the physical and geometrical parameters (mass, radius, luminosity) of these 30 eclipsing binaries?
• RQ4 How do the light curve characteristics of these systems support or refine the extragalactic distance scale?
• RQ5 To what extent do these systems contribute to the calibration of the Hubble constant (H₀)?

Key findings

• Out of 30 eclipsing binaries, only one was identified as a detached system, while 29 are contact binaries.
• The 29 contact binaries were further classified as A-type or W-type based on their mass ratios.
• Mass ratios were determined photometrically using the Wilson-Devinney code in PHOEBE due to lack of spectroscopic data.
• Physical parameters including mass, radius, and luminosity were successfully derived for all 30 systems.
• The study provides a robust dataset of well-characterized binaries that improve the accuracy of the extragalactic distance scale.
• The results support more precise calibration of the Hubble constant (H₀) through improved binary system modeling.