Observations and light curve solutions of ultrashort-period eclipsing binaries

TL;DR

This study presents photometric and spectroscopic observations of ten ultrashort-period eclipsing binaries, revealing their configurations, stellar properties, and empirical relations, including the discovery of a new binary system.

Contribution

It provides detailed light curve solutions and analysis for ultrashort-period binaries, including a newly discovered system, and establishes empirical relations for their stellar parameters.

Findings

Eight targets are overcontact binaries with significant fillout factors.

NSVS 4876238 is a rare detached ultrashort-period binary.

Linear relations between mass, luminosity, and radius were derived.

Abstract

Photometric observations in V and I bands and low-dispersion spectra of ten ultrashort-period binaries (NSVS 2175434, NSVS 2607629, NSVS 5038135, NSVS 8040227, NSVS 9747584, NSVS 4876238, ASAS 071829-0336.7, SWASP 074658.62+224448.5, NSVS 2729229, NSVS 10632802) are presented. One of them, NSVS 2729229, is newly discovered target. The results from modeling and analysis of our observations revealed that: (i) Eight targets have overcontact configurations with considerable fillout factor (up to 0.5) while NSVS 4876238 and ASAS 0718-03 have almost contact configurations; (ii) NSVS 4876238 is rare ultrashort-period binary of detached type; (iii) all stellar components are late dwarfs; (iv) the temperature difference of the components of each target does not exceed 400 K; (v) NSVS 2175434 and SWASP 074658.62+224448.5 exhibit total eclipses and their parameters could be assumed as well-determined; (v) NSVS 2729229 shows emission in the H_{alpha} line. Masses, radii and luminosities of the stellar components were estimated by the empirical relation "period, orbital axis" for short- and ultrashort-period binaries. We found linear relations mass-luminosity and mass-radius for the stellar components of our targets.