Detection of the Binarity of the Star J1158+4239

TL;DR

This study confirms the binarity of star J1158+4239 using speckle observations, providing precise measurements of its binary parameters and demonstrating the effectiveness of the observational program for low-luminosity stars.

Contribution

The paper reports the first confirmation and detailed parameter determination of the binary nature of J1158+4239 through speckle interferometry, advancing methods for studying low-luminosity stellar binaries.

Findings

Binarity of J1158+4239 confirmed.

Measured binary separation and position angle.

Estimated magnitude difference between binary components.

Abstract

One of the goals of the Pulkovo program of research on stars with large proper motions is to reveal among the low-luminosity stars those that have evidence of binarity. Twelve astrometric binary candidates from the Pulkovo list have been included in the program of speckle observations with the BTA telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) and the 2.5-m telescope at the Caucasus Mountain Observatory (CMO) of the Sternberg Astronomical Institute of the Moscow State University to confirm their binarity and then to determine the parameters of the revealed stellar pairs. The binarity of the brightest of these stars, J1158+4239 (GJ 3697), has been confirmed. Four sessions of speckle observations with the BTA SAO RAS telescope and one session with the 2.5-m CMO telescope have been carried out in 2015 - 2016. The weighted mean estimates of the pair parameters are $\rho$=286.5$\pm$1.2 mas and $\theta$=230.24$\pm$0.16$^{\circ}$ at the epoch B2015.88248. The magnitude difference between the pair stars is $\Delta m$=0.55$\pm$0.03 (a filter with a central wavelength of 800 nm and a FWHM of 100 nm) and $\Delta m$=0.9$\pm$0.1 (an R filter).