Spectroscopic analysis of the B/Be visual binary HR 1847

TL;DR

This study spectroscopically analyzed the binary HR 1847, determining its orbital parameters and confirming the Be star nature of its secondary component, with new spectroscopic orbit data for the primary.

Contribution

First spectroscopic orbit of HR 1847A established, revealing a highly eccentric orbit and detailed physical parameters of both binary components.

Findings

HR 1847A is a single-lined binary with a 719.79-day period.

HR 1847B is confirmed as a Be star with variable Hα emission.

Both stars are B7-8 type, luminosity class IV-V.

Abstract

We studied both components of a slightly overlooked visual binary HR 1847 spectroscopically to determine its basic physical and orbital parameters. Basic stellar parameters were determined by comparing synthetic spectra to the observed echelle spectra, which cover both the optical and near-IR regions. New observations of this system used the Ond\v{r}ejov and Rozhen 2-m telescopes and their coud\'e spectrographs. Radial velocities from individual spectra were measured and then analysed with the code {\FOTEL} to determine orbital parameters. The spectroscopic orbit of HR 1847A is presented for the first time. It is a single-lined spectroscopic binary with a B-type primary, a period of 719.79 days, and a highly eccentric orbit with e=0.7. We confirmed that HR 1847B is a Be star. Its H\alpha emission significantly decreased from 2003 to 2008. Both components have a spectral type B7-8 and luminosity class IV-V.