Spectroscopic orbit determination of the long-periodic binary system $\theta$ Cep

TL;DR

This paper presents a new, more accurate orbital solution for the long-period binary star $ heta$ Cep, based on extensive radial velocity data, revealing a longer period and higher eccentricity than previously recorded.

Contribution

It provides the first comprehensive orbital solution for $ heta$ Cep using homogeneous radial velocity data, updating its period and eccentricity.

Findings

Longer orbital period than previous estimates

Higher orbital eccentricity identified

Homogeneous radial velocity data enabled precise orbit determination

Abstract

In 2015 a radial velocity monitoring campaign was started in order to redetermine and/or constrain the orbital solutions of spectroscopic binary systems. The observations were carried out at the University Observatory Jena with the \'Echelle spectrograph FLECHAS. The results from the main part of our target sample are already published. For the final target of this campaign, $\theta$ Cep, we can now present an orbital solution based on a homogeneously covered radial velocity curve. The period of this single-lined spectroscopic binary turns out to be significantly larger and the orbit is much more eccentric compared to the given values in the 9th Catalogue of Spectroscopic Binary Orbits.