Discovery of Par 1802 as a Low-Mass, Pre-Main-Sequence Eclipsing Binary in the Orion Star-Forming Region

TL;DR

This paper reports the discovery and characterization of Par 1802, a low-mass, pre-main-sequence eclipsing binary in Orion, providing valuable empirical data to test stellar evolution models for young, low-mass stars.

Contribution

It presents the first detailed orbital and mass measurements of Par 1802, a young low-mass binary in Orion, aiding the calibration of pre-main-sequence stellar models.

Findings

Par 1802 consists of two equal-mass stars (~0.4 Msun) in a 4.7-day orbit.

The system shows strong lithium lines, indicating youth.

The system's properties are consistent with membership in the Orion star-forming region.

Abstract

We report the discovery of a pre-main-sequence, low-mass, double-lined, spectroscopic, eclipsing binary in the Orion star-forming region. We present our observations including radial velocities derived from optical high-resolution spectroscopy, and present an orbit solution that permits the determination of precise empirical masses for both components of the system. We measure that Par 1802 is composed of two equal mass (0.39+-0.03, 0.40+-0.03 Msun) stars in a circular, 4.7 day orbit. There is strong evidence, such as the system exhibiting strong Li lines and a center-of-mass velocity consistent with cluster membership, that this system is a member of the Orion star-forming region and quite possibly the Orion Nebula Cluster, and therefore has an age of only a few million years. As there are currently only a few empirical mass and radius measurements for low-mass, PMS stars, this system presents an interesting test for the predictions of current theoretical models of pre-main sequence stellar evolution.