KOI-126: A Triply-Eclipsing Hierarchical Triple with Two Low-Mass Stars

TL;DR

This paper reports the discovery of KOI-126, a unique triply-eclipsing hierarchical triple star system with two low-mass stars, providing valuable data for testing stellar models.

Contribution

It presents the first detailed characterization of a triply-eclipsing hierarchical triple system with low-mass stars, offering new benchmarks for stellar evolution theories.

Findings

Discovered KOI-126 as a triply-eclipsing system.

Measured precise masses and radii of low-mass stars.

Provided data to test models of fully-convective stars.

Abstract

The Kepler spacecraft has been monitoring the light from 150,000 stars in its primary quest to detect transiting exoplanets. Here we report on the detection of an eclipsing stellar hierarchical triple, identified in the Kepler photometry. KOI-126 (A,(B, C)), is composed of a low-mass binary (masses M_B = 0.2413+/-0.0030 M_Sun, M_C = 0.2127+/-0.0026 M_Sun; radii R_B = 0.2543+/-0.0014 R_Sun, R_C = 0.2318+/-0.0013 R_Sun; orbital period P_1 = 1.76713+/-0.00019 days) on an eccentric orbit about a third star (mass M_A = 1.347+/-0.032 M_Sun; radius R_A = 2.0254+/-0.0098 R_Sun; period of orbit around the low-mass binary P_2 = 33.9214+/-0.0013 days; eccentricity of that orbit e_2 = 0.3043+/-0.0024). The low-mass pair probe the poorly sampled fully-convective stellar domain offering a crucial benchmark for theoretical stellar models.