TESS Discovery of Twin Planets near 2:1 Resonance around Early M-Dwarf TOI 4342

TL;DR

This paper reports the discovery and validation of a two-planet system near 2:1 resonance around an early M-dwarf using TESS data, showcasing improvements in the detection pipeline and highlighting the system's suitability for atmospheric studies.

Contribution

The paper introduces enhancements to the MIT Quick-Look Pipeline that enable more effective multi-planet detection using TESS data, leading to the discovery of a notable system around TOI 4342.

Findings

Discovered two sub-Neptunes near 2:1 resonance around TOI 4342.

Validated planets with ground-based follow-up observations.

System has high transmission spectroscopy metrics, ideal for atmospheric studies.

Abstract

With data from the Transiting Exoplanet Survey Satellite (TESS), we showcase improvements to the MIT Quick-Look Pipeline (QLP) through the discovery and validation of a multi-planet system around M-dwarf TOI 4342 ($T_{mag}=11.032$, $M_* = 0.63 M_\odot$, $R_* = 0.60 R_\odot$, $T_{eff} = 3900$ K, $d = 61.54$ pc). With updates to QLP, including a new multi-planet search, as well as faster cadence data from TESS' First Extended Mission, we discovered two sub-Neptunes ($R_b = 2.266_{-0.038}^{+0.038} R_\oplus$ and $R_c = 2.415_{-0.040}^{+0.043} R_\oplus$; $P_b$ = 5.538 days and $P_c$ = 10.689 days) and validated them with ground-based photometry, spectra, and speckle imaging. Both planets notably have high transmission spectroscopy metrics (TSMs) of 36 and 32, making TOI 4342 one of the best systems for comparative atmospheric studies. This system demonstrates how improvements to QLP, along with faster cadence Full-Frame Images (FFIs), can lead to the discovery of new multi-planet systems.