Validation of HD 183579b using archival radial velocities: a warm-neptune orbiting a bright solar analog

TL;DR

This study validates the existence of a warm-Neptune exoplanet, HD 183579b, using archival radial velocity data, demonstrating that existing observations can confirm and characterize new transiting planets from TESS without additional data collection.

Contribution

It presents the validation of HD 183579b through archival RV data, showcasing the potential of existing datasets to confirm and measure properties of TESS planet candidates.

Findings

HD 183579b is a validated warm-Neptune orbiting a bright solar analog.

The planet has a radius less than 4 Earth radii and a mass measurement with over 33% accuracy.

Archival data can be effectively used to confirm and characterize transiting exoplanets.

Abstract

As exoplanetary science matures into its third decade, we are increasingly offered the possibility of pre existing, archival observations for newly detected candidates. This is particularly poignant for the TESS mission, whose survey spans bright, nearby dwarf stars in both hemispheres, which are precisely the types of sources targeted by previous radial velocity (RV) surveys. On this basis, we investigated whether any of the TESS Objects of Interest (TOIs) coincided with such observations, from which we find 18 single planet candidate systems. Of these, one exhibits an RV signature that has the correct period and phase matching the transiting planetary candidate with a false alarm probability of less than 1 percent. After further checks, we exploit this fact to validate HD 183579b (TOI-1055b). This planet is less than 4 Earth Radii and has better than 33 percent planetary mass measurements, thus advancing the TESS primary objective of finding 50 such worlds. We find that this planet is amongst the most accessible small transiting planets for atmospheric characterization. Our work highlights that the efforts to confirm and even precisely measure the masses of new transiting planet candidates need not always depend on acquiring new observations - that in some instances these tasks can be completed with existing data.