Infrared excesses in stars with and without planets using revised ${\it WISE}$ photometry

TL;DR

This study investigates the occurrence of mid-infrared excesses in stars with and without planets using revised WISE data, finding very low and comparable excess detection rates in both groups, and suggests a calibration revision for WISE fluxes.

Contribution

It provides a revised analysis of infrared excess prevalence in stars with and without planets using updated WISE photometry and highlights the need for calibration adjustments.

Findings

Detection rate of 0.85% in stars with planets

Detection rate of 0.1% in stars without planets

No significant difference between the two groups

Abstract

We present an analysis on the potential prevalence of mid infrared excesses in stars with and without planetary companions. Based on an extended database of stars detected with the ${\it WISE}$ satellite, we studied two stellar samples: one with 236 planet hosts and another with 986 objects for which planets have been searched but not found. We determined the presence of an excess over the photosphere by comparing the observed flux ratio at 22 $\mu$m and 12 $\mu$m ($f_{22}/f_{12}$) with the corresponding synthetic value, derived from results of classical model photospheres. We found a detection rate of 0.85$\%$ at 22 $\mu$m (2 excesses) in the sample of stars with planets and 0.1$\%$ (1 detection) for the stars without planets. The difference of the detection rate between the two samples is not statistically significant, a result that is independent of the different approaches found in the literature to define an excess in the wavelength range covered by ${\it WISE}$ observations. As an additional result, we found that the ${\it WISE}$ fluxes required a normalisation procedure to make them compatible with synthetic data, probably pointing out a revision of the ${\it WISE}$ data calibration.