The Radio Continuum Source Projected Near HR 8799

TL;DR

This study reports the detection of a faint radio source near HR 8799, but astrometric analysis indicates it is a background galaxy, not associated with the star or its exoplanets.

Contribution

The paper presents the first VLA detection of a radio source near HR 8799 and demonstrates it is a background galaxy through astrometric analysis.

Findings

Detected a faint radio source near HR 8799 at 3.0 GHz.

Astrometry shows the source is a background galaxy, not associated with HR 8799.

The source exhibits dust emission and synchrotron radiation characteristics.

Abstract

HR 8799 is an A5/F0 V star where exoplanets were first directly imaged. Four exoplanets were found within $\simeq 2\rlap.{''}0$ from the star. Here we report the VLA detection of a faint (19.1$\pm$2.7 $\mu$Jy) radio continuum (3.0 GHz) source projected at $\simeq 2\rlap.{''}2$ from the star. The \sl a priori \rm probability of finding a background source with this flux density within a radius of $2\rlap.{''}2$ is only 0.0046. However, the astrometry made with the VLA and ALMA images, separated by 5.5 years, indicates no significant proper motions and rules out the association of the radio source with the HR 8799 system and suggests it is a background millimeter galaxy with dust emission in the millimeter and partially thick synchrotron emission in the centimeter.