Non-Detection of the Putative Substellar Companion to HD 149382

TL;DR

This study conducted radial velocity measurements of HD 149382 to verify a claimed substellar companion and found no evidence supporting its existence, challenging previous claims and implications for stellar evolution.

Contribution

The paper provides the first high-precision radial velocity data that conclusively refutes the existence of the proposed substellar companion to HD 149382.

Findings

No substellar companion detected within 28 days period

Rules out companions with Msin i >~ 1 Mjup

Contradicts previous claims of a planetary companion

Abstract

It has been argued that a substellar companion may significantly influence the evolution of the progenitors of sdB stars. Recently, the bright sdB star HD 149382 has been claimed to host a substellar (possibly planetary) companion with a period of 2.391 days. This has important implications for the evolution of the progenitors of sdB stars as well as the source of the UV-excess seen in elliptical galaxies. In order to verify this putative planet, we made 10 radial velocity measurements of HD 149382 over 17 days with the High Resolution Spectrograph at the Hobby-Eberly Telescope. Our data conclusively demonstrate that the putative substellar companion does not exist, and they exclude the presence of almost any substellar companion with P < 28 days and Msin i >~ 1 Mjup.