BD+44 493: Chemo-Dynamical Analysis and Constraints on Companion Planetary Masses from WIYN/NEID Spectroscopy

TL;DR

This study provides a detailed chemo-dynamical analysis of the metal-poor star BD+44 493, constrains its planetary companions, and offers insights into early Universe star formation and Milky Way history.

Contribution

It presents high-resolution spectroscopic data and chemical abundance analysis of BD+44 493, constrains planetary masses around it, and links stellar archaeology with exoplanet science.

Findings

BD+44 493 is a low-mass, old second-generation star.

No planets larger than 2MJ within 100 days orbit.

Star likely formed from gas enriched by a single Population III star.

Abstract

In this work, we present high-resolution (R~100,000), high signal-to-noise (S/N~800) spectroscopic observations for the well-known, bright, extremely metal-poor, carbon-enhanced star BD+44 493. We determined chemical abundances and upper limits for 17 elements from WIYN/NEID data, complemented with 11 abundances re-determined from Subaru and Hubble data, using the new, more accurate, stellar atmospheric parameters calculated in this work. Our analysis suggests that BD+44 493 is a low-mass (0.83Msun) old (12.1-13.2Gyr) second-generation star likely formed from a gas cloud enriched by a single metal-free 20.5Msun Population III star in the early Universe. With a disk-like orbit, BD+44 493 does not appear to be associated with any major merger event in the early history of the Milky Way. From the precision radial-velocity NEID measurements (median absolute deviation - MAD=16m/s), we were able to constrain companion planetary masses around BD+44 493 and rule out the presence of planets as small as msin(i)=2MJ out to periods of 100 days. This study opens a new avenue of exploration for the intersection between stellar archaeology and exoplanet science using NEID.