On the Spectroscopic Properties of the Retired A Star HD 185351

TL;DR

This study confirms that the subgiant star HD 185351 is a retired A star with a mass exceeding 1.6 solar masses, supporting the correlation between stellar mass and planet occurrence.

Contribution

The paper provides precise spectroscopic and asteroseismic measurements to independently confirm the high mass of HD 185351, a key example in stellar mass and planet occurrence studies.

Findings

HD 185351 has a mass of approximately 1.7 M_sun.

Spectroscopic analysis supports its classification as a retired A star.

Independent mass estimates agree with previous measurements.

Abstract

Doppler-based planet surveys have shown that, besides metallicity, the planet occurrence is also correlated with stellar mass, increasing from M to F-A spectral types. However, it has recently been argued that the subgiants (which represent A stars after they evolve off the main sequence) may not be as massive as suggested initially, which would significantly change the correlation found. To start investigating this claim, we have studied the subgiant star HD 185351, which has precisely measured physical properties based on asteroseismology and interferometry. An independent spectroscopic differential analysis based on excitation and ionization balance of iron lines yielded the atmospheric parameters $T_{\rm eff}$ = 5035 $\pm$ 29 K, $\log$ g = 3.30 $\pm$ 0.08 and [Fe/H] = 0.10 $\pm$ 0.04. These were used in conjunction with the PARSEC stellar evolutionary tracks to infer a mass M = 1.77 $\pm$ 0.04 M$_{\odot}$, which agrees well with the previous estimates. Lithium abundance was also estimated from spectral synthesis (A(Li) = 0.77 $\pm$ 0.07) and, together with $T_{\rm eff}$ and [Fe/H], allowed to determine a mass M = 1.64 $\pm$ 0.06 M$_{\odot}$, which is independent of the star's parallax and surface gravity. Our new measurements of the stellar mass support the notion that HD185351 is a Retired A Star with a mass in excess of 1.6 M$_{\odot}$.