Standard stellar luminosities; what are typical and limiting accuracies in the era after Gaia?

TL;DR

This paper revises methods for determining stellar luminosities, introduces the concept of standard stellar luminosity, and compares the accuracy of three methods, highlighting the potential for sub-1% precision with spectral flux ratio techniques.

Contribution

It defines a new concept of standard stellar luminosity and evaluates the accuracy of different methods, emphasizing the superior potential of spectral flux ratio-based measurements.

Findings

Spectral flux ratio method can achieve ~1% accuracy in luminosity.

Secondary methods are less accurate than the direct spectral flux ratio method.

The direct method's typical accuracy ranges from 8.2% to 12.2%, with a limiting accuracy of 2.5%.

Abstract

Methods of obtaining stellar luminosities (L) have been revised and a new concept, standard stellar luminosity, has been defined. Among the three methods (direct method from radii and effective temperatures, method using a mass-luminosity relation (MLR), and method requiring a bolometric correction), the third method, which uses the unique bolometric correction (BC) of a star extracted from a flux ratio ($f_{\rm V}/f_{\rm Bol}$) obtained from the observed spectrum with sufficient spectral coverage and resolution, is estimated to provide an uncertainty ($\Delta L/L$) typically at a low percentage, which could be as accurate as 1% perhaps more. The typical and limiting uncertainties of the predicted L of the three methods were compared. The secondary methods requiring either a pre-determined non-unique BC or MLR were found to provide less accurate luminosities than the direct method, which could provide stellar luminosities with a typical accuracy of 8.2% - 12.2% while its estimated limiting accuracy is 2.5%.