Stellar parameters for the central star of the planetary nebula PRTM 1 using the German Astrophysical Virtual Observatory service TheoSSA

TL;DR

This paper demonstrates how the German Virtual Observatory service TheoSSA can be used to analyze the stellar parameters of the central star of PRTM 1, utilizing NLTE stellar atmosphere models to derive temperature, gravity, composition, mass, and luminosity.

Contribution

It introduces the use of TheoSSA for detailed spectral analysis of hot stars, enabling easy access to pre-calculated spectra and custom model calculations.

Findings

Measured stellar temperature of 98,000 K with 5,000 K uncertainty.

Derived stellar mass of approximately 0.73 solar masses.

Determined photospheric abundances and luminosity of the star.

Abstract

The German Astrophysical Virtual Observatory (GAVO) developed the registered service TheoSSA (theoretical stellar spectra access) and the supporting registered VO tool TMAW (Tuebingen Model-Atmosphere WWW interface). These allow individual spectral analyses of hot, compact stars with state-of-the-art non-local thermodynamical equilibrium (NLTE) stellar-atmosphere models that presently consider opacities of the elements H, He, C, N, O, Ne, Na, and Mg, without requiring detailed knowledge about the involved background codes and procedures. Presently, TheoSSA provides easy access to about 150000 pre-calculated stellar SEDs and is intended to ingest SEDs calculated by any model-atmosphere code. In the case of the exciting star of PRTM 1, we demonstrate the easy way to calculate individual NLTE stellar model-atmospheres to reproduce an observed optical spectrum. We measured Teff = 98000 +/- 5000 K, log (g / cm/s**2) = 5.0 (+0.3/-0.2) and photospheric mass fractions of H = 7.5 x 10**-1 (1.02 times solar), He = 2.4 x 10**-1 (0.96), C = 2.0 x 10**-3 (0.84), N = 3.2 x 10**-4 (0.46), O = 8.5 x 10**-3 (1.48) with uncertainties of +/- 0.2 dex. We determined the stellar mass and luminosity of 0.73 (+0.16/-0.15) Msun and log (L / Lsun) = 4.2 +/- 0.4, respectively.