NSV 11154 Is a New R Coronae Borealis Star

TL;DR

NSV 11154 is confirmed as a new R Coronae Borealis star exhibiting characteristic irregular declines, spectral features, and infrared excess, with its unique galactic position providing insights into RCB star populations.

Contribution

This paper confirms NSV 11154 as a new RCB star using photometric and spectroscopic data, and analyzes its properties and galactic location.

Findings

NSV 11154 shows typical RCB star lightcurve declines.

Spectroscopy confirms its hydrogen deficiency and carbon-rich nature.

Infrared excess indicates circumstellar dust at ~800 K.

Abstract

NSV 11154 has been confirmed as a new member of the rare hydrogen deficient R Coronae Borealis (RCB) stars based on new photometric and spectroscopic data. Using new photometry, as well as archival plates from the Harvard archive, we have constructed the historical lightcurve of NSV 11154 from 1896 to the present. The lightcurve shows the sudden, deep, irregularly spaced declines characteristic of RCB stars. The visible spectrum is typical of a cool (Teff < 5000 K) RCB star showing no hydrogen lines, strong C2 Swan bands, and no evidence of 13C. In addition, the star shows small pulsations typical of an RCB star, and an infrared excess due to circumstellar dust with a temperature of ~800 K. The distance to NSV 11154 is estimated to be ~14.5 kpc. RCB stars are very rare in the Galaxy so each additional star is important to population studies leading to a better understanding the origins of these mysterious stars. Among the known sample of RCB stars, NSV 11154 is unusual in that it lies well above the Galactic plane (5 kpc) and away from the Galactic Center which suggests that its parent population is neither thick disk nor bulge.