Photometry and spectrophotometry of the Herbig Ae star RR Tauri

TL;DR

This study presents multicolour photometry and spectroscopy of RR Tauri, revealing a grey spectral continuum during deep fading, changes in emission flux, and insights into its circumstellar environment and evolutionary status.

Contribution

It provides detailed observational analysis of RR Tauri's variability, including spectral and photometric changes, and refines its classification and evolutionary stage.

Findings

Star experienced over 10-fold flux decrease during fade

Spectral continuum remained grey despite fading

Circumstellar reddening consistent with Rv=5, spectral type near A0

Abstract

Multicolour broadband photometry and flux calibrated low resolution spectroscopy between 2014 and 2018 are used to investigate the behaviour of the highly variable Herbig Ae star RR Tauri. As the star experienced a deep Algol-like fade by a factor of over 10 in flux, we found the change in spectral continuum to be grey while H{\alpha} emission flux halved. We also observed the (V-Rc) colour index reddening as the star faded suggesting emission detectable in the Rc-band but beyond our spectral response. We confirm that the circumstellar reddening of RR Tau is consistent with an extinction ratio Rv = 5 and that its spectral type is close to A0. According to its luminosity and temperature RR Tau is located in the H-R diagram among other HAEBE stars contracting onto the Zero Age Main Sequence and has a mass between 4 and 5 MSun.