V1294 Aql = HD 184279: A bad boy among Be stars or an important clue to the Be phenomenon?

TL;DR

This study thoroughly analyzes V1294 Aql, revealing its binary nature, complex variability, and potential implications for understanding the Be phenomenon and stellar evolution.

Contribution

It provides the first detailed long-term spectroscopic and photometric analysis of V1294 Aql, identifying it as a binary with intricate variability patterns.

Findings

V1294 Aql is a single-line 192.9-day spectroscopic binary.

The secondary is likely a hot compact object of about 1.1-1.2 solar masses.

The star exhibits complex spectral, light, and color variations.

Abstract

A reliable determination of the basic physical properties and variability patterns of hot emission-line stars is important for understanding the Be phenomenon and ultimately, the evolutionary stage of Be stars. This study is devoted to one of the most remarkable Be stars, V1294 Aql = HD 184279. We collected and analysed spectroscopic and photometric observations covering a time interval of about 25000 d (68 yr). We present evidence that the object is a single-line 192.9 d spectroscopic binary and estimate that the secondary probably is a hot compact object with a mass of about 1.1-1.2 solar masses. We found and documented very complicated orbital and long-term spectral, light, and colour variations, which must arise from a combination of several distinct variability patterns. Attempts at modelling them are planned for a follow-up study. We place the time behaviour of V1294 Aql into context with variations known for some other systematically studied Be stars and discuss the current ideas about the nature of the Be phenomenon.