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

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 M . 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.

The CHARA Array Interferometric Program on the Multiplicity of Classical Be Stars: New Detections and Orbits of Stripped Subdwarf Companions

“…V1294 Aql (HD 184279, HIP 96196) was recently reported as an SB1 binary with a low-mass companion (Harmanec et al 2022). This Be star was included in our sample at the end of the CHARA observing campaign, despite its distance being ∼1.4 kpc, which means that the angular resolution of our data might be too low to resolve the two components if the size of the orbit is at the lower end of the typical interval for close Be binaries.…”

The Orbital and Physical Properties of Five Southern Be+sdO Binary Systems

“…Recently, Nazé et al (2022) conducted a radial velocity (RV) monitoring survey for 16 γ Cas-type stars with strong X-ray emission, and they reported that these systems likely harbor a small mass companion (0.6-1.0  N  ) in orbits with long periods (80-120 days). Harmanec et al (2022) performed a comprehensive study to investigate the spectral, photometric, and color variations of V1294 Aql using observations spanning about 70 yr, and they concluded that this is likely another Be+sdO binary candidate system. An extensive analysis of archival optical spectra and new CHARA Array interferometry of κ Dra by Klement et al (2022a) suggest the existence of a cooler subdwarf companion (sdB) in this Be binary.…”