| Name: Suman Bhattacharyya |
| Affiliation: CHRIST (Deemed to be University), Bangalore |
| Conference ID: ASI2026_221 |
| Title: The Imposter in the BeXRB Catalog: Reassessing the Nature of HD 249179 |
| Abstract Type: Poster |
| Abstract Category: Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Author(s) and Co-Author(s) with Affiliation: Suman Bhattacharyya(CHRIST (Deemed to be University), Bangalore, India), Blesson Mathew(CHRIST (Deemed to be University), Bangalore, India), Sreeja S Kartha(CHRIST (Deemed to be University), Bangalore, India), Muneer S(Indian Institute of Astrophysics, Bangalore - 560034, India) |
| Abstract: The B-type star HD 249179 presents a long standing classification ambiguity, historically oscillating between a classical Be star and a candidate High-Mass X-Ray Binary (HMXB). Resolving this nature is critical for understanding the population of "quiet" HMXBs versus isolated active Be stars. In this work, we present a comprehensive long-term spectro-photometric analysis of HD 249179, combining optical spectroscopy (LAMOST, BeSS, HCT) with high-cadence space-based photometry (TESS) and long-baseline ground-based monitoring (AAVSO, ASAS-SN) spanning 2017–2023. Our analysis of the H-alpha emission line reveals a highly dynamic circumstellar environment, characterized by a rapid disk dissipation and recovery event on timescales of days in 2017—faster than typical viscous diffusion timescales, followed by a steady re-growth phase leading to a stable, dense decretion disk by 2022. TESS photometry unveils high-frequency pulsations characteristic of early Be stars, alongside a distinct brightening event associated with a mass-ejection episode. Furthermore, we detect weak asymmetries in the emission profiles indicative of spiral density waves or global disk oscillations (V/R variations). Crucially, despite historical catalog associations, our multi-epoch study finds no evidence of accretion-driven X-ray emission. We argue that HD 249179 is a classical Be star exhibiting rapid disk cycles driven by pulsation-aided mass loss, rather than binary interaction. This study provides strict constraints on the object's re-classification and offers new insights into the timescales of disk formation in isolated B-type stars. |
