ItemArticle

The birth of Be star disks: I. from localized ejection to circularization

Title
The birth of Be star disks: I. from localized ejection to circularization
Creator
Labadie-Bartz, J.; Carciofi, A.C.; Rubio, A.C.; Baade, D.; Siverd, R.; Arcos, C.; Figueiredo, A.L.; Naz Y.; Neiner, C.; Rivinius, T.; Richardson, N.D.; Nova, S.; Pinho, M.L.; Bhattacharyya, S.; Leadbeater, R.; Guarro Fl J.; Lecocq, V.; Piehler, G.; Kozok, J.; Sollecchia, U.; Bryssinck, E.; Buil, C.; Martin, J.; Desnoux, V.; Heathcote, B.; Cacella, P.; Bertrand, G.; Broussat, J.J.; Ventura, A.; Diz, R.; Blais, A.; Somogyi, P.; Thizy, O.; Garde, O.; Charbonnel, S.; Le D P.; Mulato, L.; Petit, T.
Description
Context. Classical Be stars are well known to eject mass to build up a disk, but the details governing the initial distribution and subsequent evolution of this matter into a disk are in general poorly constrained through observations. Aims. By combining high-cadence time-series spectroscopy with contemporaneous space photometry from the Transiting Exoplanet Survey Satellite (TESS), we have sampled about 30 mass ejection events in 13 Be stars. Our goal is to constrain the geometrical and kinematic properties of the ejecta as early as possible, facilitating the investigation into the material's initial conditions and evolution, and understanding its interactions with preexisting material. Methods. The photometric variability is analyzed together with measurements of the at-times rapidly changing emission features in order to identify the onset of outburst events and obtain information about the geometry of the ejecta and how it changes over time. Short-lived line asymmetries display oscillation cycles (tefl frequencies), which are compared to photometric and stable spectroscopic frequencies. Results. All Be stars observed with sufficiently high cadence during an outburst are found to exhibit rapid oscillations of line asymmetry with a single frequency in the days following the start of the event. For a given star this circumstellar frequency may differ only slightly from event to event even when the outbursts they are associated with have different properties. These circumstellar frequencies are typically between 0.5 to 2 d- 1, and are generally near photometric frequencies. They are slightly below prominent (generally stable) spectroscopic frequencies seen in photospheric absorption lines. The emission asymmetry cycles break down after roughly 5- 10 cycles, with the emission line profile converging toward approximate symmetry shortly thereafter. In photometry, several frequencies typically emerge at relatively high amplitude at some point during the mass ejection process. Conclusions. In all observed cases, freshly ejected material was initially constrained within a narrow azimuthal range, indicating it was launched from a localized region on the stellar surface. The material orbits the star with a frequency consistent with the near-surface Keplerian orbital frequency. This material circularizes into a disk configuration after several orbital timescales. This is true whether or not there was a preexisting disk at the time of the observed outburst. We find no evidence for precursor phases prior to the ejection of mass in our sample. The several photometric frequencies that emerge during outburst are at least partially stellar in origin. The Authors 2025.
Source
Astronomy and Astrophysics;Volume;699;Issue;;Article No.;A82;
Date
01-01-2025
Publisher
EDP Sciences
Subject
Circumstellar matter; Stars: emission-line, Be; Stars: oscillations; Stars: winds, outflows; Techniques: photometric; Techniques: spectroscopic
Coverage
Labadie-Bartz J., LIRA, Observatoire de Paris, UniversitPSL, CNRS, Sorbonne Universit UniversitParis Cit CY Cergy Paris Universit Meudon, 92190, France; Carciofi A.C., Instituto de Astronomia, Geofica e Cicias Atmosficas, Universidade de S Paulo, Rua do Mat 1226, Cidade Universitia, SP, S Paulo, B-05508-900, Brazil; Rubio A.C., Instituto de Astronomia, Geofica e Cicias Atmosficas, Universidade de S Paulo, Rua do Mat 1226, Cidade Universitia, SP, S Paulo, B-05508-900, Brazil, Max-Planck-Institut f Astrophysik, Karl-Schwarzschild-Str. 1, Garching b. Mchen, 85748, Germany; Baade D., European Organisation for Astronomical Research in the Southern Hemisphere (ESO), Karl-Schwarzschild-Str. 2, Garching b. Mchen, 85748, Germany; Siverd R., Institute for Astronomy, University of Hawaii, 2680 Woodlawn, Honolulu, 96822, HI, United States; Arcos C., Instituto de Fica y Astronom, Facultad de Ciencias, Universidad de Valparao, Av. Gran Bretana 1111, Valparao, Chile; Figueiredo A.L., Instituto de Astronomia, Geofica e Cicias Atmosficas, Universidade de S Paulo, Rua do Mat 1226, Cidade Universitia, SP, S Paulo, B-05508-900, Brazil; NazY., Groupe d'Astrophysique des Hautes Energies, STAR, Universite de Liege, Quartier Agora (B5c, Institut d'Astrophysique et de Geophysique), All du 6 Ao 19c, Sart Tilman, Lie, 4000, Belgium; Neiner C., LIRA, Observatoire de Paris, UniversitPSL, CNRS, Sorbonne Universit UniversitParis Cit CY Cergy Paris Universit Meudon, 92190, France; Rivinius T., European Organisation for Astronomical Research in the Southern Hemisphere (ESO), Casilla 19001, Santiago, 19, Chile; Richardson N.D., Department of Physics and Astronomy, Embry-Riddle Aeronautical University, 3700 Willow Creek Rd, Prescott, 86301, AZ, United States; Nova S., Department of Physics and Astronomy, Embry-Riddle Aeronautical University, 3700 Willow Creek Rd, Prescott, 86301, AZ, United States; Pinho M.L., Instituto de Astronomia, Geofica e Cicias Atmosficas, Universidade de S Paulo, Rua do Mat 1226, Cidade Universitia, SP, S Paulo, B-05508-900, Brazil; Bhattacharyya S., European Organisation for Astronomical Research in the Southern Hemisphere (ESO), Casilla 19001, Santiago, 19, Chile, CHRIST (Deemed to Be University), Bangalore, India; Leadbeater R., Three Hills Observatory, The Birches, Torpenhow, CA7 1JF, United Kingdom, The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Guarro FlJ., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France, Piera Remote Observatory, C. de Jaume Balmes 2, Catalonia Piera, Barcelona, 08784, Spain, SMM Remote Observatory, Av. de Catalunya 38, Catalonia, Santa Maria de Montmagastrell (Trega), 25345, Spain; Lecocq V., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Piehler G., Selztal Observatory, Bechtolsheimer Weg 26, Friesenheim, 55278, Germany; Kozok J., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Sollecchia U., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Bryssinck E., BRIXIIS Observatory (MPC:B96), Kruibeke, Belgium; Buil C., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Martin J., Huggins Spectroscopic Observatory, Rayleigh, Essex, SS6 8AW, United Kingdom; Desnoux V., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Heathcote B., Glenpiper Observatory, 165 Sievers LaneGlenhope, 3444, VIC, Australia; Cacella P., DogsHeaven Observatory X87, Brasilia, Brazil; Bertrand G., La Montagne Observatory, 1 B Rue Jacques Prevert, La Montagne, 44620, France; Broussat J.J., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Ventura A., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Diz R., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Blais A., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Somogyi P., The Be Star Spectra (BeSS) Database Operated at LIRA, Observatoire de Paris, Meudon, France; Thizy O., Observatoire Belle Etoile, Revel, 38420, France; Garde O., 2SPOT, 45, Chemin du Lac, Chons, 38690, France; Charbonnel S., 2SPOT, 45, Chemin du Lac, Chons, 38690, France; Le DP., 2SPOT, 45, Chemin du Lac, Chons, 38690, France; Mulato L., 2SPOT, 45, Chemin du Lac, Chons, 38690, France; Petit T., 2SPOT, 45, Chemin du Lac, Chons, 38690, France
Rights
All Open Access; Gold Open Access; Green Open Access
Relation
ISSN: 46361; CODEN: AAEJA
Format
online
Language
English
Type
Article

Citation

Labadie-Bartz, J.; Carciofi, A.C.; Rubio, A.C.; Baade, D.; Siverd, R.; Arcos, C.; Figueiredo, A.L.; Naz Y.; Neiner, C.; Rivinius, T.; Richardson, N.D.; Nova, S.; Pinho, M.L.; Bhattacharyya, S.; Leadbeater, R.; Guarro Fl J.; Lecocq, V.; Piehler, G.; Kozok, J.; Sollecchia, U.; Bryssinck, E.; Buil, C.; Martin, J.; Desnoux, V.; Heathcote, B.; Cacella, P.; Bertrand, G.; Broussat, J.J.; Ventura, A.; Diz, R.; Blais, A.; Somogyi, P.; Thizy, O.; Garde, O.; Charbonnel, S.; Le D P.; Mulato, L.; Petit, T., “The birth of Be star disks: I. from localized ejection to circularization,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 18, 2026, https://archives.christuniversity.in/items/show/22611.

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