_version_ 1866908311428792320
author Labadie-Bartz, J.
Carciofi, A. C.
Rubio, A. C.
Baade, D.
Siverd, R.
Arcos, C.
Figueiredo, A. L.
Nazé, Y.
Neiner, C.
Rivinius, T.
Richardson, N. D.
Nova, S.
Pinho, M. L.
Bhattacharyya, S.
Leadbeater, R.
Fló, J. Guarro
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.
Dû, P. Le
Mulato, L.
Petit, T.
author_facet Labadie-Bartz, J.
Carciofi, A. C.
Rubio, A. C.
Baade, D.
Siverd, R.
Arcos, C.
Figueiredo, A. L.
Nazé, Y.
Neiner, C.
Rivinius, T.
Richardson, N. D.
Nova, S.
Pinho, M. L.
Bhattacharyya, S.
Leadbeater, R.
Fló, J. Guarro
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.
Dû, P. Le
Mulato, L.
Petit, T.
contents Classical Be stars are well known to eject mass, but the details governing the initial distribution and evolution of this matter into a disk are poorly constrained by observations. By combining high-cadence spectroscopy with contemporaneous space photometry from 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, facilitating the investigation into the initial conditions and evolution, and understanding its interactions with preexisting material. The photometric variability is analyzed together with measurements of the rapidly changing emission features to identify the onset of outburst events and obtain information about the geometry of the ejecta and its evolution. All Be stars observed with sufficiently high cadence exhibit rapid oscillations of line asymmetry with a single frequency in the days following the start of the event. The emission asymmetry cycles break down after roughly 5 - 10 cycles, with the emission line profile converging toward approximate symmetry. In photometry, several frequencies typically emerge at relatively high amplitude at some point during the mass ejection process. In all observed cases, freshly ejected material was initially within a narrow azimuthal range, indicating it was launched from a localized region on the star. 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. 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. (Abstract abridged)
format Preprint
id arxiv_https___arxiv_org_abs_2504_07571
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The birth of Be star disks I. From localized ejection to circularization
Labadie-Bartz, J.
Carciofi, A. C.
Rubio, A. C.
Baade, D.
Siverd, R.
Arcos, C.
Figueiredo, A. L.
Nazé, Y.
Neiner, C.
Rivinius, T.
Richardson, N. D.
Nova, S.
Pinho, M. L.
Bhattacharyya, S.
Leadbeater, R.
Fló, J. Guarro
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.
Dû, P. Le
Mulato, L.
Petit, T.
Solar and Stellar Astrophysics
Classical Be stars are well known to eject mass, but the details governing the initial distribution and evolution of this matter into a disk are poorly constrained by observations. By combining high-cadence spectroscopy with contemporaneous space photometry from 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, facilitating the investigation into the initial conditions and evolution, and understanding its interactions with preexisting material. The photometric variability is analyzed together with measurements of the rapidly changing emission features to identify the onset of outburst events and obtain information about the geometry of the ejecta and its evolution. All Be stars observed with sufficiently high cadence exhibit rapid oscillations of line asymmetry with a single frequency in the days following the start of the event. The emission asymmetry cycles break down after roughly 5 - 10 cycles, with the emission line profile converging toward approximate symmetry. In photometry, several frequencies typically emerge at relatively high amplitude at some point during the mass ejection process. In all observed cases, freshly ejected material was initially within a narrow azimuthal range, indicating it was launched from a localized region on the star. 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. 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. (Abstract abridged)
title The birth of Be star disks I. From localized ejection to circularization
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2504.07571