J/ApJ/928/145ivo://CDS.VizieR/J/ApJ/928/145doi:10.26093/cds/vizier.19280145CDSMarr K.C.Jones C.E.Tycner C.Carciofi A.C.Silva A.C.F.2024-11-06T20:24:19Z2024-03-19T12:56:24ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frbe-starsvisible-astronomyspectroscopyWe acquired H{alpha} spectroscopic observations from 2005 to 2019 showing Pleione has transitioned from a Be phase to a Be-shell phase during this period. Using the radiative transfer code hdust, we created a grid of ~100,000 disk models for Pleione. We successfully reproduced the observed transition with a disk model that varies in inclination while maintaining an equatorial density of {rho}_0_(r)=3x10^-11^(r/R_eq_)^-2.7^g/cm^3^, and an H{alpha}-emitting region extending to 15R_eq_. We use a precessing disk model to extrapolate the changing disk inclination over 120 yr and follow the variability in archival observations. The best-fit disk model precesses over a line-of-sight inclination between ~25{deg} and ~144{deg} with a precessional period of ~80.5yr. Our precessing models match some of the observed variability but fail to reproduce all of the historical data available. Therefore, we propose an ad hoc model based on our precessing disk model inspired by recent smoothed particle hydrodynamics simulations of similar systems, where the disk tears due to the tidal influence of a companion star. In this model, a single disk is slowly tilted to an angle of 30{deg} from the stellar equator over 34yr. Then, the disk is torn by the companion's tidal torque, with the outer region separating from the innermost disk. The small inner disk returns to the stellar equator as mass injection remains constant. The outer disk precesses for ~15yr before gradually dissipating. The process repeats every 34yr and reproduces all trends in Pleione's variability.2022ApJ...928..145Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/928/145CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/A+A/440/305 : Fundamental param. of fast-rotating B stars (Fremat+, 2005)J/ApJS/172/663 : Infrared observations of the Pleiades (Stauffer+, 2007)J/AJ/143/28 : Analysis of B6-A9 stars from INES UV spectra (Freire+, 2012)J/A+A/553/A24 : Models for rotating stars (Georgy+, 2013)J/ApJ/768/128 : K-band calibrated visibilities of 24 Be stars (Touhami+, 2013)J/ApJ/786/120 : Spectropol. survey of classical Be stars (Draper+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/928/145https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/928/145http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/928/145https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/928/145https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/928/145http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/928/145GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/928/145/table2H{alpha} emission line profile characteristics of PleionerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/35] Spectrum identifier number as in Table 1; column added by CDSmeta.id;obsintDateDate of observation (UT)time.epochnullableMJD[53604/58836] Modified Julian Datedtime.epochintEW[-2.7/-0.6] Equivalent widthnmspect.line.eqWidthfloatFpk[1.8/5.4] Peak flux, F/F_c_, of the Ha profilephot.flux;em.line.HalphafloatV/R[0.8/1.1] Violet (V) to red (R) ratiophot.flux;arith.ratiofloatspInteractive spectrum plotmeta.ref.urlcharJ/ApJ/928/145/table1H{alpha} observations of Pleione from the Lowell ObservatoryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/35] Spectrum identifier numbermeta.id;obsintMJD[53604/58836] Modified Julian datedtime.epochintindexedlambda[648.18/659.9] Wavelengthnmem.wldoubleFlux[0.24/5.4] Flux relative to the continuumphot.flux;arith.ratiodouble