Outbursts and stellar properties of the classical Be star HD 6226
Creators: name: Richardson, Noel D.
name: Thizy, Olivier
name: Bjorkman, Jon E.
name: Carciofi, Alex
name: Rubio, Amanda C.
name: Thomas, Joshua D.
name: Bjorkman, Karen S.
name: Labadie-Bartz, Jonathan
name: Genaro, Matheus
name: Wisniewski, John P.
name: Wang, Luqian
name: Gies, Douglas R.
name: Chojnowski, S. Drew
name: Daly, Andrea
name: Edwards, Thompson
name: Fowler, Carlie
name: Gullingsrud, Allison D.
name: Habel, Nolan
name: James, David J.
name: Kehoe, Emily
name: Kuchta, Heidi
name: Lane, Alexis
name: Miroshnichenko, Anatoly
name: Mishra, Ashish
name: Pablo, Herbert
name: Peploski, Maurice
name: Pepper, Joshua
name: Rodriguez, Joseph E.
name: Siverd, Robert J.
name: Stassun, Keivan G.
name: Stevens, Daniel J.
name: Trucks, Jesica L.
name: Windsor, James
name: Wood, Mackenna
name: Bertrand, Étienne
name: Broussat, Jean-Jacques
name: Bryssinck, Erik
name: Buil, Christian
name: Charbonnel, Stéphane
name: de Bruin, Arnold
name: Daglen, Joe
name: Desnoux, Valerie
name: Dull, James
name: Garde, Olivier
name: Graham, Keith
name: Gurney, Kevin
name: Halsey, Alun
name: Fosanelli, Patrik
name: Fló, Joan Guarro
name: Houpert, Franck
name: James, Foster
name: Kreider, Christian
name: Leadbeater, Robin
name: Lester, Tim
name: Li, Dong
name: Maetz, Alain
name: Stiewing, Albert
name: Somogyi, Peter
name: Terry, Jean-Noël
name: Ubaud, Stéphane
name: Waldschlaeger, Ulrich
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The bright and understudied classical Be star HD 6226 has exhibited multiple outbursts in the last several years during which the star grew a viscous decretion disk. We analyze 659 optical spectra of the system collected from 2017-2020, along with a UV spectrum from the Hubble Space Telescope and high cadence photometry from both TESS and the KELT survey. We find that the star has a spectral type of B2.5IIIe, with a rotation rate of 74% of critical. The star is nearly pole-on with an inclination of $13.4$ degree. We confirm the spectroscopic pulsational properties previously reported, and report on three photometric oscillations from KELT photometry. The outbursting behavior is studied with equivalent width measurements of H$α$ and H$β$, and the variations in both of these can be quantitatively explained with two frequencies through a Fourier analysis. One of the frequencies for the emission outbursts is equal to the difference between two photometric oscillations, linking these pulsation modes to the mass ejection mechanism for some outbursts. During the TESS observation time period of 2019 October 7 to 2019 November 2, the star was building a disk. With a large dataset of H$α$ and H$β$ spectroscopy, we are able to determine the timescales of dissipation in both of these lines, similar to past work on Be stars that has been done with optical photometry. HD 6226 is an ideal target with which to study the Be disk-evolution given its apparent periodic nature, allowing for targeted observations with other facilities in the future.
description: 48 pages including appendices, accepted to MNRAS. MNRAS online version has a 3D printed dynamical spectrum in the appendix. Contact for this section (due to size limitations)