Outbursts and stellar properties of the classical Be star HD 6226
Richardson N.D. Thizy O. Bjorkman J.E. Carciofi A. Rubio A.C. Thomas J.D. Bjorkman K.S. Labadie-Bartz J. Genaro M. Wisniewski J.P. Wang L. Gies D.R. Chojnowski S.D. Daly A. Edwards T. Fowler C. Gullingsrud A.D. Habel N. James D.J. Kehoe E. Kuchta H. Lane A. Miroshnichenko A. Mishra A. Pablo H. Peploski M. Pepper J. Rodriguez J.E. Siverd R.J. Stassun K.G. Stevens D.J. Trucks J.L. Windsor J. Wood M. Bertrand É. Broussat J.-J. Bryssinck E. Buil C. Charbonnel S. De Bruin A. Daglen J. Desnoux V. Dull J. Garde O. Graham K. Gurney K. Halsey A. Fosanelli P. Guarro Fló J. Houpert F. James F. Kreider C. Leadbeater R. Lester T. Li D. Maetz A. Stiewing A. Somogyi P. Terry J.-N. Ubaud S. Waldschlaeger U.
1 December 2021Oxford University Press
Monthly Notices of the Royal Astronomical Society
2021#508Issue 22002 - 2018 pp.
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 disc. We analyse 659 optical spectra of the system collected from 2017 to 2020, along with a ultraviolet spectrum from the Hubble Space Telescope and high cadence photometry from both Transiting Exoplanet Survey Satellite (TESS) and the Kilodegree Extremely Little Telescope (KELT) survey. We find that the star has a spectral type of B2.5IIIe, with a rotation rate of 74 per cent of critical. The star is nearly pole-on with an inclination of 13°4. We confirm the spectroscopic pulsational properties previously reported, and report on three photometric oscillations from KELT photometry. The outbursting behaviour 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 disc. With a large data set of H α and H β spectroscopy, we are able to determine the time-scales 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 disc-evolution given its apparent periodic nature, allowing for targeted observations with other facilities in the future.
circumstellar matter , stars: early-type , stars: emission-line, Be , stars: individual: HD 6226 , stars: oscillations , stars: rotation
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Department of Physics and Astronomy, Embry-Riddle Aeronautical University, 3700 Willow Creek Road, Prescott, 86301, AZ, United States
The Astronomical Ring for Access to Spectroscopy (ARAS) Group, Department of Physics and Astronomy, The University of Toledo, Toledo, 43606-3390, OH, United States
Ritter Observatory, Department of Physics and Astronomy, The University of Toledo, Toledo, 43606-3390, OH, United States
Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Brazil
Department of Physics, Clarkson University, 8 Clarkson Ave, Potsdam, 13699, NY, United States
Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, 73019, OK, United States
Center for High Angular Resolution Astronomy, Department of Physics and Astronomy, Georgia State University, PO Box 5060, Atlanta, 30302-5060, GA, United States
Apache Point Observatory, New Mexico State University, PO Box 59, Sunspot, 88349-0059, NM, United States
ASTRAVEO, LLC, PO Box 1668, Gloucester, 01931, MA, United States
Department of Physics and Astronomy, University of North Carolina at Greensboro, PO Box 26170, Greensboro, 27402-6170, NC, United States
Main Astronomical Observatory of the Russian Academy of Sciences, Pulkovskoye Shosse, 65, Saint-Petersburg, 196140, Russian Federation
Fesenkov Astrophysical Institute, Observatory, 23, Almaty, 050020, Kazakhstan
American Association of Variable Star Observers, 49 Bay State Road, Cambridge, 02138, MA, United States
Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, 18015, PA, United States
Center for Astrophysics - Harvard & Smithsonian, 60 Garden St, Cambridge, 02138, MA, United States
Gemini Observatory, NSFs NOIRLab, 670 N. Aohoku Place, Hilo, 96720, HI, United States
Department of Physics and Astronomy, Vanderbilt University, Nashville, 37235, TN, United States
Department of Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, 16802, PA, United States
Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, 525 Davey Lab, University Park, 16802, PA, United States
Abrams Planetarium, Michigan State University, East Lansing, 48824, MI, United States
Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, 86011, AZ, United States
The College of Idaho, Caldwell, 83605, ID, United States
Department of Physics and Astronomy
The Astronomical Ring for Access to Spectroscopy (ARAS) Group
Ritter Observatory
Instituto de Astronomia
Department of Physics
Homer L. Dodge Department of Physics and Astronomy
Center for High Angular Resolution Astronomy
Apache Point Observatory
ASTRAVEO
Department of Physics and Astronomy
Main Astronomical Observatory of the Russian Academy of Sciences
Fesenkov Astrophysical Institute
American Association of Variable Star Observers
Department of Physics
Center for Astrophysics - Harvard & Smithsonian
Gemini Observatory
Department of Physics and Astronomy
Department of Astronomy & Astrophysics
Center for Exoplanets and Habitable Worlds
Abrams Planetarium
Department of Astronomy and Planetary Science
The College of Idaho
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