- Portada
- Volume 93 - Année 2024
- No 3 - 41st Liège International Astrophysical Coll...
- Disk Evolution of Classical Be Stars with Misaligned Binary Companions
Vista(s): 25 (2 ULiège)
Descargar(s): 0 (0 ULiège)
Disk Evolution of Classical Be Stars with Misaligned Binary Companions
Documento adjunto(s)
Version PDF originaleAbstract
Classical Be stars are rapidly rotating B type stars that are surrounded by a gaseous circumstellar decretion disk. Like many massive stars, Be stars are frequently found to exist in binary systems, with a wide array of orbital configurations. Recently, we have computed three- dimensional (3D) smoothed particle hydrodynamics (SPH) models of Be stars with equal-mass binary companions whose orbit is misaligned to the initial plane of the disk and found that the misaligned companion can cause the disk to undergo phenomena of Kozai–Lidov oscillations, and disk-tearing, in addition to the expected tilting and warping of the disk. We now show that these phenomena are not unique to equal-mass systems, but that there is a range of mass ratios for which disk-tearing and Kozai–Lidov oscillations can occur. We also find that an increase in viscosity can suppress these phenomena. Next, we combine our SPH models with the 3D nonlocal thermodynamic equilibrium Monte Carlo radiative transfer code HDUST to produce synthetic spectra of these systems. We show how both phenomena can change the Hα emission line profile, and how disk-tearing creates a detectable polarization signature. We also present a comparison of the observable trends in our disk-tearing model, and how these mimic the changes observed in Pleione (28 Tau). Overall our results demonstrate how phenomena from a misaligned binary companion can cause variations in observables across the whole disk, and that these phenomena need to be considered when analyzing the time evolution of Be star spectra.
This work is distributed under the Creative Commons CC BY 4.0 Licence.
Paper presented at the 41st Liège International Astrophysical Colloquium on “The eventful life of massive star multiples,” University of Liège (Belgium), 15–19 July 2024.
Bibliographie
Baade, D., Rivinius, T., Pigulski, A., Carciofi, A. C., Martayan, C., Moffat, A. F. J., Wade, G. A., Weiss, W. W., Grunhut, J., Handler, G., Kuschnig, R., Mehner, A., Pablo, H., Popowicz, A., Rucinski, S., and Whittaker, G. (2016) Short-term variability and mass loss in Be stars: I. BRITE satellite photometry of η and μ Centauri. A&A, 588, A56. https://doi.org/10.1051/0004-6361/201528026.
Bate, M. R., Bonnell, I. A., and Price, N. M. (1995) Modelling accretion in protobinary systems. MNRAS, 277(2), 362–376. https://doi.org/10.1093/mnras/277.2.362.
Benz, W., Bowers, R. L., Cameron, A. G. W., and Press, W. H. (1990) Dynamic mass exchange in doubly degenerate binaries. I. 0.9 and 1.2 M⊙ stars. ApJ, 348, 647–667. https://doi.org/10.1086/168273.
Bodensteiner, J., Shenar, T., and Sana, H. (2020) Investigating the lack of main-sequence companions to massive Be stars. A&A, 641, A42. https://doi.org/10.1051/0004-6361/202037640.
Carciofi, A. C. and Bjorkman, J. E. (2006) Non-LTE Monte Carlo radiative transfer. I. The thermal properties of Keplerian disks around classical Be stars. ApJ, 639(2), 1081–1094. https://doi.org/10.1086/499483.
Doğan, S., Nixon, C., King, A., and Price, D. J. (2015) Tearing up a misaligned accretion disc with a binary companion. MNRAS, 449(2), 1251–1258. https://doi.org/10.1093/mnras/stv347.
Klement, R., Carciofi, A. C., Rivinius, T., Ignace, R., Matthews, L. D., Torstensson, K., Gies, D., Vieira, R. G., Richardson, N. D., Domiciano de Souza, A., Bjorkman, J. E., Hallinan, G., Faes, D. M., Mota, B., Gullingsrud, A. D., de Breuck, C., Kervella, P., Curé, M., and Gunawan, D. (2019) Prevalence of SED turndown among classical Be stars: Are all Be stars close binaries? ApJ, 885(2), 147. https://doi.org/10.3847/1538-4357/ab48e7.
Klement, R., Rivinius, T., Gies, D. R., Baade, D., Mérand, A., Monnier, J. D., Schaefer, G. H., Lanthermann, C., Anugu, N., Kraus, S., and Gardner, T. (2024) The CHARA array interferometric program on the multiplicity of classical Be stars: New detections and orbits of stripped subdwarf companions. ApJ, 962(1), 70. https://doi.org/10.3847/1538-4357/ad13ec.
Lee, U., Saio, H., and Osaki, Y. (1991) Viscous excretion discs around Be stars. MNRAS, 250(2), 432–437. https://doi.org/10.1093/mnras/250.2.432.
Marr, K. C., Jones, C. E., Tycner, C., Carciofi, A. C., and Silva, A. C. F. (2022) The role of disk tearing and precession in the observed variability of Pleione. ApJ, 928(2), 145. https://doi.org/10.3847/1538-4357/ac551b.
Martin, R. G. and Lepp, S. (2022) Fast nodal precession of the disc around Pleione requires a broken disc. MNRAS, 516(1), L86–L90. https://doi.org/10.1093/mnrasl/slac090.
Martin, R. G., Nixon, C., Lubow, S. H., Armitage, P. J., Price, D. J., Doğan, S., and King, A. (2014) The Kozai–Lidov mechanism in hydrodynamical disks. ApJ, 792(2), L33. https://doi.org/10.1088/2041-8205/792/2/L33.
Martin, R. G., Pringle, J. E., Tout, C. A., and Lubow, S. H. (2011) Tidal warping and precession of Be star decretion discs: Tidal warping of Be star decretion discs. MNRAS, 416(4), 2827–2839. https://doi.org/10.1111/j.1365-2966.2011.19231.x.
Moritani, Y., Nogami, D., Okazaki, A. T., Imada, A., Kambe, E., Honda, S., Hashimoto, O., Mizoguchi, S., Kanda, Y., Sadakane, K., and Ichikawa, K. (2013) Precessing warped Be disk triggering the giant outbursts in 2009 and 2011 in A 0535 + 262/v725 Tau. PASJ, 65(4), 83. https://doi.org/10.1093/pasj/65.4.83.
Okazaki, A. T., Bate, M. R., Ogilvie, G. I., and Pringle, J. E. (2002) Viscous effects on the interaction between the coplanar decretion disc and the neutron star in Be/X-ray binaries. MNRAS, 337(3), 967–980. https://doi.org/10.1046/j.1365-8711.2002.05960.x.
Rivinius, T., Carciofi, A. C., and Martayan, C. (2013) Classical Be stars: Rapidly rotating B stars with viscous Keplerian decretion disks. A&ARv, 21, 69. https://doi.org/10.1007/s00159-013-0069-0.
Štefl, S., Rivinius, T., Carciofi, A. C., Le Bouquin, J.-B., Baade, D., Bjorkman, K. S., Hesselbach, E., Hummel, C. A., Okazaki, A. T., Pollmann, E., Rantakyrö, F., and Wisniewski, J. P. (2009) Cyclic variability of the circumstellar disk of the Be star ζ Tauri: I. Long-term monitoring observations. A&A, 504(3), 929–944. https://doi.org/10.1051/0004-6361/200811573.
Suffak, M., Jones, C. E., and Carciofi, A. C. (2022) Growth and dissipation of Be star discs in misaligned binary systems. MNRAS, 509(1), 931–944. https://doi.org/10.1093/mnras/stab3024.
Suffak, M. W., Jones, C. E., and Carciofi, A. C. (2024) Disc tearing in a Be star: predicted 3D observations. MNRAS, 527(3), 7515–7522. https://doi.org/10.1093/mnras/stad3659.
Townsend, R. H. D., Owocki, S. P., and Howarth, I. D. (2004) Be-star rotation: how close to critical? MNRAS, 350(1), 189–195. https://doi.org/10.1111/j.1365-2966.2004.07627.x.
Wang, L., Gies, D. R., Peters, G. J., Götberg, Y., Chojnowski, S. D., Lester, K. V., and Howell, S. B. (2021) The detection and characterization of Be+sdO binaries from HST/STIS FUV spectroscopy. AJ, 161(5), 248. https://doi.org/10.3847/1538-3881/abf144.
Para citar este artículo
Acerca de: Mark W. Suffak
email : msuffak@uwo.ca