A spectroscopic study of the binary Be star Phi Persei

Poeckert, R.

doi:10.1086/130828

Cited by 52 publications

(51 citation statements)

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“…More detailed work followed this period, and Slettebak (1966) (confirmed later on by Abt et al 2002) published a measurement of the projected rotational velocity of V sin i = 410-450 km s −1 , which is estimated to be around 85% of the equatorial breakup velocity. Poeckert (1981) presented the first evidence of a companion in ϕ Persei and identified it as a helium star. Based on the velocity curves, he estimated masses of M p = 21 M and M s = 3.4 M .…”

Section: Main Characteristics Of ϕ Perseimentioning

confidence: 99%

“…There are several features in the optical spectrum that display the antiphase Doppler shifts expected for the companion, but these are usually associated with gas near the companion star. These include weak He II 4686 Å emission that may form in a disk close to the companion (Poeckert 1981), He I 4026 Å, 4471 Å "shell" lines formed farther away (Poeckert 1981), and the He I 6678 Å emission line that probably originates in the outer disk of the Be star facing the hot subdwarf (Štefl et al 2000;Hummel & Štefl 2001). There are only six HST measurements of the photospheric lines of the companion itself that were made in the far-ultraviolet spectrum by Gies et al (1998), and we include these in Table 2.…”

Section: Spectroscopic Orbital Determination From Radial Velocity Meamentioning

confidence: 99%

“…In this case, the companion would lose most of its envelope and would appear as a hot, stripped-down He-star remnant. The Be binary star ϕ Persei represents the first detection of a Be star with a hot, faint companion (Poeckert 1981;Thaller et al 1995;Gies et al 1998), and it is one of three such systems known at present (Peters et al 2013). Clearly it is important to study such Be binaries to determine the physical properties of the stars at the conclusion of their transformative interaction.…”

Section: Introductionmentioning

confidence: 99%

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Spectral and spatial imaging of the Be+sdO binaryϕPersei

Mourard

Monnier

Meilland

et al. 2015

A&A

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Aims. The rapidly rotating Be star ϕ Persei was spun up by mass and angular momentum transfer from a now stripped-down, hot subdwarf companion. Here we present the first high angular resolution images of ϕ Persei made possible by new capabilities in longbaseline interferometry at near-IR and visible wavelengths. We analyzed these images to search for the companion, to determine the binary orbit, stellar masses, and fluxes, and to examine the geometrical and kinematical properties of the outflowing disk surrounding the Be star. Methods. We observed ϕ Persei with the MIRC and VEGA instruments of the CHARA Array. MIRC was operated in six-telescope mode, whereas VEGA was configured in four-telescope mode with a change of quadruplets of telescopes during two nights to improve the (u, v) plane coverage. Additional MIRC-only observations were performed to track the orbital motion of the companion, and these were fit together with new and existing radial velocity measurements of both stars to derive the complete orbital elements and distance. We also used the MIRC data to reconstruct an image of the Be disk in the near-IR H-band. VEGA visible broadband and spectro-interferometric Hα observations were fit with analytical models for the Be star and disk, and image reconstruction was performed on the spectrally resolved Hα emission line data. Results. The hot subdwarf companion is clearly detected in the near-IR data at each epoch of observation with a flux contribution of 1.5% in the H band, and restricted fits indicate that its flux contribution rises to 3.3% in the visible. A new binary orbital solution is determined by combining the astrometric and radial velocity measurements. The derived stellar masses are 9.6 ± 0.3 M and 1.2 ± 0.2 M for the Be primary and subdwarf secondary, respectively. The inferred distance (186 ± 3 pc), kinematical properties, and evolutionary state are consistent with membership of ϕ Persei in the α Per cluster. From the cluster age we deduce significant constraints on the initial masses and evolutionary mass transfer processes that transformed the ϕ Persei binary system. The interferometric data place strong constraints on the Be disk elongation, orientation, and kinematics, and the disk angular momentum vector is coaligned with and has the same sense of rotation as the orbital angular momentum vector. The VEGA visible continuum data indicate an elongated shape for the Be star itself, due to the combined effects of rapid rotation, partial obscuration of the photosphere by the circumstellar disk, and flux from the bright inner disk.

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Section: Main Characteristics Of ϕ Perseimentioning

confidence: 99%

Section: Spectroscopic Orbital Determination From Radial Velocity Meamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectral and spatial imaging of the Be+sdO binaryϕPersei

Mourard

Monnier

Meilland

et al. 2015

A&A

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“…Already Plavec (1976) pointed out that if all Be stars were binaries with Roche-lobe filling secondaries, one should observe more eclipsing binaries among them than what is actually observed. While Harmanec (1987) slightly weakened this objection, there is a stronger one: detailed studies of several known Be binaries (ϕ Per = HD 10516: Poeckert 1981, Gies et al 1998; V839 Her = 4 Her: Koubský et al 1997, for instance) clearly demonstrated that the secondaries in those binaries are not Roche-lobe filling objects but very small stars. The same is also true of binaries composed of a Be star and a compact, X-ray companion.…”

Section: Attempts To Explain the Be Phenomenonmentioning

confidence: 99%

On the role of duplicity in the Be phenomenon

Harmanec

Bisikalo

Boyarchuk

et al. 2002

A&A

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Abstract. This paper begins a new series of studies devoted to a critical re-examination of the role of duplicity for the Be phenomenon and for the variability patterns observed for many Be stars. Based on both dynamical and energy considerations and a numerical gas-dynamical modelling, a new hypothesis of the formation of Be envelopes in binaries, via an outflow from a rapidly rotating B star in a detached binary, is outlined. It is shown that such an outflow is facilitated by the presence of a companion to the B star and leads to the formation of an envelope but not to any significant mass exchange between the binary components.

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“…No confirmed examples of the Be + He star stage were known until recent FUV spectroscopy with the Hubble Space Telescope led to the discovery of a hot subdwarf orbiting <f> Per, one of the brightest Be stars in the sky, and in the next section I describe the observations of this remarkable binary. Poeckert (1981) made the first definitive orbital solution for the Be star, <f> Per (P = 127 d). Poeckert noted the unusual appearance of He II A4686 emission with an anti-phase velocity curve, and he argued that the companion must be a hot object in order to ionize helium.…”

Section: Giesmentioning

confidence: 99%

Glimpses of Be Binary Evolution

Gies

2000

International Astronomical Union Colloquium

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Abstract. Models of close binary evolution predict that mass gainers will be spun up to speeds close to the critical rotational velocity while the mass donors will appear as stripped down He stars, white dwarfs, or neutron stars. I argue here that the mass gainers are closely related to the Be stars. I present a list of the known Be binary systems which consists of those with bright, Roche-filling companions and those with faint or undetected companions. Notably absent are Be + B systems which are expected if the Be phase is a stage in the life of a single star. We now have the first example of a Be + He star system in the binary, Per, and taken together with the well known Be X-ray binaries, there is clear evidence that some fraction of Be stars are created in binaries; whether all such rapid rotators are so formed remains unknown.

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A spectroscopic study of the binary Be star Phi Persei

Cited by 52 publications

References 4 publications

Spectral and spatial imaging of the Be+sdO binaryϕPersei

Spectral and spatial imaging of the Be+sdO binaryϕPersei

On the role of duplicity in the Be phenomenon

Glimpses of Be Binary Evolution

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