Modeling Circumstellar Disks of B-Type Stars With Observations From the Palomar Testbed Interferometer

Grzenia, B. J.; Tycner, C.; Jones, C. E.; Rinehart, Stephen A.; Belle, Gerald van; Sigut, T. A. A.

doi:10.1088/0004-6256/145/5/141

Cited by 7 publications

(6 citation statements)

References 49 publications

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“…Both found only small deviations from circular symmetry in the disc, suggesting the system is seen close to pole-on; Quirrenbach et al (1997) found an axial ratio of 0.95±0.22, from which the minimum inclination angle is 18 • , while Tycner et al (2005) found the axial ratio to be 0.75±0.05, implying a minimum inclination angle of 41 • . Grzenia et al (2013) found a much smaller angular extent of the disc in K band observations from the Palomar Testbed Interferometer, of only 0.71±0.01 mas, although it must be noted that they fit only a single uniform disc component to their observations, and it seems likely the measurement was dominated by the central star. Touhami et al (2013) were unable to resolve the disc in K band with the CHARA Array.…”

Section: Alcyonementioning

confidence: 84%

Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades

White

Pope

Antoci

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The most powerful tests of stellar models come from the brightest stars in the sky, for which complementary techniques, such as astrometry, asteroseismology, spectroscopy, and interferometry can be combined. The K2 Mission is providing a unique opportunity to obtain high-precision photometric time series for bright stars along the ecliptic. However, bright targets require a large number of pixels to capture the entirety of the stellar flux, and bandwidth restrictions limit the number and brightness of stars that can be observed. To overcome this, we have developed a new photometric technique, that we call halo photometry, to observe very bright stars using a limited number of pixels. Halo photometry is simple, fast and does not require extensive pixel allocation, and will allow us to use K2 and other photometric missions, such as TESS, to observe very bright stars for asteroseismology and to search for transiting exoplanets. We apply this method to the seven brightest stars in the Pleiades open cluster. Each star exhibits variability; six of the stars show what are most-likely slowly pulsating Bstar (SPB) pulsations, with amplitudes ranging from 20 to 2000 ppm. For the star Maia, we demonstrate the utility of combining K2 photometry with spectroscopy and interferometry to show that it is not a 'Maia variable', and to establish that its variability is caused by rotational modulation of a large chemical spot on a 10 d time scale.

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Section: Alcyonementioning

confidence: 84%

Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades

White

Pope

Antoci

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…The emission lines are recombination lines that occur in a geometrically thin, equatorial, circumstellar disk, according to a model first proposed by Struve (1931). The model has been modified and further developed by many authors and recently confirmed by direct interferometric observations (Quirrenbach et al 1997;Gies et al 2007;Carciofi et al 2009;Grzenia et al 2013). The disk may entirely disappear and re-appear unpredictably.…”

Section: Introductionmentioning

confidence: 99%

Doppler tomography of the circumstellar disk ofπAquarii

Zharikov

Мирошниченко

Pollmann

et al. 2013

A&A

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Aims. The work is aimed at studying the circumstellar disk of the bright classical binary Be star π Aqr. Methods. We analysed variations of a double-peaked profile of the H α emission line in the spectrum of π Aqr that was observed in many phases during ∼40 orbital cycles in 2004−2013. We applied the discrete Fourier transform (DFT) method to search for periodicity in the peak intensity ratio (V/R). Doppler tomography was used to study the structure of the disk around the primary. Results. The dominant frequency in the power spectrum of the H α V/R ratio is 0.011873 day −1 , which corresponds to a period of 84.2(2) days and agrees with the earlier determined orbital period of the system, P orb = 84.1 days. The V/R shows a sinusoidal variation that is phase-locked with the orbital period. Doppler maps of all our spectra show a non-uniform structure of the disk around the primary: a ring with the inner and outer radii at V in ≈ 450 km s −1 and V out ≈ 200 km s −1 , respectively, along with an extended stable region (spot) at V x ≈ 225 km s −1 and V y ≈ 100 km s −1 . The disk radius of ≈65 R = 0.33 AU was estimated by assuming Keplerian motion of a particle on a circular orbit at the disk's outer edge.

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“…These models have also been able to reproduce the observed correlation seen between Hα and long term variations in visual magnitude, which are interpreted as formation and dissipation of the disk over a long periods of time in Classical Be stars (Sigut & Patel 2013). Observed IR line fluxes Halonen et al 2008) as well as optical and near-IR interferometry (Jones et al 2008;Tycner et al 2008;Mackay et al 2009;Grzenia et al 2013;Sigut et al 2015) computed with Bedisk and Beray models, have been used to put constraints on the several Classical Be star disks.…”

Section: Classical Be Stars and The Beray And Bedisk Codesmentioning

confidence: 95%

Photoionization Models of the Inner Gaseous Disk of the Herbig Be Star Bd+65 1637

Patel

Sigut

Landstreet

2016

ApJ

Self Cite

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We attempt to constrain the physical properties of the inner, gaseous disk of the Herbig Be star BD+65 1637 using non-LTE, circumstellar disk codes and observed spectra (3700 to 10,500Å) from the ESPaDOnS instrument on CFHT. The photoionizing radiation of the central star is assumed to be the sole source of input energy for the disk. We model optical and near-infrared emission lines that are thought to form in this region using standard techniques that have been successful in modeling the spectra of Classical Be stars. By comparing synthetic line profiles of hydrogen, helium, iron and calcium with the observed line profiles, we try to constrain the geometry, density structure, and kinematics of the gaseous disk. Reasonable matches have been found for all line profiles individually; however, no disk density model based on a single powerlaw for the equatorial density was able to simultaneously fit all of the observed emission lines. Amongst the emission lines, the metal lines, especially the Ca ii IR triplet, seem to require higher disk densities than the other lines. Excluding the Ca ii lines, a model in which the equatorial disk density falls as 10 −10 (R * /R) 3 g cm −3 seen at an inclination of 45 • for a 50 R * disk provides reasonable matches to the overall line shapes and strengths. The Ca ii lines seem to require a shallower drop off as 10 −10 (R * /R) 2 g cm −3 to match their strength. More complex disk density models are likely required to refine the match to the BD+65 1637 spectrum.

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Modeling Circumstellar Disks of B-Type Stars With Observations From the Palomar Testbed Interferometer

Cited by 7 publications

References 49 publications

Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades

Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades

Doppler tomography of the circumstellar disk ofπAquarii

Photoionization Models of the Inner Gaseous Disk of the Herbig Be Star Bd+65 1637

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