An Ultraviolet Spectral Atlas of VV Cephei during Total Eclipse

Bauer, Walter C.; Bennett, P. D.; Brown, Alexander

doi:10.1086/514334

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…These gray emission profiles produce an effective zero point for much of the spectra in the upper two panels. It also shows that some of the strong chromospheric absorption lines are bottoming out on the emission seen during totality, as was observed in the M + B eclipsing binary VV Cep (Bauer et al 2007). In the sample page plotted here, this can be seen for the 1048.2 Å line of Ar i at phases 0.989 and 0.014.…”

Section: The Spectrum During Chromospheric Eclipsesupporting

confidence: 55%

An Atlas of Far-Ultraviolet Spectra of the Zeta Aurigae Binary 31 Cygni With Line Identifications

Bauer

Bennett

2014

ApJS

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The ζ Aurigae system 31 Cygni (K4 Ib + B4 V) was observed by the FUSE satellite during total eclipse and at three phases during chromospheric eclipse. We present the coadded, calibrated spectra and atlases with line identifications. During total eclipse, emission from high ionization states (e.g., Fe iii and Cr iii) shows asymmetric profiles redshifted from the systemic velocity, while emission from lower ionization states (e.g., Fe ii and O i) appears more symmetric and is centered closer to the systemic velocity. Absorption from neutral and singly ionized elements is detected during chromospheric eclipse. Late in chromospheric eclipse, absorption from the K star wind is detected at a terminal velocity of ∼80 km s −1 . These atlases will be useful for interpreting the far-UV spectra of other ζ Aur systems, as the observed FUSE spectra of 32 Cyg, KQ Pup, and VV Cep during chromospheric eclipse resemble that of 31 Cyg.

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Section: The Spectrum During Chromospheric Eclipsesupporting

confidence: 55%

An Atlas of Far-Ultraviolet Spectra of the Zeta Aurigae Binary 31 Cygni With Line Identifications

Bauer

Bennett

2014

ApJS

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“…Observations of VV Cep continued on for a total of 21 epochs, ending just past first quadrature in 2003. In eclipse, VV Cep has a rich emission line spectrum with more than 2000 features between 1300 and 3150 Å (Bauer, Bennett, & Brown 2007). Immediately after egress, VV Cep shows a complex chromospheric absorption spectrum, while far from eclipse (near quadrature), an inverse P-Cygni "shell" spectrum becomes prominent.…”

Section: Vv Cepheimentioning

confidence: 99%

Chromospheres and Winds of Red Supergiants: An Empirical Look at Outer Atmospheric Structure

Bennett¹

2010

Preprint

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Stars between about 4 and 25 solar masses spend a significant fraction of their post-main sequence lifetime as red supergiants (RSGs) and lose material via stellar winds during this period. For RSGs more massive than 10 solar masses, this mass loss becomes of evolutionary significance, and probably determines the upper mass limit of RSGs in the Hertzsprung-Russell diagram. Despite decades of observations, the driving mechanism responsible for mass loss in RSGs remains unknown. Mainly this is because the optical spectrum accessible from the ground provides almost no useful wind diagnostics, and what information is obtained is spatially averaged over the entire wind volume. However, within the last decade, Hubble Space Telescope (HST) observations of many useful ultraviolet wind diagnostics have been obtained at a high signal-to-noise ratio and spectral resolution. In particular, RSGs in eclipsing binaries can provide spatially resolved observations of stellar chromospheres and winds. I review possible RSG wind acceleration mechanisms, discuss some observational constraints, and present some empirical models of RSG chromospheres and winds.

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“…A rich emission spectrum was observed. Bauer et al (2007) describe this spectrum in detail and provide an atlas with identifications for the ∼2000 emission features seen during totality. Emission from strong low-excitation 5 lines (up to ∼2 eV) is cut by sharp absorption blue-shifted by Figure 2.…”

Section: The System and The One-dimensional Spectramentioning

confidence: 99%

Spatial Extension in the Ultraviolet Spectrum of Vv Cephei

Bauer

Gull

Bennett

2008

The Astronomical Journal

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Two-dimensional processing of Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) echelle spectra of the eclipsing M2 Iab + B binary system, VV Cep, has revealed extended emission in all 21 epochs observed, ranging from midtotality through the first quadrature. In the ultraviolet accessible to STIS (1150-3150 Å), essentially all observed photons originate from the hot component. In total eclipse, a pure emission spectrum is seen, with strong lines from lower levels up to ∼2 eV cut by blue-shifted absorption in the M supergiant wind. Out of eclipse, a continuum is observed upon which a rich absorption spectrum of mostly neutral and singly-ionized iron group elements is superimposed. Out of eclipse, the strongest absorption features sit atop the emission profiles seen during eclipse. Far from eclipse, the neutral lines disappear, and the strongest of the remaining absorption lines develop complex inverse P-Cygni profiles. The continuum and spectrally extended blue wings of the inverse P-Cygni spectral lines show a spatial extension characteristic of the HST/STIS response to an unresolved source. However, the emission components of spectral lines lying longward of the blue-shifted wind absorption typically show flux extending beyond the unresolved hot component, implying formation over an extended region much larger than the size of the binary orbit. This extended line emission is believed to be formed by scattering of photons from the hot component's continuum by ions in ground and low-lying metastable levels in the extended wind of the M supergiant. Extension is observed out of eclipse for lines with lower levels up to approximately 4 eV, but the greatest degree of extension is observed for lines with lower levels less than 2 eV. Radial velocity differences across the spatially extended emission correlate with the aperture position angle, consistent with model predictions for wind flow in a binary system in which the wind outflow is comparable to the orbital velocity, and indicate an orbital plane oriented from +11• E of N (receding) through −169 • (approaching).

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An Ultraviolet Spectral Atlas of VV Cephei during Total Eclipse

Cited by 4 publications

References 8 publications

An Atlas of Far-Ultraviolet Spectra of the Zeta Aurigae Binary 31 Cygni With Line Identifications

An Atlas of Far-Ultraviolet Spectra of the Zeta Aurigae Binary 31 Cygni With Line Identifications

Chromospheres and Winds of Red Supergiants: An Empirical Look at Outer Atmospheric Structure

Spatial Extension in the Ultraviolet Spectrum of Vv Cephei

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