Texes Observations of M Supergiants: Dynamics and Thermodynamics of Wind Acceleration

  title={Texes Observations of M Supergiants: Dynamics and Thermodynamics of Wind Acceleration},
  author={G. Harper and M. Richter and N. Ryde and A. Brown and J. Brown and T. Greathouse and S. Strong},
  journal={The Astrophysical Journal},
We have detected [Fe II] 17.94 μm and 24.52 μm emission from a sample of M supergiants (μ Cep, α Sco, α Ori, CE Tau, AD Per, and α Her) using the Texas Echelon Cross Echelle Spectrograph on NASA's Infrared Telescope Facility. These low opacity emission lines are resolved at R 50, 000 and provide new diagnostics of the dynamics and thermodynamics of the stellar wind acceleration zone. The [Fe II] lines, from the first excited term (a 4 F), are sensitive to the warm plasma where energy is… Expand
The inhomogeneous submillimeter atmosphere of Betelgeuse
The mechanisms responsible for heating the extended atmospheres of early-M spectral-type supergiants are poorly understood. So too is the subsequent role these mechanisms play in driving the largeExpand
SOFIA-EXES Mid-IR Observations of [Fe II] Emission from the Extended Atmosphere of Betelgeuse
We present a NASA-DLR SOFIA-Echelon Cross Echelle Spectrograph (EXES) and NASA Infrared Telescope Facility-Texas Echelon Cross Echelle Spectrograph (TEXES) mid-IR R ≃ 50,000 spectral study ofExpand
Temporal Evolution of the Size and Temperature of Betelgeuse's Extended Atmosphere
Spatially resolved multi-wavelength centimeter continuum observations of cool evolved stars can not only constrain the morphology of the radio emitting regions, but can also directly probe the meanExpand
Spatially resolving the atmospheric dynamics over the surface of red supergiants with the Very Large Telescope Interferometer
The mass-loss mechanism in red supergiants is a long-stand-ing problem. The milliarcsecond angular resolution achieved by infrared long-baseline interferometry provides us with the only way toExpand
Discovery of a detached HI gas shell surrounding alpha Orionis
We report the detection of the HI line at 21 cm in the direction of alpha Ori with the Nancay Radiotelescope and with the Very Large Array. The observations confirm the previous detection of HIExpand
Vigorous atmospheric motion in the red supergiant star Antares
The two-dimensional velocity field map obtained from the near-infrared spectro-interferometric imaging reveals vigorous upwelling and downdrafting motions of several huge gas clumps at velocities ranging from about −20 to +20 kilometres per second in the atmosphere, which extends out to about 1.7 stellar radii. Expand
Imaging the outward motions of clumpy dust clouds around the red supergiant Antares with VLT/VISIR
We present a 0.5"-resolution diffraction-limited 17.7 micron image of the red supergiant Antares obtained with the VLT mid-infrared instrument VISIR. The VISIR image shows six clumpy dust cloudsExpand
ALMA and VLA reveal the lukewarm chromospheres of the nearby red supergiants Antares and Betelgeuse
We first present spatially resolved ALMA and VLA continuum observations of the early-M red supergiant Antares to search for the presence of a chromosphere at radio wavelengths. We resolve theExpand
A high-contrast imaging survey of nearby red supergiants
Abstract Mass-loss in cool supergiants remains poorly understood, but is one of the key elements in their evolution towards exploding as supernovae. Some show evidence of asymmetric mass loss,Expand
Evolution of solar-type stellar wind
By extending our self-consistent MHD simulations for the solar wind, we study the evolution of stellar winds of solar-type stars from early main sequence stage to red giant phase. Young solar-typeExpand


VLA Observations of ζ Aurigae: Confirmation of the Slow Acceleration Wind Density Structure
Studies of the winds from single K and early M evolved stars indicate that these flows typically reach a significant fraction of their terminal velocity within the first couple of stellar radii. TheExpand
Modeling the Variable Chromosphere of α Orionis
A spectral analysis of the prototypical red supergiant star a Ori that is based on near-UV, optical, and near-IR high-dispersion spectra obtained between 1992 September and 1999 July with the SpaceExpand
GHRS Observations of Cool Low-Gravity Stars. III. Plasma Flows and Turbulence in the Outer Atmosphere of α Orionis (M2 Iab)
We present the results of a Goddard High Resolution Spectrograph (GHRS) study of flow and turbulent velocities in the outer atmosphere of the M2 Iab supergiant α Ori. Ions with observed chromosphericExpand
The outer atmosphere of the M-type supergiant α Orionis: K I 7699 Å emission
Spatially-resolved high-resolution long-slit spectra of Betelgeuse's circumstellar shell are described for a spectral window centered on the 7699 A resonance line of neutral potassium. The K iExpand
The warm circumstellar envelope and wind of the G9 IIb star HR 6902
IUE observations of the eclipsing binary system HR 6902 obtained at various epochs spread over four years indicate the presence of warm circumstellar material enveloping the G9 IIb primary. TheExpand
A Spatially Resolved, Semiempirical Model for the Extended Atmosphere of α Orionis (M2 Iab)
We have constructed a detailed mean density and temperature model for the extended outer atmosphere of the O-rich supergiant Betelgeuse (??Ori [M2 Iab]), which extends from 1.0 to 10.0 stellar radii.Expand
Spatially Resolved STIS Spectroscopy of α Orionis: Evidence for Nonradial Chromospheric Oscillation from Detailed Modeling*
Four spatially resolved near-UV raster scans across the chromospheric disk of α Ori, obtained with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, reveal mean chromosphericExpand
Electron Density and Turbulence Gradients within the Extended Atmosphere of the M Supergiant Betelgeuse (α Orionis)
The extended atmosphere of the M supergiant Betelgeuse is complex with cool plasma dominating the structure by mass and small amounts of embedded hotter chromospheric plasma. A major challenge is toExpand
GHRS observations of cool, low-gravity star. 2: Flow and turbulent velocities in the outer atmosphere of gamma CRU CIS (M3.4 III)
The Goddard High Resoulution Spectrograph (GHRS) on the Hubble Space Telescope (HST) has been used to obtain medium (R = 20,000) and high (R = 85,000) resoultion UV spectra of chromosphere emissionExpand
On the relationship between coronae and mass loss in late-type stars
High-dispersion spectra taken with the IUE are used to examine the temperature stratification of the wind of the hybrid atmosphere star Alpha TrA (K4 II). C IV emission is shown to have a line widthExpand