scholarly journals Infrared Tracers of Mass-Loss Histories and Wind-ISM Interactions in Hot Star Nebulae

2007 ◽  
Vol 3 (S250) ◽  
pp. 361-366 ◽  
Author(s):  
Patrick Morris ◽  
Keyword(s):  
Infrared Spectroscopy ◽  
Mass Loss ◽  
Massive Stars ◽  
Dust Formation ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Hot Stars ◽  
Infrared Observations ◽  
Open Time ◽  
Detailed Picture

AbstractInfrared observations of hot massive stars and their environments provide a detailed picture of mass loss histories, dust formation, and dynamical interactions with the local stellar medium that can be unique to the thermal regime. We have acquired new infrared spectroscopy and imaging with the sensitive instruments onboard the Spitzer Space Telescope in guaranteed and open time programs comprised of some of the best known examples of hot stars with circumstellar nebulae, supplementing with unpublished Infrared Space Observatory spectroscopy. Here wepresent highlights of our work on the environment around the extreme P Cygni-type star HDE316285, providing some defining characteristics of the star's evolution and interactions with the ISM at unprecented detail in the infrared.

scholarly journals The European Large Area ISO Survey: Elais

1998 ◽  
Vol 179 ◽  
pp. 112-114
Author(s):  
S. Oliver ◽  
M. Rowan-Robinson ◽  
C. Cesarsky ◽  
L. Danese ◽  
A. Franceschini ◽  
...  
Keyword(s):  
Large Area ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Open Time ◽  
Galactic Sources

I describe a project to survey ∼ 13 square degrees of the sky at 15μm and 90μm with the Infrared Space Observatory (ISO). The European Large Area ISO Survey (ELAIS) is a collaboration involving 19 European institutes (in addition to the authors and others at their institutes the following people and others their institutes are involved I. Gonzalez-Serrano, E. Kontizas, K. Mandolesi, J. Masegosa, K. Mattila, H. Norgaard-Nielsen, I. Perez-Fournon, M. Ward) and is the largest open time project being undertaken by ISO. We expect to detect at least 1000 extra-galactic objects and a similar number of Galactic sources.

scholarly journals Infrared Observations of Mass Loss from Massive Stars

1991 ◽  
Vol 143 ◽  
pp. 281-288
Author(s):  
M.J. Barlow
Keyword(s):  
Ir Spectroscopy ◽  
Mass Loss ◽  
Loss Rate ◽  
Massive Stars ◽  
Mass Loss Rate ◽  
Recombination Line ◽  
Infrared Observations ◽  
Use Of Space ◽  
Ionization Structure ◽  
Line Analysis

The future use of space-borne IR spectroscopy to determine the ionization structure and abundances in the outer winds of WR stars is described. A mass loss rate of 1.7×10-5 M⊙ yr–1 has been derived from 10 μm photometry of the WO2 star Sanduleak 5 (WR 142). The He/H number ratios in the winds of P Cyg and AG Car have been derived from a recombination line analysis of their 1-4 μm spectra and mass loss rates of 2.2×10-5 M⊙ yr–1 and 3.7×10-5 M⊙ yr–1 have been respectively derived for them.

scholarly journals e-MERLIN Radio Continuum Measurements of OB Star Winds in CYG OB2

2015 ◽  
Vol 12 (S316) ◽  
pp. 169-170
Author(s):  
Jack Morford ◽  
Raman Prinja ◽  
Danielle Fenech
Keyword(s):  
Mass Loss ◽  
Massive Star ◽  
Massive Stars ◽  
Radial Distance ◽  
Radio Continuum ◽  
Hot Stars ◽  
Cluster Evolution ◽  
First Results ◽  
Formation And Evolution ◽  
Crucial Parameter

AbstractHere, we report on the first results from the e-MERLIN Cyg OB2 Radio Survey (COBRaS), which is designed to exploit e-MERLIN’s enhanced capabilities to conduct deep-field mapping of the tremendously rich Cyg OB2 association. The project aims to deliver the most detailed radio census of the most massive OB association in the northern hemisphere. There exists considerable evidence for clumping in the winds of hot stars, which has hugely important consequences for mass-loss determinations. The amount of mass lost from a massive star is a crucial parameter required for stellar and cluster evolution models that are paramount to our understanding of the formation and evolution of massive star clusters. Presenting some of the first 20cm (L band) detections of massive stars in Cyg OB2, both accurate mass-loss determinations and constraints upon clumping within their winds are made. These data substantially increase the observational detections of the outer wind of massive stars and in combination with other observations at different wavelengths, COBRaS will greatly advance our knowledge of clumping as a function of radial distance around massive stars.

scholarly journals The 14 μm Band of Carbon Stars

1999 ◽  
Vol 191 ◽  
pp. 267-272 ◽  
Author(s):  
I. Yamamura ◽  
T. de Jong ◽  
L.B.F.M. Waters ◽  
J. Cami ◽  
K. Justtanont
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Wavelength Region ◽  
Circumstellar Envelope ◽  
Carbon Stars ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Absorption Bands ◽  
Different Temperatures

We have studied the absorption bands around 14 μm in the spectra of 11 carbon stars with mass-loss rates ranging from 10−8 to 10−4 M⊙ yr−1, based on data obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). All stars clearly show a C2H2 absorption band peaking at 13.7 μm, while the contribution from HCN molecules is small in this wavelength region. A simple plane-parallel LTE model with two layers at different temperatures is used to derive the C2H2 abundances in the outer photosphere and in the circumstellar envelope. We find that (1) the column density of the hot-layer, placed at about 3R* with a temperature of 1400 K is roughly the same for all stars regardless of the mass-loss rate, and (2) the contribution of cool molecules in the circumstellar envelope increases with the dust mass-loss rate, (3) the abundance of C2H2 in the two layers is about the same, i.e. no obvious depletion of C2H2 molecules seems to occur in the circumstellar envelope.

Recent Mid-Infrared Through Submillimeter Observations of Uranus and Neptune

2021 ◽  
Author(s):  
Glenn Orton ◽  
James Sinclair ◽  
Leigh Fletcher ◽  
Naomi Rowe-Gurney ◽  
Michael Roman ◽  
...  
Keyword(s):  
Thermal Emission ◽  
Far Infrared ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Mid Infrared ◽  
Infrared Observations ◽  
Spatially Resolved ◽  
James Webb Space Telescope ◽  
Imaging And Spectroscopy ◽  
Auroral Emissions

<p>Observations of thermal emission from Uranus and Neptune have been made over a broad wavelength range from ground-based platforms, airborne observatories, Earth-proximal spacecraft and from the Voyager-2 flybys in the 1980s.  Observations since the Voyager flybys have included long-wavelength observations of disk-averaged radiances from the Infrared Space Observatory and the Herschel Space Observatory covering the far-infrared to millimeter range. We present recent airborne spectra from SOFIA covering 17-35 µm, together with Akari and Spitzer spectroscopy at wavelengths extending down to 7 µm, below which contributions from reflected sunlight and potential auroral emissions may confuse the signature of thermal emission.  We also show how these disk-averaged spectra are complemented by ground-based filtered imaging and spectroscopy at 8-10m telescopes, which have enabled spatially resolved measurements, complementing those of Voyager IRIS from several decades ago. The critical insights into the structure, chemistry and dynamics of the atmospheres of these Ice Giants attest to the need for significant parts of this spectral region to be included in the instrument complement to be assigned to spacecraft sent to these planets.  A vigorous program of Earth-based observations in the accessible spectral range should accompany the spacecraft capability in order to track potential seasonal and non-seasonal variability of these planets, as is evident in the atmospheres of both Jupiter and Saturn. The latter would include mid-infrared observations from the James Webb Space Telescope.</p>

scholarly journals Infrared Observations of Circumstellar Molecules

1987 ◽  
Vol 120 ◽  
pp. 327-338 ◽  
Author(s):  
Albert Betz
Keyword(s):  
Infrared Spectroscopy ◽  
Mass Loss ◽  
Abundant Species ◽  
High Resolution Spectroscopy ◽  
Late Type ◽  
Infrared Observations ◽  
Negative Results ◽  
Circumstellar Gas ◽  
Circumstellar Shells ◽  
Vantage Points

This review presents an updated listing of infrared observations of circumstellar molecules. The compendium is restricted to the more abundant species with infrared spectra accessible to groundbased observations. No analysis is offered on the chemical importance of a particular species, and no attempt is made to correlate the infrared work with the much larger body of data available from radio frequency observations. Some discussions of these topics may be found in the more comprehensive reviews listed below. The observations described here include both the successful and the unrewarded efforts. Often the negative results from attempted observations are not widely disseminated, even though such results can sometimes be of significant theoretical value. Discussions of infrared stellar and circumstellar spectroscopy from other vantage points may be found in the following reviews. in 1979 Merrill and Ridgway surveyed the contributions of infrared spectroscopy to studies of stellar photospheres and the near circumstellar environment. The following year Zuckerman (1980) summarized the current state of knowledge on circumstellar molecular clouds with attention given to both infrared and microwave observations. Ridgway and Keady (1981) subsequently noted the importance of infrared spectroscopy for studies of circumstellar gas and dust in the star IRC + 10216. in 1983 Hinkle reviewed the high-resolution spectroscopy of late-type circumstellar shells in general but emphasized chemistry and kinematics. Finally, in the proceedings of the 1984 UCLA meeting on mass-loss, Omont (1985) reviewed the physical and chemical structure of circumstellar envelopes and IRC + 10216 in particular, and Wannier (1985) discussed the significance of infrared spectroscopy for studies of mass-loss in late-type stars.

scholarly journals Infrared spectroscopy with the Infrared Space Observatory

1997 ◽  
Vol 178 ◽  
pp. 373-384
Author(s):  
R. Genzel ◽  
S. Drapatz ◽  
D. Lutz ◽  
C. Wright ◽  
Th. De Graauw
Keyword(s):  
Infrared Spectroscopy ◽  
Short Wavelength ◽  
Emission Lines ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Molecular Emission ◽  
First Results

The Infrared Space Observatory (ISO) is opening the 2.5 to 200 μm band for detailed infrared spectroscopy. Concentrating on ionic and molecular emission lines observed with the Short Wavelength Spectrometer (SWS) we discuss ISO's first results on Galactic and extragalactic sources.

scholarly journals The neon abundance in WC stars. II. ISO-SWS spectroscopy of WR 90 (HD 156385)

1999 ◽  
Vol 193 ◽  
pp. 233-234
Author(s):  
Luc Dessart ◽  
Allan J. Willis ◽  
Paul A. Crowther ◽  
Patrick W. Morris ◽  
D. John Hillier
Keyword(s):  
Fine Structure ◽  
Stellar Evolution ◽  
Reasonable Agreement ◽  
Massive Stars ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Major Discrepancy ◽  
Fine Structure Lines

In general, observationally derived wind compositions of WR stars are in reasonable agreement with predictions from stellar evolution models for massive stars. However, Barlow et al. (1988) identified a major discrepancy for neon in γ2 Vel (WC8+O) using ground-based observations. The advent of the ESA Infrared Space Observatory (ISO) has allowed the study of neon in many more WC stars, using mid-IR fine structure lines ([Ne II] 12.81 μm, [NeIII] 15.55μm and [NEV] 14.32 μm). Willis et al. (1998) used ISO-SWS observations of WR 146 (WC5+O) to derive a neon abundance that was within the range expected theoretically. Here we undertake a study of WR 90 (HD 156385), the only (apparently) single WC7 star in our Galaxy, using ISO-SWS spectroscopy. The only spectroscopic neon feature in the mid-IR of WR 90 is [Ne III] 15.55 μm, in addition to numerous C IV and He II transitions (see Figure 1).

scholarly journals Pulsations as a mass-loss trigger in evolved hot stars

2013 ◽  
Vol 9 (S301) ◽  
pp. 217-220
Author(s):  
Michaela Kraus ◽  
Dieter H. Nickeler ◽  
Maximiliano Haucke ◽  
Lydia Cidale ◽  
Roberto Venero ◽  
...  
Keyword(s):  
Mass Loss ◽  
Main Sequence ◽  
Massive Stars ◽  
Sequence Evolution ◽  
Hot Stars ◽  
Stellar Pulsations ◽  
Pass Through ◽  
Mass Ejection

AbstractDuring their post-main sequence evolution, massive stars pass through several short-lived phases, in which they experience enhanced mass loss in the form of clumped winds and mass ejection events of unclear origin. The discovery that stars populating the blue luminous part of the Hertzsprung-Russell diagram can pulsate suggests that stellar pulsations might influence or trigger enhanced mass loss and eruptions. We present recent results for two objects in different phases: a B[e] star at the end of the main sequence and a B-type supergiant.

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