A search for ultraviolet circumstellar gas absorption features in alpha Piscis Austrinus (Fomalhaut), a possible Beta Pictoris-like system

1994 ◽  
Vol 425 ◽  
pp. L33 ◽  
Author(s):  
K.-P. Cheng ◽  
Fred C. Bruhweiler ◽  
Yoji Kondo
Keyword(s):  
Gas Absorption ◽  
Beta Pictoris ◽  
Circumstellar Gas ◽  
Absorption Features

First Results from the Goddard High-Resolution Spectrograph: Resolved Velocity and Density Structure in the beta Pictoris Circumstellar Gas

1991 ◽  
Vol 377 ◽  
pp. L49 ◽  
Author(s):  
A. Boggess ◽  
Frederick C. Bruhweiler ◽  
C. A. Grady ◽  
Dennis C. Ebbets ◽  
Yoji Kondo ◽  
...  
Keyword(s):  
High Resolution ◽  
Density Structure ◽  
Beta Pictoris ◽  
Circumstellar Gas ◽  
First Results

scholarly journals Unveiling cloudy exoplanets: the influence of cloud model choices on retrieval solutions

2020 ◽  
Vol 497 (4) ◽  
pp. 4183-4195 ◽  
Author(s):  
Joanna K Barstow
Keyword(s):  
Cloud Model ◽  
Gas Absorption ◽  
Transmission Spectra ◽  
Substantial Fraction ◽  
Retrieval Models ◽  
Hot Jupiters ◽  
Optical Part ◽  
Physical Phenomena ◽  
Absorption Features ◽  
Terminator Region

ABSTRACT In recent years, it has become clear that a substantial fraction of transiting exoplanets have some form of aerosol present in their atmospheres. Transit spectroscopy – mostly of hot Jupiters, but also of some smaller planets – has provided evidence for this, in the form of steep downward slopes from blue to red in the optical part of the spectrum, and muted gas absorption features throughout. Retrieval studies seeking to constrain the composition of exoplanet atmospheres must therefore account for the presence of aerosols. However, clouds and hazes are complex physical phenomena, and the transit spectra that are currently available allow us to constrain only some of their properties. Therefore, representation of aerosols in retrieval models requires that they are described by only a few parameters, and this has been done in a variety of ways within the literature. Here, I investigate a range of parametrizations for exoplanet aerosol and their effects on retrievals from transmission spectra of hot Jupiters HD 189733b and HD 209458b. I find that results qualitatively agree for the cloud/haze itself regardless of the parametrization used, and indeed using multiple approaches provides a more holistic picture; the retrieved abundance of H2O is also very robust to assumptions about aerosols. I also find strong evidence that aerosol on HD 209458b covers less than half of the terminator region, whilst the picture is less clear for HD 189733b.

scholarly journals Resolving complex velocity and gas absorption features with fullwaveform inversion in the Taranaki Basin, New Zealand

2019 ◽  
Vol 2019 (1) ◽  
pp. 1-3
Author(s):  
Yuelian Gong ◽  
Dominic Fell ◽  
Robert Hunn ◽  
Richard Bisley ◽  
Alexander Karvelas ◽  
...  
Keyword(s):  
New Zealand ◽  
Gas Absorption ◽  
Complex Velocity ◽  
Absorption Features

scholarly journals An unusually large gaseous transit in a debris disc

2019 ◽  
Vol 490 (4) ◽  
pp. 5218-5227 ◽  
Author(s):  
Daniela P Iglesias ◽  
Johan Olofsson ◽  
Amelia Bayo ◽  
Sebastian Zieba ◽  
Matías Montesinos ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Spectra ◽  
Photometric Data ◽  
Gas Absorption ◽  
Large Sample ◽  
Circumstellar Gas ◽  
Break Up ◽  
Disc Star

ABSTRACT We present the detection of an unusually large transient gas absorption in several ionized species in the debris disc star HD 37306 using high-resolution optical spectra. We have been analysing a large sample of debris discs searching for circumstellar gas absorptions aiming to determine the frequency of gas in debris discs. HD 37306 stood out showing remarkably broad absorptions superimposed on to several photospheric Ca ii, Fe ii, and Ti ii lines. The observed absorptions, unlike typical exocometary transits, lasted for at least eight days. Here, we analyse simultaneous spectroscopic and photometric data of the event and evaluate different scenarios that might explain the observed features. We conclude that the most likely scenario might be an exocometary break-up releasing a significant amount of gas close to the star, producing an occulting ‘ring’/‘torus’ shape.

scholarly journals Far-Ultraviolet Spectra of Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 405-411
Author(s):  
George Sonneborn
Keyword(s):  
High Resolution ◽  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Central Star ◽  
Uv Spectra ◽  
Stellar Winds ◽  
New Information ◽  
Circumstellar Gas ◽  
Far Ultraviolet ◽  
Absorption Features

The Far Ultraviolet Spectroscopic Explorer (FUSE)> satellite provides a unique opportunity to obtain high-resolution far-UV spectra of a wide variety of astronomical objects, including planetary nebulae. Most FUSE observations of PNe to date have concentrated on the hot central star, providing a very effective way to study the atmosphere of the central star, the surrounding nebula through the absorption features from circumstellar gas. FUSE has found evidence of hot molecular hydrogen in several planetary nebulae, including M27 and BD+30° 3639. Central star spectra also reveal new information about stellar winds, mass loss, and photospheric abundances.

Synthesis of Zn(BH4)2 and Gas Absorption and Release Characteristics of Zn(BH4)2, Ni, or Ti-Added MgH2–Based Alloys

2015 ◽  
Vol 53 (7) ◽  
pp. 500-505 ◽  
Author(s):  
Myoung Youp Song ◽  
Young Jun Kwak ◽  
Sung Nam Kwon ◽  
Seong Ho Lee ◽  
Il Woo Park
Keyword(s):  
Gas Absorption

Gas Absorption and Release Properties of Zn(BH4)2 and MgH2-Zn(BH4)2-Ni-Ti-Fe Alloy

2015 ◽  
Vol 25 (1) ◽  
pp. 43-47
Author(s):  
Young Jun Kwak ◽  
Sung Nam Kwon ◽  
Myoung Youp Song
Keyword(s):  
Gas Absorption
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