Development of Models for Infrared Emission in the Upper Atmosphere.

Infrared emission from the electron irradiated upper atmosphere produced by the Excede: Spectral experiment

Journal of Geophysical Research Atmospheres ◽

10.1029/91ja01269 ◽

1991 ◽

Vol 96 (A11) ◽

pp. 19491 ◽

Cited By ~ 4

Author(s):

Mark E. Fraser ◽

Byron David Green ◽

Robert R. O'Neil

Keyword(s):

Infrared Emission ◽

Upper Atmosphere

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SVEEEETIES: singular vector expansion to estimate Earth-like exoplanet temperatures from infrared emission spectra

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936511 ◽

2020 ◽

Vol 633 ◽

pp. A156

Author(s):

F. Schreier ◽

S. Städt ◽

F. Wunderlich ◽

M. Godolt ◽

J. L. Grenfell

Keyword(s):

Least Squares ◽

Infrared Emission ◽

Upper Atmosphere ◽

High Spectral Resolution ◽

True Temperature ◽

Signal To Noise ◽

Space Telescope ◽

Least Squares Fitting ◽

Future Space ◽

Base Functions

Context. Detailed characterizations of exoplanets are clearly moving to the forefront of planetary science. Temperature is a key marker for understanding atmospheric physics and chemistry. Aims. We aim to retrieve temperatures of N2-O2 dominated atmospheres from secondary eclipse spectroscopic observations of the thermal emission of Earth-like exoplanets orbiting G-, K-, and M-stars, using large-aperture future space telescopes. Methods. A line-by-line radiative transfer code was used to generate synthetic thermal infrared (TIR) observations. The atmospheric temperature is approximated by an expansion with the base vectors defined by a singular value decomposition of a matrix comprising representative profiles. A nonlinear least squares fitting was used to estimate the unknown expansion coefficients. Results. Analysis of the 4.3 and 15 μm CO2 bands in the TIR spectra permits the inference of temperatures even for low signal-to-noise ratios of 5 at medium resolution. Deviations from the true temperature in the upper troposphere and lower-to-mid stratosphere are usually in the range of a few Kelvin, with larger deviations in the upper atmosphere and, less often, in the lower troposphere. Although the performance of the two bands is equivalent in most cases, the longwave TIR is more favorable than the shortwave due to increased star-planet contrast. A high spectral resolution, as provided by the James Webb Space Telescope (JWST) instruments, is important for retaining sensitivity to the upper atmosphere. Furthermore, the selection of an appropriate set of base functions is also key. Conclusions. Temperature in the mid-atmosphere, relevant for understanding habitability, can be suitably characterized by infrared emission spectroscopy with a resolution of at least 1000 (ideally ≈2500). Obtaining the necessary signal-to-noise ratio will be challenging even for JWST, however, it could be feasible with future space missions, such as the Origins Space Telescope or the Large Interferometer for Exoplanets. In the meantime, a least squares fitting with an appropriate set of base functions is also applicable for other classes of planets.

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THE NEAR INFRARED SPECTRUM OF THE NIGHT AIRGLOW OBSERVED FROM HIGH ALTITUDE

Canadian Journal of Physics ◽

10.1139/p64-097 ◽

1964 ◽

Vol 42 (6) ◽

pp. 1037-1045 ◽

Cited By ~ 50

Author(s):

H. P. Gush ◽

H. L. Buijs

Keyword(s):

Infrared Spectrum ◽

Emission Spectrum ◽

High Altitude ◽

Electronic Transition ◽

Near Infrared ◽

Michelson Interferometer ◽

Infrared Emission ◽

Upper Atmosphere ◽

Transition Formula ◽

First Time

The infrared emission spectrum of the upper atmosphere between 1.2 and 2.5 microns has been measured at night by means of a Michelson interferometer carried to an altitude of 90,000 feet by a balloon. The complete Δν = 2 sequence of rotation–vibration OH bands has been observed at a resolution sufficient to resolve the rotational structure. The (0, 0) band of the electronic transition [Formula: see text] of oxygen at 1.27 microns has been observed in the night-sky spectrum for the first time. Its brightness is comparable with that of the (4, 2) OH band at 1.6 microns.

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Atomic oxygen infrared emission in the earth's upper atmosphere

Planetary and Space Science ◽

10.1016/0032-0633(70)90163-7 ◽

1970 ◽

Vol 18 (2) ◽

pp. 271-285 ◽

Cited By ~ 41

Author(s):

G. Kockarts ◽

W. Peetermans

Keyword(s):

Atomic Oxygen ◽

Infrared Emission ◽

Upper Atmosphere

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Detection and Characterization of earth-like Planets

International Astronomical Union Colloquium ◽

10.1017/s0252921100014810 ◽

1997 ◽

Vol 161 ◽

pp. 299-311 ◽

Cited By ~ 22

Author(s):

Jean Marie Mariotti ◽

Alain Léger ◽

Bertrand Mennesson ◽

Marc Ollivier

Keyword(s):

Direct Detection ◽

Contrast Ratio ◽

Angular Size ◽

Physical Nature ◽

Major Axis ◽

Infrared Emission ◽

Space Technology ◽

Semi Major Axis ◽

Earth Like Planets ◽

Visible Wavelengths

AbstractIndirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.

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