Far‐Ultraviolet Spectroscopy of Venus and Mars at 4 A Resolution with the Hopkins Ultraviolet Telescope on Astro‐2

Feldman, P. D.; Burgh, Eric B.; Durrance, S. T.; Davidsen, A. F.

doi:10.1086/309125

Cited by 82 publications

(101 citation statements)

References 28 publications

(48 reference statements)

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“…The 4P bands at (14, 3)-(14, 6) are due to the optical pumping up by solar Lyman-α line producing the CO 4P (14, v ) band system through resonance with the (14, 0) band (Derrance 1981). Cascading 4P products at (10, 0) and (12, 2) were identified on the disk spectra in addition to the principal C II multiplets (1335 Å) and O I (989 Å), whose existences were previously reported by Feldman et al (2000) and Hubert et al (2012). The intensities of C II (1335 Å) and of O I (989 Å) were approximately 100 R, which are consistent with the past measurements.…”

Section: First Images Of Jupiter and Venussupporting

confidence: 63%

Extreme Ultraviolet Radiation Measurement for Planetary Atmospheres/Magnetospheres from the Earth-Orbiting Spacecraft (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED)

et al. 2014

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The Sprint-A satellite with the EUV spectrometer (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED) was launched in September 2013 by the Epsilon rocket. Now it is orbiting around the Earth (954.05 km × 1156.87 km orbit; the period is 104 minutes) and one has started a broad and varied observation program. With an effective area of more than 1 cm 2 and well-calibrated sensitivity in space, the EUV spectrometer will produce spectral images (520-1480 Å) of the atmospheres/magnetospheres of several planets (Mercury, Venus, Mars, Jupiter, and Saturn) from the Earth's orbit. At the first day of the observation, EUV emissions from the Io plasma torus (mainly sulfur ions) and aurora (H 2 Lyman and Werner bands) of Jupiter have been identified. Continuous 3-month measurement for Io's plasma torus and aurora is planned to witness the sporadic and sudden brightening events occurring on one or both regions. For Venus, the Fourth Positive (A 1 Π -X 1 Σ + ) system of CO and some yet known emissions of the atmosphere were identified even though the exposure was short (8-min). Long-term exposure from April to June (for approximately 2 months) will visualize the Venusian ionosphere and tail in the EUV spectral range. Saturn and Mars are the next targets.

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Section: First Images Of Jupiter and Venussupporting

confidence: 63%

Extreme Ultraviolet Radiation Measurement for Planetary Atmospheres/Magnetospheres from the Earth-Orbiting Spacecraft (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED)

et al. 2014

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“…The O i resonance lines occur in the ultraviolet (UV) and far-ultraviolet (FUV) wavelength range and are observable with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE). The FUV spectra of Venus and Mars observed with the Hopkins Ultraviolet Telescope on Astro-2 (Feldman et al 2000) contain several O i emission lines. The O i intercombination line at 1356 Å and the resonance line at 1304 Å have been identified as strong emission features in the spectra of the Io plasma torus and Io's local and spatially extended atmospheres (Roesler et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Electron Collisional Excitation Rates for O i Using the B ‐Spline R ‐Matrix Approach

Zatsarinny

Tayal

2003

ASTROPHYS J SUPPL S

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The B-spline R-matrix approach has been used to calculate electron collisional excitation strengths and rates for transitions between the 3 P, 1 D, and 1 S states of ground configuration and from these states to the states of the excited 2s 2 2p 3 ns (n ¼ 3 5), 2s 2 2p 3 np (n ¼ 3 4), 2s 2 2p 3 nd (n ¼ 3 4), 2s 2 2p 3 4f , and 2s2p 5 configurations. The nonorthogonal orbitals are used for an accurate description of both the target wave functions and the R-matrix basis functions. The thermally averaged collision strengths are obtained from the collision strengths by integrating over a Maxwellian velocity distribution of electron energies, and these are tabulated over a temperature range from 1000 to 60,000 K. The parametric functions of scaled energy have also been obtained to represent collision strengths over a wide energy range or thermally averaged collision strengths at any desired temperature.

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“…For example, this is the case with a number of solar lines between 80 nm and 120 nm with H 2 Lyman and Werner bands for the case of giant planets. This can also be the situation with the fourth positive band of CO (A 1 P À X 1 R + ) for Mars (Feldman et al 2000). The fluorescence on H 2 has been for example calculated in the case of Jupiter by Liu & Dalgarno (1996), and gives rise to an airglow emission, which can represent the half of the total H 2 airglow.…”

Section: Optically Thick Cases: Example Of the Planetary H-lyman A Emmentioning

confidence: 94%

Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

Barthélemy

Cessateur

2014

J. Space Weather Space Clim.

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The solar UV (UltraViolet) flux, especially the EUV (Extreme UltraViolet) and FUV (Far UltraViolet) components, is one of the main energetic inputs for planetary upper atmospheres. It drives various processes such as ionization, or dissociation which give rise to upper atmospheric emissions, especially in the UV and visible. These emissions are one of the main ways to investigate the upper atmospheres of planets. However, the uncertainties in the flux measurement or modeling can lead to biased estimates of fundamental atmospheric parameters, such as concentrations or temperatures in the atmospheres. We explore the various problems that can be identified regarding the uncertainties in solar/stellar UV flux by considering three examples. The worst case appears when the solar reflection component is dominant in the recorded spectrum as is seen for outer solar system measurements from HST (Hubble Space Telescope). We also show that the estimation of some particular line parameters (intensity and shape), especially Lyman a, is crucial, and that both total intensity and line profile are useful. In the case of exoplanets, the problem is quite critical since the UV flux of their parent stars is often very poorly known.

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Far‐Ultraviolet Spectroscopy of Venus and Mars at 4 A Resolution with the Hopkins Ultraviolet Telescope on Astro‐2

Abstract: Far-ultraviolet spectra of Venus and Mars in the range 820È1840 at D4 resolution were

Cited by 82 publications

References 28 publications

Extreme Ultraviolet Radiation Measurement for Planetary Atmospheres/Magnetospheres from the Earth-Orbiting Spacecraft (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED)

Extreme Ultraviolet Radiation Measurement for Planetary Atmospheres/Magnetospheres from the Earth-Orbiting Spacecraft (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED)

Electron Collisional Excitation Rates for O i Using the B ‐Spline R ‐Matrix Approach

Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

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