The LPSP instrument on OSO 8. II - In-flight performance and preliminary results

Bonnet, R. M.; Lemaire, P.; Vial, J. C.; Artzner, G.; Gouttebroze, P.; Jouchoux, A.; Vidal‐Madjar, A.; Leibacher, J. W.; Skumanich, A.

doi:10.1086/156109

Cited by 78 publications

(48 citation statements)

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“…The percentage of the solar disk covered with these features varies during the solar activity cycle, and the line-and diskintegrated irradiance is tightly correlated with the sunspot number and other solar activity indicators. Furthermore, the line features limb darkening with a related variation of the profile shape in the central reversal, which seems to be a function of the angle off the disk center (Bonnet et al 1978). Therefore it is not easy to predict the shape of disk-integrated profile.…”

Section: Introductionmentioning

confidence: 98%

Evolution of the Solar Lyα Line Profile during the Solar Cycle

Kowalska-Leszczynska

Bzowski

Sokół

et al. 2018

ApJ

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Recent studies of interstellar neutral (ISN) hydrogen observed by the Interstellar Boundary Explorer (IBEX) suggested that the present understanding of the radiation pressure acting on hydrogen atoms in the heliosphere should be revised. There is a significant discrepancy between theoretical predictions of the ISN H signal using the currently used model of the solar Lyman-α profile by Tarnopolski & Bzowski (2009, TB09) and the signal due to ISN H observed by IBEX-Lo. We developed a new model of evolution of the solar Lyman-α profile that takes into account all available observations of the full-disk solar Lyman-α profiles from SUMER/SOHO, provided by Lemaire et al. (2015, L15), covering practically the entire 23rd solar cycle. The model has three components that reproduce different features of the profile. The main shape of the emission line that is produced in the chromosphere is modeled by the kappa function; the central reversal due to absorption in the transition region is modeled by the Gauss function; the spectral background is represented by the linear function. The coefficients of all those components are linear functions of the line-integrated full-disk Lyman-α irradiance, which is the only free parameter of the model. The new model features potentially important differences in comparison with the model by TB09, which was based on a limited set of observations. This change in the understanding of radiation pressure, especially during low solar activity, may significantly affect the interstellar H and D distributions in the inner heliosphere and their derivative populations.

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Section: Introductionmentioning

confidence: 98%

Evolution of the Solar Lyα Line Profile during the Solar Cycle

Kowalska-Leszczynska

Bzowski

Sokół

et al. 2018

ApJ

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“…The multichannel LPSP spectrometer on OSO8 obtained simultaneous line profiles in Lyα (resolution 2 pm), Lyβ (resolution 6 pm), Mg ii h and k, and Ca with a 1 × 10 typical slit (Bonnet et al 1978). The shape of the Ca ii H and K profiles, combined with the telescope pointing, is used to discriminate between quiet and active area.…”

Section: Results From the Oso8/lpsp Spectrometermentioning

confidence: 99%

“…Simultaneous high spectral resolution H i Lyα and Lyβ profiles (along with Mg ii h and k, and Ca ii H and K lines) on the solar disk have been obtained by the multichannel LPSP spectrometer on OSO8 (Bonnet et al 1978) and used to create quiet and active region solar models (Gouttebroze et al 1978;Lemaire et al 1981). Near-simultaneous moderate-resolution lines on the solar disk have been recorded with the HCO spectrometers on both OSO-IV (Dupree & Reeves 1971) and SKYLAB (Vernazza & Reeves 1978).…”

Section: Introductionmentioning

confidence: 99%

The solar hydrogen Lymanαto Lymanβline ratio

Lemaire

Vial

Curdt

et al. 2012

A&A

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Aims. We investigate the variation in the solar hydrogen Lyman α (Lyα) to Lyman β (Lyβ) line ratio as a function of the solar activity by taking into account new results obtained by SoHO/SUMER and TIMED/SEE. Methods. We reanalyze data of quiet and active regions previously collected with the LPSP multichannel instrument on OSO8. We then re-examine data obtained on the solar disk with SUMER and compare them with previous data. In a second step, we use the full Sun H i Lyβ profiles to determine the Lyβ contribution to the SEE profiles obtained with a 0.4 nm full width at half-maximum. The variation in the Lyα to Lyβ line ratio is then measured for part of the solar cycle 23 (2002-2008). Results. We determine the radiance line ratio of the solar H i Lyα to Lyβ line for a quiet Sun area and the relation between the ratio of the Lyα to Lyβ irradiance and the Lyα solar irradiance.

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“…The largest data set of solar Lyα profiles was collected by the LPSP instrument on board OSO-8 (Bonnet et al 1978;Gouttebroze et al 1978). An averaged LPSP profile is shown in blue in Figure 2 (spatial bin of 1″×10″).…”

Section: Discussionmentioning

confidence: 99%

Comparison of Solar Fine Structure Observed Simultaneously in Lyα and Mg ii h

Schmit

Sukhorukov

Pontieu

et al. 2017

ApJ

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The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyα during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg II h and k lines. The Mg II h and Lyα lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg II and Lyα. Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.

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The LPSP instrument on OSO 8. II - In-flight performance and preliminary results

Cited by 78 publications

References 0 publications

Evolution of the Solar Lyα Line Profile during the Solar Cycle

Evolution of the Solar Lyα Line Profile during the Solar Cycle

The solar hydrogen Lymanαto Lymanβline ratio

Comparison of Solar Fine Structure Observed Simultaneously in Lyα and Mg ii h

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