- ID:
- ivo://CDS.VizieR/J/ApJS/181/351
- Title:
- Solar flux model in 30-1300nm wavelength range
- Short Name:
- J/ApJS/181/351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Solar photon scattering probabilities (g values) have been calculated for discrete transitions in 12 species, in a format designed primarily to allow analysis of spacecraft observations from MESSENGER and BepiColombo at Mercury. The results support observations using the MESSENGER Ultraviolet and Visible Spectrometer spectrograph experiment operating over the spectral range 1150-6000{AA} and the BepiColombo spectrograph in the range 550-3150{AA}. Significant radial velocity dependence is shown for most of the emission lines, a critical factor for interpretation of the observed spectra. The g values have general application for solar system emission sources dominated by scattering of the solar flux.
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- ID:
- ivo://CDS.VizieR/J/other/SoPh/295.14
- Title:
- SOLAR-ISS Spectrum covering 165-3000nm
- Short Name:
- J/other/SoPh/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The accurate measurement of the solar spectrum at the top of the atmosphere and its variability are fundamental inputs for solar physics (Sun modeling), terrestrial atmospheric photochemistry, and Earth's climate (climate's modeling). These inputs were the prime objective set in 1996 for the SOLAR International Space Station (ISS). The SOLAR package represents a set of three solar instruments measuring the total and spectral absolute irradiance from 16nm to 3088nm. SOLAR was launched with the European Columbus space laboratory in February 2008 aboard the NASA Space Shuttle Atlantis. SOLAR on the ISS tracked the Sun until it was decommissioned in February 2017. The SOLar SPECtrum (SOLSPEC) instrument of the SOLAR payload allowed the measurement of solar spectra in the 165-3000nm wavelength range for almost a decade. Until the end of its mission, SOLAR/SOLSPEC was pushed to its limits to test how it was affected by space environmental effects (external thermal factors) and to better calibrate the space-based spectrometer. To that end, a new solar reference spectrum (SOLAR-ISS - V1.1) representative of the 2008 solar minimum was obtained from the measurements made by the SOLAR/SOLSPEC instrument and its calibrations. The main purpose of this article is to improve the SOLAR-ISS reference spectrum (between 165 and 180nm in the far ultraviolet, between 216.9 and 226.8nm in the middle ultraviolet, and between 2400 and 3000nm in the near-infrared). SOLAR-ISS has a resolution better than 0.1nm between 165 and 1000nm, and 1nm in the 1000-3000nm wavelength range. Finally, a first comparison is made between the new SOLAR-ISS spectrum (V2.0) and the Total and Spectral solar Irradiance Sensor (TSIS-1) spectrum obtained from its first observations from the ISS. Indeed, the launch of TSIS in December 2017 provides a new light on the absolute determination of the solar spectrum and especially in the infrared region of the spectrum.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A125
- Title:
- Solar lines from Ceres spectra
- Short Name:
- J/A+A/544/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Present knowledge of the solar spectrum is limited because it is very difficult to observe the integrated solar spectrum at high resolution. The reflected solar light from asteroids has been shown to provide a relatively straightforward integrated and unmodified solar spectrum. We exploit this methodology to improve our knowledge of solar photospheric line positions both in terms of line number and precision with respect to the available solar line atlas.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A26
- Title:
- Solar Lyman irradiance line profiles
- Short Name:
- J/A+A/581/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate hydrogen spectra emitted by the entire solar disc in the Ly-{alpha} and Ly-{beta} lines are valuable for deriving the distribution and the behaviour of atomic hydrogen in the heliosphere, for understanding the UV emissions of solar type stars better, and finally for estimating the solar energy input that mainly initiates the chemical processes occurring in the planetary and cometary outer atmospheres. In this paper we want to accurately determine the irradiance solar spectral profiles of Ly-{alpha} and Ly-{beta} and their evolution through the solar activity cycle 23. The SUMER/SOHO spectrometer is a slit spectrometer that is only able to analyse a small part of the solar image. Consequently, we used the scattered light properties of the telescope to obtain average spectra over the solar disc. Then the profile is calibrated using the SOLSTICE/UARS and TIMED/SEE irradiance spectra.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/24
- Title:
- Solar models with accretion. I.
- Short Name:
- J/ApJ/743/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We generate new standard solar models using newly analyzed nuclear fusion cross sections and present results for helioseismic quantities and solar neutrino fluxes. The status of the solar abundance problem is discussed. We investigate whether nonstandard solar models with accretion from the protoplanetary disk might alleviate this problem. We examine a broad range of models, analyzing metal-enriched and metal-depleted accretion and three scenarios for the timing of accretion. Only partial solutions are found. For metal-rich accreted material (Z_ac_>~0.018) there exist combinations of accreted mass and metallicity that bring the depth of the convective zone into agreement with the helioseismic value. For the surface helium abundance, the helioseismic value is reproduced if metal-poor or metal-free accretion is assumed (Z_ac_<~0.09). In both cases a few percent of the solar mass must be accreted. Precise values depend on when accretion takes place. We do not find a simultaneous solution to both problems but speculate that changing the hydrogen-to-helium mass ratio in the accreted material may lead to more satisfactory solutions. We also show that, with current data, solar neutrinos are already a very competitive source of information about the solar core and can help constraining possible accretion histories. Even without helioseismic constraints, solar neutrinos rule out the possibility that more than 0.02M_{sun}_ from the protoplanetary disk were accreted after the Sun settled on the main sequence. Finally, we discuss how measurements of neutrinos from the CN cycle could shed light on the interaction between the early Sun and its protoplanetary disk.
- ID:
- ivo://CDS.VizieR/J/ApJS/210/12
- Title:
- Solar photoionization rates
- Short Name:
- J/ApJS/210/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extreme UV (EUV) spectra from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Solar EUV Experiment are used to infer photoionization rates in the inner heliosphere. Relating these rates to various proxies describing the solar EUV radiation, we construct a multi-linear model which allows us to extrapolate ionization rates back to periods when no routine measurements of the solar EUV spectral distribution have been available. Such information is important, e.g., for comparing conditions of the interstellar neutral particles in the inner heliosphere at the time of Ulysses/GAS observations with conditions during the more recent observations of the Interstellar Boundary Explorer. From a period of 11 yr when detailed spectra from both TIMED and three proxies -- Solar and Heliospheric Observatory/CELIAS/SEM-rates, F10.7 radio flux, and Mg II core-to-wing indices -- have been available, we conclude that the simple model is able to reproduce the photoionization rates with an uncertainty of typically 5%.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/901
- Title:
- Solar quiescent filament channels
- Short Name:
- J/ApJ/721/901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the structure and dynamics of quiescent filament channels observed by Hinode/XRT and STEREO/EUVI at the solar minimum 23/24 from 2006 November to 2008 December. For 12 channels identified on the solar disk (Group I channels), we find that the morphology of the structure on the two sides of the channel is asymmetric in both X-rays and EUV: the eastern side has curved features while the western side has straight features. We interpret the results in terms of a magnetic flux rope model. The asymmetry in the morphology is due to the variation in axial flux of the flux rope along the channel, which causes the field lines from one polarity to turn into the flux rope (curved feature), while the field lines from the other polarity are connected to very distant sources (straight). For most of the 68 channels identified by cavities at the east and west limbs (Group II channels), the asymmetry cannot be clearly identified, which is likely due to the fact that the axial flux may be relatively constant along such channels. Corresponding cavities are identified only for 5 of the 12 Group I channels, while Group II channels are identified for all of the 68 cavity pairs. The studied filament channels are often observed as dark channels in X-rays and EUV. Sheared loops within Group I channels are often seen in X-rays, but are rarely seen in Group II channels as shown in the X-ray Telescope daily synoptic observations. A survey of the dynamics of studied filament channels shows that filament eruptions occur at an average rate of 1.4 filament eruptions per channel per solar rotation.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A130
- Title:
- Solar sibling candidates chemical abundances
- Short Name:
- J/A+A/619/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Finding solar siblings, that is, stars that formed in the same cluster as the Sun, will yield information about the conditions at the Sun's birthplace. Finding possible solar siblings is difficult since they are spread widely throughout the Galaxy. We search for solar sibling candidates in AMBRE, the very large spectra database of solar vicinity stars. Since the ages and chemical abundances of solar siblings are very similar to those of the Sun, we carried out a chemistry- and age-based search for solar sibling candidates. We used high-resolution spectra to derive precise stellar parameters and chemical abundances of the stars. We used these spectroscopic parameters together with Gaia DR2 astrometric data to derive stellar isochronal ages. Gaia data were also used to study the kinematics of the sibling candidates. From the about 17000 stars that are characterized within the AMBRE project, we first selected 55 stars whose metallicities are closest to the solar value (-0.1<=[Fe/H]<=0.1dex). For these stars we derived precise chemical abundances of several iron-peak, {alpha}- and neutron-capture elements, based on which we selected 12 solar sibling candidates with average abundances and metallicities between -0.03 to 0.03dex. Our further selection left us with 4 candidates with stellar ages that are compatible with the solar age within observational uncertainties. For the 2 of the hottest candidates, we derived the carbon isotopic ratios, which are compatible with the solar value. HD186302 is the most precisely characterized and probably the most probable candidate of our 4 best candidates. Very precise chemical characterization and age estimation is necessary to identify solar siblings. We propose that in addition to typical chemical tagging, the study of isotopic ratios can give further important information about the relation of sibling candidates with the Sun. Ideally, asteroseismic age determinations of the candidates could solve the problem of imprecise isochronal ages.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A1
- Title:
- SOLAR/SOLSPEC Spectral Irradiance - 0.5-3000nm
- Short Name:
- J/A+A/611/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since April 5, 2008 and up to February 15, 2017, the SOLar SPECtrometer (SOLSPEC) instrument of the SOLAR payload on board the International Space Station (ISS) has performed accurate measurements of solar spectral irradiance (SSI) from the middle ultraviolet to the infrared (165 to 3088nm). These measurements are of primary importance for a better understanding of solar physics and the impact of solar variability on climate. In particular, a new reference solar spectrum (SOLAR-ISS) is established in April 2008 during the solar minima of cycles 23-24 thanks to revised engineering corrections, improved calibrations, and advanced procedures to account for thermal and aging corrections of the SOLAR/SOLSPEC instrument. The main objective of this article is to present a new high-resolution solar spectrum with a mean absolute uncertainty of 1.26% at 1{sigma} from 165 to 3000nm. This solar spectrum is based on solar observations of the SOLAR/SOLSPEC space-based instrument. The SOLAR/SOLSPEC instrument consists of three separate double monochromators that use concave holographic gratings to cover the middle ultraviolet (UV), visible (VIS), and infrared (IR) domains. Our best ultraviolet, visible, and infrared spectra are merged into a single absolute solar spectrum covering the 165-3000nm domain. The resulting solar spectrum has a spectral resolution varying between 0.6 and 9.5nm in the 165-3000nm wavelength range. We build a new solar reference spectrum (SOLAR-ISS) by constraining existing high-resolution spectra to SOLAR/SOLSPEC observed spectrum. For that purpose, we account for the difference of resolution between the two spectra using the SOLAR/SOLSPEC instrumental slit functions. Using SOLAR/SOLSPEC data, a new solar spectrum covering the 165-3000nm wavelength range is built and is representative of the 2008 solar minimum. It has a resolution better than 0.1nm below 1000nm and 1nm in the 1000-3000nm wavelength range. The new solar spectrum (SOLAR-ISS) highlights significant differences with previous solar reference spectra and with solar spectra based on models. The integral of the SOLAR-ISS solar spectrum yields a total solar irradiance of 1372.3+/-16.9W/m^2^ at 1{sigma}, that is yet 11W/m^2^ over the value recommended by the International Astronomical Union in 2015.
- ID:
- ivo://CDS.VizieR/J/other/SoPh/291.3527
- Title:
- SOLAR/SOLSPEC UV SSI from 2008-2015
- Short Name:
- J/other/SoPh/291
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate measurements of the solar spectral irradiance (SSI) and its temporal variations are of primary interest to better understand solar mechanisms, and the links between solar variability and Earth's atmosphere and climate. The SOLar SPECtrum (SOLSPEC) instrument of the Solar Monitoring Observatory (SOLAR) payload onboard the International Space Station (ISS) has been built to carry out SSI measurements from 165 to 3088nm. We focus here on the ultraviolet (UV) part of the measured solar spectrum (wavelengths less than 400 nm) because the UV part is potentially important for understanding the solar forcing of Earth's atmosphere and climate. We present here SOLAR/SOLSPEC UV data obtained since 2008, and their variations in three spectral bands during Solar Cycle 24. They are compared with previously reported UV measurements and model reconstructions, and differences are discussed.
