- ID:
- ivo://CDS.VizieR/J/A+A/644/A67
- Title:
- EUV estimates from CaII H&K activity
- Short Name:
- J/A+A/644/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Atmospheric escape is an important factor shaping the exoplanet population and hence drives our understanding of planet formation. Atmospheric escape from giant planets is driven primarily by the stellar X-ray and extreme- ultraviolet (EUV) radiation. Furthermore, EUV and longer wavelength UV radiation power disequilibrium chemistry in the middle and upper atmosphere. Our understanding of atmospheric escape and chemistry, therefore, depends on our knowledge of the stellar UV fluxes. While the far-ultraviolet fluxes can be observed for some stars, most of the EUV range is unobservable due to the lack of a space telescope with EUV capabilities and, for the more distant stars, to interstellar medium absorption. Thus, it becomes essential to have indirect means for inferring EUV fluxes from features observable at other wavelengths. We present here analytic functions for predicting the EUV emission of F, G, K, and M-type stars from the log R'HK activity parameter that is commonly obtained from ground-based optical observations of the Ca II H&K lines. The scaling relations are based on a collection of about 100 nearby stars with published log R'HK and EUV flux values, where the latter are either direct measurements or inferences from high-quality far-ultraviolet (FUV) spectra. The scaling relations presented here return EUV flux values with an accuracy of about three, which is slightly lower than that of other similar methods based on FUV or X-ray measurements.
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- ID:
- ivo://CDS.VizieR/J/A+A/624/A36
- Title:
- EUV irradiances of the quiet Sun
- Short Name:
- J/A+A/624/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We benchmark new atomic data against a selection of irradiances obtained from medium-resolution quiet-Sun spectra in the extreme ultraviolet (EUV), from 60 to 1040{AA}. We used as a baseline the irradiances measured during solar minimum on 2008 April 14 by the prototype (PEVE) of the Solar Dynamics Observatory Extreme ultraviolet Variability Experiment (EVE). We took into account some inconsistencies in the PEVE data, using flight EVE data and irradiances we obtained from Solar and Heliospheric Observatory (SoHO) Coronal Diagnostics Spectrometer (CDS) data. We performed a differential emission measure and find overall excellent agreement (to within the accuracy of the observations, about 20%) between predicted and measured irradiances in most cases, although we point out several problems with the currently available ion charge-state distributions. We used the photospheric chemical abundances of Asplund et al. (2009ARA&A..47..481A). The new atomic data are nearly complete in this spectral range for medium-resolution irradiance spectra. Finally, we used observations of the active Sun in 1969 to show that the composition of the solar corona up to 1MK is nearly photospheric in this case as well. Variations of a factor of 2 are present for higher-temperature plasma, which is emitted within active regions. These results are in excellent agreement with our previous findings.
- ID:
- ivo://CDS.VizieR/J/ApJS/91/461
- Title:
- EUV spectrum of solar active region
- Short Name:
- J/ApJS/91/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wavelengths and absolute intensities for 269 emission lines from a single active region observed by the Solar EUV Rocket Telescope and Spectrograph (SERTS) on 1989 May 5. For this catalog, the imaged spectra have been spatially averaged over a field of view 7"x276" cutting through the center of AR5464 at S18 W45. Wavelength coverage is 170-450A with a spectral resolution approaching 10,000. Most of the line positions are determined to 5mA or better, representing the highest accuracy yet obtained for solar wavelengths throughout this spectral interval. The relative photometric calibration of the instrument is good to +/-20% over its first-order range, and has been placed onto an absolute scale that should be correct to within a factor less than 2. Where known, identifications, atomic transitions and formation temperatures are also given. The identified lines arise from temperatures that cover the range 4.7<=logT<=6.8, providing information about the Sun's corona and upper transition region. Upper limits to the intensity of any emission line not included here can be estimated from the measured instrumental sensitivity. This averaged EUV spectrum should prove useful as a source of accurate wavelengths and intensities for emission characteristic of the high-temperature plasma associated with a solar active region and small subflare.
- ID:
- ivo://CDS.VizieR/J/ApJ/543/1016
- Title:
- EUV spectrum of solar active region from SERTS-97
- Short Name:
- J/ApJ/543/1016
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Goddard Space Flight Center's Solar EUV Research Telescope and Spectrograph was flown on 1997 November 18, carrying an intensified CCD detector and a multilayer-coated toroidal diffraction grating with enhanced sensitivity over that of a standard gold-coated grating throughout the instrument's 299-353{AA} spectral bandpass. Spectra and spectroheliograms of NOAA Active Region 8108 (N21{deg}, E18{deg}) were obtained with a spectral resolution (instrumental FWHM) of 115m{AA}. Nearly 100 emission lines were observed in the spatially averaged active region spectrum. Spectra and spectroheliograms of quiet areas south of the region were also obtained. An end-to-end radiometric calibration of the rocket instrument was carried out at the Rutherford-Appleton Laboratory in the same facility that was used to calibrate the Coronal Diagnostic Spectrometer experiment on SOHO and using the same EUV light source. The accuracy of this calibration is confirmed by the excellent agreement between the measured and theoretical values of density- and temperature-insensitive line intensity ratios. Nine emission lines of Fe XV are identified in our spectrum; however, large differences between wavelengths in the CHIANTI database and some of the measured solar wavelengths, as well as inconsistencies of various theoretical intensity ratios, suggest a need for improvement in the Fe XV atomic physics parameters and/or the presence of unidentified blending lines.
5745. EUV-SYN
- ID:
- ivo://idoc/medoc/eit_syn/q/epn_core
- Title:
- EUV-SYN
- Short Name:
- eit_syn.epn_core
- Date:
- 16 Nov 2023 13:44:59
- Publisher:
- IDOC
- Description:
- *** EUV-SYN *** Synchronous synoptic maps of the corona in the extreme-UV (EUV), built from series of SoHO/EIT observations, in each of the 4 wavelength bands of the instrument. Synchronous synoptic maps are maps of the EUV radiance in different wavelength bands on the full solar sphere, in heliographic (Carrington) longitude and latitude, where data are taken as close as possible to a reference time. They capture the state of the corona at any given reference time by including data taken as close as possible to this time. EUV-SYN is available as part of the generic MEDOC interface which is currently located at https://idoc-medoc.ias.u-psud.fr/. These interfaces are based on the CNES SiTools2 framework. EUV-SYN is also available from IDL and Python scripts, using a specialization of the generic SiTools2 IDL and Python clients developed by MEDOC.
- ID:
- ivo://CDS.VizieR/J/A+A/485/293
- Title:
- Events of Saturn satellites during 2009 equinox
- Short Name:
- J/A+A/485/293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Saturnian equinox will occur in 2009; i.e., the Sun (and the Earth, very close to the Sun as seen from Saturn) will be in the equatorial plane of Saturn. Eclipses of the satellites by Saturn or mutual eclipses and occultations will occur among the seven first satellites orbiting in the Saturnian equatorial plane. This paper provides predictions of these events, along with information useful for observing them. Such events are uncommon, since they only occur every 15 years during the Saturnian equinox. The present dynamical models of motion of the Saturnian satellites include many effects on their motion. One needs accurate observations, such as mutual events, to determine all the relevant parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/603/A30
- Title:
- Evidence for two distinct giant planet population
- Short Name:
- J/A+A/603/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Analysis of the statistical properties of exoplanets, together with those of their host stars, are providing a unique view into the process of planet formation and evolution. In this paper we explore the properties of the mass distribution of giant planet companions to solar-type stars, in a quest for clues about their formation process. With this goal in mind we studied, with the help of standard statistical tests, the mass distribution of giant planets using data from the exoplanet.eu catalog and the SWEET-Cat database of stellar parameters for stars with planets. We show that the mass distribution of giant planet companions is likely to present more than one population with a change in regime around 4M_{Jup}_. Above this value host stars tend to be more metal poor and more massive and have [Fe/H] distributions that are statistically similar to those observed in field stars of similar mass. On the other hand, stars that host planets below this limit show the well-known metallicity-giant planet frequency correlation. We discuss these results in light of various planet formation models and explore the implications they may have on our understanding of the formation of giant planets. In particular, we discuss the possibility that the existence of two separate populations of giant planets indicates that two different processes of formation are at play.
- ID:
- ivo://CDS.VizieR/J/ApJS/252/23
- Title:
- E(V-I) reddening map of MCs from OGLE-IV RC stars
- Short Name:
- J/ApJS/252/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the most extensive and detailed reddening maps of the Magellanic Clouds (MCs) derived from the color properties of Red Clump (RC) stars. The analysis is based on the deep photometric maps from the fourth phase of the Optical Gravitational Lensing Experiment (OGLE-IV), covering approximately 670deg^2^ of the sky in the Magellanic System region. The resulting maps provide reddening information for 180deg^2^ in the Large Magellanic Cloud (LMC) and 75deg^2^ in the Small Magellanic Cloud (SMC), with a resolution of 1.7'x1.7' in the central parts of the MCs, decreasing to approximately 27'x27' in the outskirts. The mean reddening is E(V-I)=0.100+/-0.043mag in the LMC and E(V-I)=0.047+/-0.025mag in the SMC. We refine methods of calculating the RC color to obtain the highest possible accuracy of reddening maps based on RC stars. Using spectroscopy of red giants, we find the metallicity gradient in both MCs, which causes a slight decrease of the intrinsic RC color with distance from the galaxy center of ~0.002mag/deg in the LMC and between 0.003 and 0.009mag/deg in the SMC. The central values of the intrinsic RC color are 0.886 and 0.877mag in the LMC and SMC, respectively.
- ID:
- ivo://jive.eu/tap
- Title:
- EVN Data Archive TAP service
- Short Name:
- EVN TAP
- Date:
- 24 Mar 2022 14:58:01
- Publisher:
- Joint Institute for VLBI ERIC
- Description:
- The EVN Data Archive's TAP end point. The Table Access Protocol (TAP) lets you execute queries against our database tables, inspect various metadata, and upload your own data. It is thus the VO's premier way to access public data holdings. Tables exposed through this endpoint include: main from the evn schema, obscore from the ivoa schema, columns, groups, key_columns, keys, schemas, tables from the tap_schema schema.
- ID:
- ivo://CDS.VizieR/J/ApJ/885/100
- Title:
- Evolu. star mass-metallicity relation. II.
- Short Name:
- J/ApJ/885/100
- Date:
- 16 Mar 2022 11:50:55
- Publisher:
- CDS
- Description:
- We present the stellar mass-[Fe/H] and mass-[Mg/H] relation of quiescent galaxies in two galaxy clusters at z~0.39 and z~0.54. We derive the age, [Fe/H], and [Mg/Fe] for each individual galaxy using a full-spectrum fitting technique. By comparing with the relations for z~0 Sloan Digital Sky Survey galaxies, we confirm our previous finding that the mass-[Fe/H] relation evolves with redshift. The mass-[Fe/H] relation at higher redshift has lower normalization and possibly steeper slope. However, based on our sample, the mass-[Mg/H] relation does not evolve over the observed redshift range. We use a simple analytic chemical evolution model to constrain the average outflow that these galaxies experience over their lifetime, via the calculation of mass-loading factor. We find that the average mass-loading factor {eta} is a power-law function of galaxy stellar mass, {eta}{prop}M*^-0.21{+/-}0.09^. The measured mass-loading factors are consistent with the results of other observational methods for outflow measurements and with the predictions where outflow is caused by star formation feedback in turbulent disks.