- 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.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/425/34
- Title:
- ExoMol line lists for BeH, MgH and CaH
- Short Name:
- J/MNRAS/425/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate line lists for three molecules, BeH, MgH and CaH, in their ground electronic states are presented. These line lists are suitable for temperatures relevant to exoplanetary atmospheres and cool stars (up to 2000K). A combination of empirical and ab initio methods is used. The rovibrational energy levels of BeH, MgH and CaH are computed using the programs Level and DPotFit in conjunction with 'spectroscopic' potential energy curves (PECs). The PEC of BeH is taken from the literature, while the PECs of CaH and MgH are generated by fitting to the experimental transition energy levels. Both spin-rotation interactions (except for BeH, for which it is negligible) and non-adiabatic corrections are explicitly taken into account. Accurate line intensities are generated using newly computed ab initio dipole moment curves for each molecule using high levels of theory. Full line lists of rotation-vibration transitions for ^9^BeH, ^24^MgH, ^25^MgH, ^26^MgH and ^40CaH are made available in an electronic form as supplementary data to this article and at www.exomol.com .
- ID:
- ivo://CDS.VizieR/J/MNRAS/440/1649
- Title:
- ExoMol line lists for CH4
- Short Name:
- J/MNRAS/440/1649
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new hot line list is calculated for ^12^CH_4_ in its ground electronic state. This line list, called 10to10, contains 9.8 billion transitions and should be complete for temperatures up to 1500K. It covers the wavelengths longer than 1{mu}m and includes all transitions to upper states with energies below hc 18000cm^-1^ and rotational excitation up to J=39. The line list is computed using the eigenvalues and eigenfunctions of CH_4_ obtained by variational solution of the SCHR equation for the rotation-vibration motion of nuclei employing program TROVE and a new 'spectroscopic' potential energy surface (PES) obtained by refining an ab initio PES (CCSD(T)-F12c/aug-cc-pVQZ) in a least-squares fitting to the experimentally derived energies with J=0, 1, 2, 3, 4 as extracted from the HITRAN database. The dipole transition probabilities are represented by the Einstein-A coefficients obtained using a previously reported ab initio dipole moment surface (CCSD(T)-F12c/aug-cc-pVTZ). Detailed comparisons with other available sources of methane transitions including HITRAN, experimental compilations and other theoretical line lists show that these sources lack transitions both higher temperatures and near infrared wavelengths. The 10to10 line list is suitable for modelling atmospheres of cool stars and exoplanets.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/1704
- Title:
- ExoMol line lists for formaldehyde H_2_CO
- Short Name:
- J/MNRAS/448/1704
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A computed line list for formaldehyde, H_2_^12^C^16^O, applicable to temperatures up to T=1500K is presented. An empirical potential energy and ab initio dipole moment surfaces are used as the input to nuclear motion program TROVE. The resulting line list, referred to as AYTY, contains 10.3 million rotational-vibrational states and around 10 billion transition frequencies. Each transition includes associated Einstein- A coefficients and absolute transition intensities, for wavenumbers below 10000cm^-1^ and rotational excitations up to J=70. Room-temperature spectra are compared with laboratory measurements and data currently available in the HITRAN database. These spectra show excellent agreement with experimental spectra and highlight the gaps and limitations of the HITRAN data. The full line list is available from the CDS database as well as at www.exomol.com.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/2337
- Title:
- ExoMol line lists for phosphine (PH_3_)
- Short Name:
- J/MNRAS/446/2337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A comprehensive hot line list is calculated for ^31^PH_3_ in its ground electronic state. This line list, called SAlTY, contains almost 16.8 billion transitions between 7.5 million energy levels and it is suitable for simulating spectra up to temperatures of 1500K. It covers wavelengths longer than 1um and includes all transitions to upper states with energies below hc.18000cm^-1^ and rotational excitation up to J=46. The line list is computed by variational solution of the Schrodinger equation for the rotation-vibration motion employing the nuclear-motion program TROVE. A previously reported ab initio dipole moment surface is used as well as an updated 'spectroscopic' potential energy surface (PES), obtained by refining an existing ab initio surface through least-squares fitting to the experimentally derived energies. Detailed comparisons with other available sources of phosphine transitions confirms SAlTY's accuracy and illustrates the incompleteness of previous experimental and theoretical compilations for temperatures above 300K. Atmospheric models are expected to severely underestimate the abundance of phosphine in disequilibrium environments, and it is predicted that phosphine will be detectable in the upper troposphere of many substellar objects. This list is suitable for modelling atmospheres of many astrophysical environments, namely carbon stars, Y dwarfs, T dwarfs, hot Jupiters and solar system gas giant planets. It is available in full as supplementary data to the article and at www.exomol.com.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/1469
- Title:
- ExoMol line lists for SiO
- Short Name:
- J/MNRAS/434/1469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate rotation-vibration line lists are calculated for silicon monoxide. Line lists are presented for the main isotopologue, ^28^Si^16^O, and four monosubstituted isotopologues ^29^Si^16^O, ^30^Si^16^O, ^28^Si^17^O and ^28^Si^18^O, in their ground electronic states. These line lists are suitable for high temperatures (up to 9000K) including those relevant to exoplanetary atmospheres and cool stars. A combination of empirical and ab initio methods is used: the potential energy curves are determined to high accuracy by fitting to extensive data from analysis of both laboratory and sunspot spectra; a high quality ab initio dipole moment curve is calculated at the large basis set, multi-reference configuration interaction (MRCI) level. A partition function plus full line lists of rotation-vibration transitions are made available in an electronic form as supplementary data to this article and at www.exomol.com.
- ID:
- ivo://CDS.VizieR/J/A+A/250/370
- Title:
- Far-UV excess object survey
- Short Name:
- J/A+A/250/370
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical spectra have been obtained for a selection of objects included in a catalog of far ultraviolet bright, high galactic latitude objects detected with a balloon-borne survey telescope. The observed objects provide a sample of subdwarf O and B stars, white dwarfs, and binary systems including a hot sub-luminous member. Model atmospheres analysis of the sub-dwarf sample is used to determine the temperature, gravity, and helium to hydrogen ratio of the individual objects. A smooth distribution of objects is found on the gravity versus temperature diagram near the theoretical location of the extended horizontal branch. A break between the helium rich and helium poor objects occurs at 40000K. Suspected binary objects were found and analyzed to determine the temperature and gravity of the hot subluminous member in each system. The number of subdwarf stars contained in binaries is determined to be from 65% to 100%. The number versus ultraviolet magnitude distribution of the subdwarf B sample is modeled to obtain a midplane density of 3.3x10^-6^pc^-3^ and a population scale height of 240pc. The proportion of white dwarfs that experience the subdwarf phase of evolution is found to be 0.94%.
- ID:
- ivo://CDS.VizieR/J/ApJS/202/17
- Title:
- Far-UV spectral atlas of O-type stars
- Short Name:
- J/ApJS/202/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present a spectral atlas covering the wavelength interval 930-1188{AA} for O2-O9.5 stars using Far-Ultraviolet Spectroscopic Explorer archival data. The stars selected for the atlas were drawn from three populations: Galactic main-sequence (classes III-V) stars, supergiants, and main-sequence stars in the Magellanic Clouds, which have low metallicities. For several of these stars, we have prepared FITS files comprised of pairs of merged spectra for user access via the Multimission Archive at Space Telescope (MAST). We chose spectra from the first population with spectral types O4, O5, O6, O7, O8, and O9.5 and used them to compile tables and figures with identifications of all possible atmospheric and interstellar medium lines in the region 949-1188{AA}. Our identified line totals for these six representative spectra are 821 (500), 992 (663), 1077 (749), 1178 (847), 1359 (1001), and 1798 (1392) lines, respectively, where the numbers in parentheses are the totals of lines formed in the atmospheres, according to spectral synthesis models. The total number of unique atmospheric identifications for the six main-sequence O-star template spectra is 1792, whereas the number of atmospheric lines in common to these spectra is 300. The number of identified lines decreases toward earlier types (increasing effective temperature), while the percentages of "missed" features (unknown lines not predicted from our spectral syntheses) drop from a high of 8% at type B0.2, from our recently published B-star far-UV atlas (Cat. J/ApJS/186/175), to 1%-3% for type O spectra. The percentages of overpredicted lines are similar, despite their being much higher for B-star spectra.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/157
- Title:
- Far-UV spectra of Galactic corona sight lines
- Short Name:
- J/ApJ/749/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the properties of the transition temperature (T~10^5^K) gas in the Milky Way corona, based on the measurements of OVI, NV, CIV, SiIV, and FeIII absorption lines seen in the far-ultraviolet spectra of 58 sight lines to extragalactic targets, obtained with the Far-Ultraviolet Spectroscopic Explorer and the Space Telescope Imaging Spectrograph. In many sight lines the Galactic absorption profiles show multiple components, which are analyzed separately. We find that the highly ionized atoms are distributed irregularly in a layer with a scale height of about 3 kpc, which rotates along with the gas in the disk, without an obvious gradient in the rotation velocity away from the Galactic plane. Within this layer the gas has randomly oriented velocities with a dispersion of 40-60km/s. On average the integrated column densities are logN(OVI)=14.3, logN(NV)=13.5, logN(CIV)=14.2, logN(SiIV)=13.6, and logN(FeIII)=14.2, with a dispersion of just 0.2 dex in each case. In sight lines around the Galactic center and Galactic north pole, all column densities are enhanced by a factor ~2, while at intermediate latitudes in the southern sky there is a deficit in N(O VI) of about a factor of two, but no deficit for the other ions.
