J/ApJ/855/134ivo://CDS.VizieR/J/ApJ/855/134doi:10.26093/cds/vizier.18550134CDSJaeggli S.A.Judge P.G.Daw A.N.2019-03-20T08:38:27Z2019-02-18T14:56:47ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frastronomical-modelsstellar-atmospheresthe-sunspectroscopyultraviolet-astronomymolecular-physicsUltraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650km in standard one-dimensional (1D) models of the quiet Sun, near the {tau}=1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550{AA} is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.2018ApJ...855..134Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/855/134CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+AS/141/297 : H_2_ total transition probability (Abgrall+, 2000)J/A+A/375/591 : SUMER Spectral Atlas of Solar Disk Features (Curdt+, 2001)J/A+A/588/A96 : Partition functions for molecules and atoms (Barklem+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/855/134https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/855/134http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/855/134https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/855/134https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/855/134http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/855/134GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVdefaultJ/ApJ/855/134/fig5*Synthetic H2 fluorescence spectra generated with the FALC, COX, and F2 atmospheresrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[910/1800] Wavelength; Angstroms0.1nmem.wldoublei01[3.4/182300] Spectral intensity from FALCx1cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei02[3.8/444600] Spectral intensity from FALCx3cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei03[4.9/1.4e+06] Spectral intensity from FALCx10cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei04[8.7/2.2e+06] Spectral intensity from FALCx30cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei05[16/7.3e+06] Spectral intensity from FALCx100cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei06[0.1/142200] Spectral intensity from COXx1cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei07[0.2/417400] Spectral intensity from COXx3cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei08[0.5/1.4e+06] Spectral intensity from COXx10cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei09[1.2/2.2e+06] Spectral intensity from COXx30cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei10[2.2/7.3e+06] Spectral intensity from COXx100cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei11[2501/6.3e+07] Spectral intensity from F2x1cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei12[2501/6.4e+07] Spectral intensity from F2x3cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei13[2503/6.4e+07] Spectral intensity from F2x10cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei14[2508/6.5e+07] Spectral intensity from F2x30cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoublei15[2524/7e+07] Spectral intensity from F2x100cutoff (1)cW.m**-2.nm**-1.sr**-1spect.line.intensitydoubleJ/ApJ/855/134/dataParameters for lines of the H2 Lyman and Werner band and H2 line-integrated intensities and primary excitation for each of the model scenarios (datafileA and B)cjUpper level configurationphys.atmol.configurationcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWave[844.8/1844.6] Wavelength; Angstroms0.1nmem.wl;phys.atmol.transitiondoubleJi[0/26] Lower level angular momentum quantum numberphys.atmol.qnintvi[0/14] Lower level vibrational quantum numberphys.atmol.qn;phys.mol.vibrationintci[X] Lower level configurationphys.atmol.configurationcharEi[0/36105] Lower level energycm**-1phys.energy;phys.atmol.leveldoubleJj[0/25] Upper level angular momentum quantum numberphys.atmol.qnintvj[0/37] Upper level vibrational quantum numberphys.atmol.qn;phys.mol.vibrationintEj[90203/118376] Upper level energycm**-1phys.energy;phys.atmol.leveldoubleAji[1e-06/6.2e+08] Einstein coefficient for spontaneous emissions**-1phys.atmol.transProbdoublePB[0.004/1] Probability upper level decays to a bound statestat.probability;phys.atmol.levelfloatil01[0/242.3] Line intensity from FALCx1cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp01[1103.2/1520] Wavelength of primary pump from FALCx1cutoff0.1nmem.wl;phys.atmol.transitiondoubleil02[0/242.6] Line intensity from FALCx3cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp02[977/1520] Wavelength of primary pump from FALCx3cutoff0.1nmem.wl;phys.atmol.transitiondoubleil03[0/243.6] Line intensity from FALCx10cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp03[976.8/1520] Wavelength of primary pump from FALCx10cutoff0.1nmem.wl;phys.atmol.transitiondoubleil04[0/248.2] Line intensity from FALCx30cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp04[976.6/1520] Wavelength of primary pump from FALCx30cutoff0.1nmem.wl;phys.atmol.transitiondoubleil05[0/266.2] Line intensity from FALCx100cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp05[919.8/1520] Wavelength of primary pump from FALCx100cutoff0.1nmem.wl;phys.atmol.transitiondoubleil06[0/274.6] Line intensity from COXx1cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp06[912/1518.2] Wavelength of primary pump from COXx1cutoff0.1nmem.wl;phys.atmol.transitiondoubleil07[0/274.2] Line intensity from COXx3cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp07[912/1518.2] Wavelength of primary pump from COXx3cutoff0.1nmem.wl;phys.atmol.transitiondoubleil08[0/274.3] Line intensity from COXx10cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp08[912/1520] Wavelength of primary pump from COXx10cutoff0.1nmem.wl;phys.atmol.transitiondoubleil09[0/276.7] Line intensity from COXx30cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp09[912/1520] Wavelength of primary pump from COXx30cutoff0.1nmem.wl;phys.atmol.transitiondoubleil10[0/449.6] Line intensity from COXx100cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp10[912/1515] Wavelength of primary pump from COXx100cutoff0.1nmem.wl;phys.atmol.transitiondoubleil11[0/4841] Line intensity from F2x1cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp11[1103.2/1520] Wavelength of primary pump from F2x1cutoff0.1nmem.wl;phys.atmol.transitiondoubleil12[0/4841] Line intensity from F2x3cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp12[1103.2/1520] Wavelength of primary pump from F2x3cutoff0.1nmem.wl;phys.atmol.transitiondoubleil13[0/4842] Line intensity from F2x10cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp13[1103.2/1520] Wavelength of primary pump from F2x10cutoff0.1nmem.wl;phys.atmol.transitiondoubleil14[0/4845] Line intensity from F2x30cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp14[1103.2/1520] Wavelength of primary pump from F2x30cutoff0.1nmem.wl;phys.atmol.transitiondoubleil15[0/4856] Line intensity from F2x100cutoff (1)mW.m**-2.sr**-1spect.line.intensitydoublewp15[1103.2/1520] Wavelength of primary pump from F2x100cutoff0.1nmem.wl;phys.atmol.transitiondouble