- ID:
- ivo://CDS.VizieR/J/AJ/135/2245
- Title:
- Absolute spectrum of the Sun and Vega for 0.2-30um
- Short Name:
- J/AJ/135/2245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine an absolute calibration for the Multiband Imaging Photometer for Spitzer 24um band and recommend adjustments to the published calibrations for Two Micron All Sky Survey (2MASS), Infrared Array Camera (IRAC), and IRAS photometry to put them on the same scale. We show that consistent results are obtained by basing the calibration on either an average A0V star spectral energy distribution (SED), or by using the absolutely calibrated SED of the Sun in comparison with solar-type stellar photometry (the solar analog method).
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- ID:
- ivo://CDS.VizieR/J/A+A/589/A17
- Title:
- Abundance analysis of solar twin HIP 100963
- Short Name:
- J/A+A/589/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze and investigate the origin of the abundance pattern of HIP 100963 in detail, in particular the pattern of the light element Li, the volatile and refractory elements, and heavy elements from the s- and r-processes. We confirm that HIP 100963 is a solar twin and demonstrate that its abundance pattern is about solar after corrections for GCE. The star also shows enrichment in s- and r-process elements, as well as depletion in lithium that is caused by stellar evolution.
- ID:
- ivo://CDS.VizieR/J/AZh/75/586
- Title:
- Abundances in solar atmosphere
- Short Name:
- J/AZh/75/586
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An analysis of the chemical composition of the solar atmosphere is performed using spectrograms of the daylight sky obtained on the ZTS telescope (dispersion 3{AA}/mm, signal-to-noise ration, S/N>100). The chemical composition derived in the framework of a Holweger-Muller atmosphere model are in excellent agreement with the generally accepted values. Analysis based on the models of Bell et al. (1976A&AS...23...37B) and Kurucz (1992RMxAA..23..181K) with Teff=5770K and logg=4.44 failed to give satisfactory results.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/123
- Title:
- Abundances of heavy ions in ICMEs from 1998-2011
- Short Name:
- J/ApJ/900/123
- Date:
- 20 Jan 2022 00:43:36
- Publisher:
- CDS
- Description:
- This statistical work studies the abundances and the charge states of the carbon, oxygen, and iron ions in 281 interplanetary coronal mass ejections (ICMEs) measured at 1 au by ACE spacecraft from 1998 to 2011. The Gaussian distribution test is applied, and the analysis of variance is used to quantify the similarity between two distributions of ionic charge states and abundances. The correlation coefficient is calculated to reveal the dependence of the abundances and the mean charge of heavy ions on the solar activity. The results show that the mean charge, the abundance, and the speed at 1 au are highly related to the sunspot number (SN). The O7+/O6+ shows statistical difference between the high speed and the low speed groups of ICMEs. Different from the cold materials inside ICMEs, the mean charge of carbon ions shows a positive relation to that of oxygen ions. The Mg/O in the studied ICMEs are much higher than that in the solar wind. Three types of charge distribution of C, O, and Fe ions are summarized. The fraction of each of the three types is related to the solar minimum or the solar maximum. The mean charge and the flux of oxygen ions show quasi-linear relations to the SN during solar minimum, and show fluctuations during maximum. The results reveal that the solar activity, which represents the solar magnetic field status by nature, controls the composition of heavy ions in ICMEs.
- ID:
- ivo://CDS.VizieR/J/ApJS/183/225
- Title:
- A catalog of coronal "EIT wave" transients
- Short Name:
- J/ApJS/183/225
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT) data have been visually searched for coronal "EIT wave" transients over the period beginning from 1997 March 24 and extending through 1998 June 24. The dates covered start at the beginning of regular high-cadence (more than 1 image every 20 minutes) observations, ending at the four-month interruption of SOHO observations in mid-1998. One hundred and seventy six events are included in this catalog. The observations range from "candidate" events, which were either weak or had insufficient data coverage, to events which were well defined and were clearly distinguishable in the data. Included in the catalog are times of the EIT images in which the events are observed, diagrams indicating the observed locations of the wave fronts and associated active regions, and the speeds of the wave fronts. The measured speeds of the wave fronts varied from less than 50 to over 700km/s with "typical" speeds of 200-400km/s.
- ID:
- ivo://CDS.VizieR/J/A+AS/131/431
- Title:
- Accurate wavelengths in the Sun spectrum
- Short Name:
- J/A+AS/131/431
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Central line wavelengths in the spectrum of the Sun observed at the centre of the disc, and in the flux spectrum, line identification and solar log(gf).
- ID:
- ivo://CDS.VizieR/J/AJ/138/312
- Title:
- Activity of bright solar analogs
- Short Name:
- J/AJ/138/312
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 14 years of contemporaneous photometric and spectroscopic observations of 28 solar analog stars, taken with the Tennessee State University Automatic Photometric Telescopes at Fairborn Observatory and the Solar-Stellar Spectrograph at Lowell Observatory. These are the best observed and most nearly Sun-like of the targets in our magnitude-limited (V<=7.5) sample. The correlations between luminosity and activity reveal the expected inverse activity-brightness correlations for active stars. Strong direct correlations between activity and brightness are not prevalent for the less active solar age stars, but are precision limited.
- ID:
- ivo://CDS.VizieR/J/A+A/560/A61
- Title:
- A frequency Comb calibrated solar atlas
- Short Name:
- J/A+A/560/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The solar spectrum is a primary reference for the study of physical processes in stars and their variation during activity cycles. High resolution spectra of the Sun are easily obtained from spatially selected regions of the solar disk, while those taken over the integrated disk are more problematic. However, a proxy can be obtained by using solar light reflected by small bodies of the solar system. We first apply the LFC solar spectrum to characterize the CCDs of the HARPS spectrograph. The comparison of the LFC and Th-Ar calibrated spectra reveals S-type distortions on each order along the whole spectral range with an amplitude of 40m/s. This confirms the pattern found by Wilken et al. (2010MNRAS.405L..16W) on a single order and extends the detection of the distortions to the whole analyzed region revealing that the precise shape varies with wavelength. A new data reduction is implemented to deal with CCD pixel inequalities to obtain a wavelength corrected solar spectrum. By using this spectrum we provide a new LFC calibrated solar atlas with 400 line positions in the range of 476-530, and 175 lines in the 534-585nm range corresponding to the LFC bandwidth. The new LFC atlas is consistent on average with that based on FTS solar spectra, but it improves the accuracy of individual lines by a significant factor reaching a mean value of 10m/s. The LFC-based solar line wavelengths are essentially free of major instrumental effects and provide a reference for absolute solar line positions at the date of Nov 2010, i.e. an epoch of low solar activity. We suggest that future LFC observations could be used to trace small radial velocity changes of the whole solar photospheric spectrum in connection with the solar cycle and for direct comparison with the predicted line positions of 3D radiative hydrodynamical models of the solar photosphere. The LFC calibrated solar atlas can be also used to verify the accuracy of ground or space spectrographs by means of the solar spectrum.
- ID:
- ivo://CDS.VizieR/J/A+A/432/1063
- Title:
- Analysis of inner solar corona in Extreme-UV
- Short Name:
- J/A+A/432/1063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the differential emission measure (DEM) of a `quiet Sun' area observed in the extreme ultraviolet at normal incidence by the Coronal Diagnostic Spectrometer (CDS) on the SOHO spacecraft. The data used for this work were taken using the NISAT_S_ observing sequence. This takes the full wavelength ranges from both the NIS channels (308-381{AA} and 513-633{AA}) with the 2 arcsec by 240 arcsec slit, which is the narrowest slit available, yielding the best spectral resolution. In this work we contrast the DEM from subregions of 2*80arcsec^2^ with that obtained from the mean spectrum of the whole raster (20*240arcsec^2^). We find that the DEM maintains essentially the same shape in the subregions, differing by a constant factor between 0.5 and 2 from the mean DEM, except in areas were the electron density is below 2*10^7^cm^-3^ and downflow velocities of 50km/s are found in the transition region. Such areas are likely to contain plasma departing from ionisation equilibrium, violating the basic assumptions underlying the DEM method. The comparison between lines of Li-like and Be-like ions may provide further evidence of departure from ionisation equilibrium. We find also that line intensities tend to be lower where velocities of the order of 30km/s or higher are measured in transition region lines. The DEM analysis is also exploited to improve the line identification performed by Brooks et al. (1999A&A...347..277B) and to investigate possible elemental abundance variations from region to region. We find that the plasma has composition close to photospheric in all the subregions examined.
- ID:
- ivo://CDS.VizieR/J/A+AS/132/195
- Title:
- Astrolabe observations of the Sun in 1995-1997
- Short Name:
- J/A+AS/132/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the Sun with a modified Danjon astrolabe at 30{deg} and 60{deg} zenith distances have been carried out since 1990 at Santiago, Chile. Here are presented the results in right ascension, parameter Y and apparent semidiameter obtained during the period 1995-1997. These results and those obtained in for mer years are available in electronic form. The differences astrolabe minus ephemeris in {alpha} and semidiameter are briefly discussed.
