Emission Lines Of Ca Research Articles

A Versatile Method for Quantitative Analysis of Total Iron Content in Iron Ore Using Laser-Induced Breakdown Spectroscopy.

Focus in quality assessment of iron ore is the content of total iron (TFe). Laser-induced breakdown spectroscopy (LIBS) technology possesses the merits of rapid, in situ, real-time multielement analysis for iron ore, but its application to quantitative TFe content is subject to interference of the iron matrix effect and the lack of suitable data mining tools. Here, a new method of LIBS-based variable importance back propagation artificial neural network (VI-BP-ANN) for quantitative TFe content in iron ore was first proposed. After the LIBS spectra of 80 representative iron samples were obtained, random forest (RF) was optimized by out-of-bag (OOB) error and then used to measure and rank variable importance. The variable importance thresholds and the number of neurons were optimized with five-fold cross-validation (CV) with correlation coefficient (R2) and root mean square error (RMSE). With using only 1.40% of full spectral variables to construct BP-ANN model, the resulted R2, the root mean squared error of prediction (RMSEP) and the modeling time of the final VI-BP-ANN model was 0.9450, 0.3174 wt%, and 24 s, respectively. Compared with full spectrum-based model, for example, BP-ANN, RF, support vector machine (SVM), and PLS and VI-RF model, the VI-BP-ANN model reduced overfitting and obtained the highest R2 and the lowest RMSE both for calibration and prediction. Meanwhile, the characteristics of variables selected by VI were analyzed. In addition to the elemental emission lines of Ca, Al, Na, K, Mn, Si, Mg, Ti, Zr, and Li, partial spectral baselines of 540-610 nm and 820-970 nm were also selected as characteristic variables, which indicated that VI can take into full consideration the elemental interactions and the spectral baselines. Our approach shows that LIBS combined with VI-BP-ANN is able to quantify TFe content rapidly and accurately in iron ore.

First detection of a disk free of volatile elements around a young A-type star: A possible sign of collisions between rocky planets

Aims. We present the first detailed analysis of the astrophysical parameters of the poorly studied Sco-Cen member HD 152384 and its circumstellar environment. Methods. We analyse newly obtained optical-near-IR X-shooter spectra, as well as archival TESS data, of HD 152384. In addition, we use literature photometric data to construct a detailed spectral energy distribution (SED) of the star. Results. The photospheric absorption lines in the spectrum of HD 152384 are characteristic of an A0 V star, for which we derive a stellar mass of 2.1 ± 0.1 M⊙ and a stellar age > 4.5 Myr. Superimposed on the photospheric absorption, the optical spectrum also displays double-peaked emission lines of Ca II, Fe I, Mg I, and Si I, typical of circumstellar disks. Notably, all hydrogen and helium lines appear strictly in absorption. A toy model shows that the observed emission line profiles can be reproduced by emission from a compact (radius < 0.3 au) disk seen at an inclination of ∼24°. Further evidence for the presence of circumstellar material comes from the detection of a moderate IR excess in the SED, similar to those found in extreme debris disk systems. Conclusions. We conclude that HD 152384 is surrounded by a tenuous circumstellar disk that, although rich in refractory elements, is highly depleted of volatile elements. To the best of our knowledge, such a disk is unique among young stars. However, it is reminiscent of the disks seen in some white dwarfs, which have been attributed to the disruption of rocky planets. We suggest that the disk around HD 152384 may have a similar origin and may be due to collisions in a newly formed planetary system.

Emission spectra of a simulated Chicxulub impact-vapor plume at the Cretaceous–Paleogene boundary

A plume of vaporized sediments and basement rocks was ejected to the top of atmosphere when a 10–15 km asteroid impacted on Yucatan in the Southern Gulf of Mexico about 66 million years ago. The Chicxulub impact-vapor plume emitted a flash of light that had clues on the chemistry and degree of vaporization of the target surface material. Here we simulate the asteroid impact by vaporizing marine carbonate sediments cored in the Yaxcopoil-1 borehole in the Chicxulub crater using an intense infrared laser pulse. We investigate two sedimentary layers that represent the most dominant mineral phases of the target sequence: carbonates and sulfates. Their main constituents are 86% calcite and 74% anhydrite, respectively. The laser-induced vapor plumes were produced from each layer in a background simulated late Cretaceus atmosphere (0.16% CO2, 30% O2, and 69.84% N2). Time-resolved spectroscopic analyses from the laser-induced plumes were carried out using experimental and synthetic spectra. The vapor plumes had similar temperatures (≥7800 K) at 1 μs and their spectra showed similar emissions. The spectra contained the following lines in nm: Ca+ (mostly at 393.4 and 396.9 with less prominence at 370.6 and 373.7), Ca (422.7, 430.3, 443.6, 445.5, 527.0, 560.3, 616.4, and 657.3), N (746.8 and 821.6), O (777.7), and C (794.5). Molecular bands were not conspicuous which indicated complete vaporization of the target material by the laser pulse. The contribution of the granitic basement was examined using synthetic spectra. The expected emissions according to their intensities are: Na (589.6), Ca+ (393.4), Al (396.2, 309.3), Ca+ (396.9), Ca (422.7), Na (819.5) and K (766.5, 769.9). The results suggest that the emission corresponded to Ca+ and Ca originated mostly from the volatilization of the marine sediments, and Na, Al, and K from the basement rocks. The physico-chemical evolution of the Chicxulub impact-vapor plume could be deduced by deciphering the temperature and electron density from the emission lines of Ca and Ca+. These physical parameters can be used in gas dynamic models to predict the fluxes and nature of gases, vapors and mineral phases that were introduced into the atmosphere and better assess their impact to the environment and the biosphere.

Quantitative analysis of saindha salt using laser induced breakdown spectroscopy and cross-validation with ICP-MS

Saindha salt is considered to be more advantageous than the other edible salts for the patients suffering from diabetes, blood pressure and kidney diseases. To explore the constituent elements of this salt, laser induced breakdown spectroscopy (LIBS) has been exploited for its qualitative and quantitative analysis. The third harmonic (355 nm) of a Q-switched Nd:YAG laser has been used to produce the saindha salt plasma and the time integrated optical emission spectra were registered using a set of six miniature spectrometers covering the spectral range of 230–805 nm. The spectroscopic analysis of the emission spectra predominately revealed numerous neutral or singly ionized emission lines of Ca, Mg, Na, K, Fe, Sr, Si, Li and Al. The laser produced plasma was characterized by calculating the electron temperature from the Boltzmann plots and the electron number density from the Stark broadened line profile as a function of laser irradiance and distance from the target sample. The relative concentration of the constituent elements was extracted by the integrated line intensities of the strongest spectral line of each element using the self-calibration-LIBS (SC-LIBS) and one-line calibration free-LIBS (OLCF-LIBS) methods. For cross-validation, the LIBS results have been compared with that obtained from the inductively coupled plasma-mass spectroscopy (ICP-MS) showing good agreement.

The rise and fall of an extraordinary Ca-rich transient

This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kiloparsecs from any likely host. Its light curves rise to maximum light in 5−6 d and then display a decline of Δm15 ∼ 5 mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and “ultra-stripped” type Ic SNe, but the early nebular phase spectra, which were reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10 000–12 000 km s−1. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of 0.2−0.4 M⊙ and a low kinetic energy of (2−4) × 1050 erg, giving a specific kinetic energy Ek/Mej ∼ 1 [1051 erg]/M⊙. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the specific kinetic energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events.

Mineral carbonate dissolution with increasing CO2 pressure measured by underwater laser induced breakdown spectroscopy and its application in carbon sequestration

In this study, the ability of laser-induced breakdown spectroscopy (LIBS) to measure the in situ aqueous dissolution of various mineral carbonates with increasing CO2 pressure was examined. Dissolution experiments included four geologically common mineral carbonates (CaCO3, MgCO3, MnCO3, SrCO3) and the CO2 pressure ranged from ambient to 250 bar. The ensuing plasma emission was spectrally analyzed, and the intensities of Ca, Mg, Mn, and Sr emission lines were used to monitor the respective metal cations released to the aqueous solution. The strong emission lines of Ca (Ca II 393.36, Ca II 396.84, Ca I 422.67 nm), Mg (unresolved magnesium doublet: Mg I 383.230, Mg I 383.829 nm), Mn (unresolved manganese triplet: Mn I 403.076, Mn I 403.307, Mn I 403.449 nm), and Sr (Sr II 407.77, Sr II 421.55, Sr I 460.73 nm) were identified in the spectra. The amounts of metals released from their respective carbonates were estimated at different time intervals following the CO2 injection (5 m, 1, 2, 3, 4, 24 h) and at different pressures (50, 100, 150, 200, 250 bar) using calibration models developed at corresponding pressure settings. The results demonstrated that the pressure-induced dissolution of all carbonates was consistent with their expected and selective pH-dependent solubility. The dissolution rate of CaCO3, MgCO3, and SrCO3 was found to be higher than that of MnCO3. The dissolution of constituents in a Mt. Simon sandstone associated with a deep saline reservoir at elevated CO2 pressure was also studied and Ca release was quantified. The results demonstrated that real-time monitoring of carbonate dissolution by LIBS may provide a useful indirect detection system indicative of CO2 leakage from geologic carbon storage sites.

Emission Spectral Profile of Salt in Laser-Induced Breakdown Spectroscopy (LIBS) on River Clamshell Sample

Since the river clamshell is commonly used as one of the raw materials for making lime betel widely consumed, inspection of its salt content is very important. This work is to study the profile of salt emission spectrum from the river clamshell sample inlaser-induced breakdown spectroscopy (LIBS). The observation of the general emission profile is possible thanking to the availability of the optical multichannel analyzer (OMA) system with a wide wavelength coverage from 200 nm-950 nm. LIBS apparatus used in this work consist of Nd-YAG (neodymium-doped yttrium aluminum garnet) laser and an OMA system equipped with an echelle spectrograph system. The river clamshell samples were collected from Panga River, Panga, Aceh Jaya, Aceh, Indonesia. The Panga river up streams to mountain of Gunong Ujeun, used to an intensive traditional mining location. The plasma generation was made by focusing the Nd-YAG laser beam on the clamshell sample under air surrounding gas at atmospheric pressure. There are two kinds of sample used, namely fresh sample without any treatment and pelletized sample. The result shows the emission spectrum in general consist of a large number of Ca emission lines, both atomic and ionic lines. However, several other salt emission lines such as Mg, Na, K, and Al also can be clearly observed at various wavelengths. This result suggests the emission spectrum of salt detected from the river clam sample are predominantly dominated by Ca emission lines.

Molecular emission in laser-induced breakdown spectroscopy: An investigation of its suitability for chlorine quantification on Mars

The intensity of the molecular CaCl emission in LIBS spectra is examined in order to evaluate its suitability for the detection of chlorine in a Martian environment. Various mixtures resembling Martian targets with varying Cl content are investigated under simulated Martian conditions. The reactions leading to the formation of CaCl are modeled based on reaction kinetics and are used to fit the measured CaCl band intensities. MgCl bands are also investigated as potential alternatives to CaCl, but no MgCl bands can be identified in samples containing both Mg and Cl. The study confirms that CaCl is well suited for the indirect detection of chlorine, but finds a strong dependence on the concentrations of Ca and Cl in the sample. Spectra from samples with a high chlorine concentration can have low-intensity CaCl emission due to a deficiency of Ca. A qualitative estimate of the sample composition is possible based on the ratio of the band intensity of CaCl to the intensity of Ca emission lines. Time-resolved measurements show that the CaCl concentration in the plasma is highest after about 1 µs.

Spectroscopy of Very Hot Plasma in Non-flaring Parts of a Solar Limb Active Region: Spatial and Temporal Properties

Abstract In this work we investigate the thermal structure of an off-limb active region (AR) in various non-flaring areas, as it provides key information on the way these structures are heated. In particular, we concentrate on the very hot component ( > 3 MK ) as it is a crucial element to distinguish between different heating mechanisms. We present an analysis using Fe and Ca emission lines from both the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory (SOHO) and the EUV Imaging Spectrometer (EIS) on board Hinode. A data set covering all ionization stages from Fe x to Fe xix has been used for the thermal analysis (both differential emission measure and emission measure, EM). Ca xiv is used for the SUMER-EIS radiometric cross calibration. We show that the very hot plasma is present and persistent almost everywhere in the core of the limb AR. The off-limb AR is clearly structured in Fe xviii. Almost everywhere, the EM analysis reveals plasma at 10 MK (visible in Fe xix emission), which is down to 0.1% of EM of the main 3 MK plasma. We estimate the power-law index of the hot tail of the EM to be between −8.5 and −4.4. However, the question about the possible existence of a small minor peak at around 10 MK remains open. The absence in some part of the AR of the Fe xix and Fe xxiii lines (which fall into our spectral range) enables us to determine an upper limit on the EM at these temperatures. Our results include a new Ca xiv 943.59 Å atomic model.

Note: Liquid chemical sensing by emission spectroscopy with a nanosecond pin-hole discharge in water.

This paper presents a simple yet effective method for chemical detection by emission spectroscopy using a nanosecond pin-hole discharge in water. The discharge was produced in a 200-μm-diameter microchannel in water without electrode contact. The simultaneous detection of multiple mineral ions was demonstrated by measuring the intensity of Na and Ca emission lines at different concentrations. The device can be further scaled down to be integrated with microfluidic systems for monitoring water contamination or hazardous materials in other aqueous solutions.

Laser-Induced Breakdown Spectroscopy (LIBS) of Heavy Metal Ions at the Sub-Parts per Million Level in Water

We report a simple sub parts per million (sub-ppm) detection method for heavy metals in water by laser-induced breakdown spectroscopy (LIBS). Filter papers were used as the substrates for both transforming aqueous solutions to solid samples and for pre-concentrating dissolved heavy metal ions. The amount of sample uptake was 1.2 g by soaking a filter paper. This provides limit-of-detection (LOD) values of 2.7 and 0.36 ppm for Pb and Cr, respectively. The LODs could be improved remarkably by pre-concentrating the heavy metal ions. When a 40 g sample solution was evaporated on a filter paper, the LODs of 75 and 18 parts per billion (ppb) were obtained for Pb and Cr, respectively. Moreover, by either increasing the evaporated amount of sample solution or applying an argon gas flow, further improvement of the LODs was found to be very promising. The LIBS spectra of tap water were recorded using the pre-concentration method and are discussed in comparison with the results from inductively coupled plasma atomic emission spectroscopy (ICP-AES). We could observe strong emission lines of Ca, Mg, K, Cu, and Sr in the tap water, of which concentrations were determined to be 6.3, 1.3, 1.1, 0.64, and 0.046 ppm, respectively, by ICP-AES. Our method shows promise as a fast, reliable, water-quality monitoring tool for heavy-metal concentrations as well as for hardness.

Determination of Ca content of coral skeleton by analyte additive method using the LIBS technique

Laser-induced breakdown spectroscopic (LIBS) technique was used to study the elemental profile of coral skeletons. Apart from calcium and carbon, which are the main elemental constituents of coral skeleton, elements like Sr, Na, Mg, Li, Si, Cu, Ti, K, Mn, Zn, Ba, Mo, Br and Fe were detected in the coral skeletons from the Inani Beach and the Saint Martin’s island of Bangladesh and the coral from the Philippines. In addition to the qualitative analysis, the quantitative analysis of the main elemental constituent, calcium (Ca), was done. The result shows the presence of (36.15±1.43)% by weight of Ca in the coral skeleton collected from the Inani Beach, Cox’s Bazar, Bangladesh. It was determined by using six calibration curves, drawn for six emission lines of Ca I (428.301nm, 428.936nm, 431.865nm, 443.544nm, 443.569nm, and 445.589nm), by standard analyte additive method. Also from AAS measurement the percentage content of Ca in the same sample of coral skeleton obtained was 39.87% by weight which compares fairly well with the result obtained by the analyte additive method.

In vitro assessment of chelating agents with regard to their abstraction efficiency of Cd2+ bound to plasma proteins

The exposure of various human populations to Cd(2+) is of increasing health concern. After its gastrointestinal absorption into the bloodstream, Cd(2+) binds to α(2)-macroglobulin and serum albumin. Although animal studies have demonstrated that meso-2,3-dimercaptosuccinic acid (DMSA) and diethylenetriamine pentaacetic acid (DTPA) can effectively mobilize Cd(2+) to urine and decrease the Cd concentrations of the kidneys, the liver and the brain, not much is known about the abstraction of Cd(2+) from blood plasma proteins. We prepared a stock of Cd(2+) spiked rabbit plasma (2.0 μg of Cd(2+)/mL) and analyzed aliquots by size exclusion chromatography coupled on-line to an inductively coupled plasma atomic emission spectrometer (SEC-ICP-AES) while simultaneously monitoring the emission lines of Ca, Cd, Cu, Fe, and Zn. After the addition of 0.33 mM, 0.66 mM or 0.99 mM of DMSA, DTPA, 2,3-dimercapto-1-propanesulfonic acid (DMPS) or N-acetyl-l-cysteine (NAC) to plasma aliquots, the obtained mixtures were analyzed by SEC-ICP-AES after 5 min and 30 min. None of the investigated compounds adversely affected the plasma distribution of Fe at all investigated doses. At 0.33 mM, DTPA was most effective at mobilizing plasma protein bound Cd(2+) to a ~5 kDa Cd-species (100% removal), followed by DMPS (94%), DMSA (83%) and NAC (3%). All investigated compounds also mobilized Zn(2+) from plasma proteins to ~5 kDa Zn-species (DTPA: 80% removal; DMPS: 63%; DMSA: 29% and NAC: 3%). The addition of DTPA resulted in the dose-dependent elution of a [Ca-DTPA](3-) complex. Based on these results, 0.33 mM DMSA represents the best compromise that can be achieved between maximizing the abstraction of Cd(2+) from plasma proteins (83%), while minimizing the mobilization of Zn(2+) from plasma proteins (29%), and avoiding the complexation of Ca(2+).

Size-resolved analysis of fine and ultrafine particulate matter by laser-induced breakdown spectroscopy

In emissions originating from industrial processes, elemental concentration characteristically depends on particle size. Therefore, not only is the average chemical composition of the particles in the focus of interest but also their size-dependent composition. For industrial applications such as on-line process control, a system using laser-induced breakdown spectroscopy (LIBS) is developed providing the analysis of particulate matter directly in an air stream with a short response time to changes in elemental composition. By using a co-flow in addition to the aersosol flow the time resolution of the system can be enhanced. Investigations are undertaken concerning properties of the laser plasma, the analysis of monodisperse and polydisperse aerosols with regard to the relative elemental concentration and the mass concentration of the particles. The system can be calibrated to either total elemental concentrations or relative compositions. The signal response to a variation of elemental concentration as well as to the particle mass concentration show kinds of saturation effects. Temporal plasma evolution for CaCl2 particles and pure argon are investigated. Different decay times for argon and the particle matter depending on the origin of lines within the plasma are observed. Electron density and temperature are determined using Ca emission lines to describe the temporal evolution of the plasma state for the particle analysis. It has been observed that the electron density increases rapidly for plasma temperatures above 10 000 K. Size-resolved analyses of particles in the size range from 20 nm up to 800 nm are carried out. It has been found that the signal response correlates with the mass distribution of the particles.

Quenching of He-induced intensity enhancement effect in H and D emission produced by Nd-doped yttrium aluminum garnet laser irradiation on solid targets in low pressure helium gas

An experimental study was performed on the N2-induced quenching of He-induced intensity enhancement effect in reduced-pressure plasma emission produced by Nd-YAG irradiation on solid zircaloy and porous fossil samples. The spatial distributions and temporal variations in the emission intensities show pronounced intensity quenching effects on the He I 667.9 nm, H I 656.2 nm, and D I 656.1 nm emission lines in both samples when a tiny amount (5% by volume) of nitrogen was added to helium gas, while leaving the spatial and temporal intensity profiles of the heavier Zr and Ca atoms virtually unaffected. In both cases of different ambient gases, the spatial and temporal variations in the He, H, and D emission intensities exhibit distinct features and changes, which are clearly distinguishable from those observed on the Zr and Ca emission lines, which were mainly produced by the shock-wave induced thermal excitation process. The analysis of these data unambiguously revealed the presence of an additional and distinct “He-assisted” excitation mechanism in the He plasma, which was further suggested to be related to the He metastable excited state. The quenching effect was therefore explained as a consequence of energy depletion of the He metastable excited state triggered by the Penning ionization process induced by the presence of nitrogen. This also explains the relatively insensitive response of the Zr and Ca emission intensity profiles to nitrogen addition despite the increased plasma electron density resulting from the ionization process.

Meteor luminosity simulation through laser ablation of meteorites

Abstract Light production mechanisms during ablation of meteors in planetary atmospheres are still not well understood. We have used a high-power pulsed (15 mJ per 10-ns pulse) Nd:YAG laser, frequency-doubled to 532-nm wavelength, to heat chondritic meteorite samples rapidly, and then used CCD imaging and spectral cameras to search for light produced by the rapidly heated meteorite vapour. We report here that light is produced by the rapidly heated and expanding ablated material without the need for collision with a high-speed atomic beam. The light production region is of the order of 2 mm in diameter. The light produced is a combination of either continuum or unresolved spectral line emission, along with spectral emission lines of Ca, Fe, Na, N, Mg, Si and O, with spectra from both neutral and singly ionized species. We have used a scanning electron microscope (SEM) to characterize the size of the ablated region (approximately 160 μm wide and 170 μm deep). The SEM, equipped with energy-dispersive X-ray spectroscopy, was also used to perform elemental analysis of our sample, which confirmed the presence of the identified elements in the original meteorite. The current experiments were done at room temperature and pressure, with mean power input rates that would correspond to low atmospheric penetration of meteorites. While others have used similar techniques for remote identification of elements present on surfaces in space and in meteorites, to our knowledge this is the first paper to propose laser ablation as a means of studying light production in modest-sized meteors.

Application of the laser ablation for conservation of historical paper documents

Laser ablation was applied for surface cleaning and spectroscopic diagnostics of historical paper documents and model samples in the framework of the conservation projects. During cleaning the spectra of ablation products were recorded by means of the LIBS technique which allowed for nearly non-destructive identification of surface layers such as contaminants, substrate and pigments. For consecutive laser pulses a strong decrease of band intensities of the emission lines of Ca, Na, K, Al and Fe ascribed to contaminants were observed. The effect was used for monitoring of the cleaning progress of stained paper. For surface cleaning and spectra excitation the Q-switched Nd:YAG laser of 6 ns pulsewidth operating at wavelengths of 266, 355, 532, and 1064 nm and of fluence selected from the range 0.3–0.9 J/cm 2 was applied. The ablation parameters were optimized in agreement with the literature and the results were confirmed by surface studies and testing of the mechanical and chemical properties, and also by the response to the ageing process of the paper substrate. In case of the model paper irradiated in the UV range at 266 and 355 nm a visual inspection revealed local damages of the cellulose fibers accompanied by a decrease of the mechanical strength of the substrate. The effect was more pronounced after artificial ageing. The best results were obtained for samples irradiated at 532 nm and at laser fluence below the damage threshold of 0.6 J/cm 2, which is in agreement with literature.

M33's Variable A: A Hypergiant Star More Than 35 YEARS in Eruption

Variable A in M33 is a member of a rare class of highly luminous, evolved stars near the upper luminosity boundary that show sudden and dramatic shifts in apparent temperature due to the formation of optically thick winds in high mass loss episodes. Recent optical and infrared spectroscopy and imaging reveal that its eruption, begun in ~1950, has ended, having lasted ≈45 yr. Our current observations show major changes in its wind from a cool, dense envelope to a much warmer state surrounded by low-density gas with rare emission lines of Ca II, [Ca II], and K I. Its spectral energy distribution has unexpectedly changed, especially at the long wavelengths, with a significant decrease in its apparent flux, while the star remains optically obscured. We conclude that much of its radiation is now escaping out of our line of sight. We attribute this to the changing structure and distribution of its circumstellar ejecta, corresponding to the altered state of its wind as the star recovers from a high mass loss event.

The near-infrared spectra of low-mass X-ray binaries and related objects

view Abstract Citations (24) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Near-Infrared Spectra of Low-Mass X-Ray Binaries and Related Objects Cowley, A. P. ; Schmidtke, P. C. ; Crampton, D. ; Hutchings, J. B. ; Bolte, M. Abstract Spectra in the region of the Ca II infrared triplet (about 8300-8900 A) have been obtained for a number of low-mass X-ray binaries (LMXB) and a small sample of other cataclysmic variables. The secondary (mass-losing) star is detected strongly in only a small number of systems, indicating that the accretion disks normally contribute the majority of the flux even at these wavelengths. Emission lines of Ca II and/or H are present in some of these binaries. New photometry is presented for many of these systems. Publication: The Astrophysical Journal Pub Date: May 1991 DOI: 10.1086/170041 Bibcode: 1991ApJ...373..228C Keywords: Accretion Disks; Dwarf Novae; Infrared Spectra; Neutron Stars; Stellar Spectra; X Ray Binaries; Astronomical Photometry; Calcium; Cataclysmic Variables; Emission Spectra; Line Spectra; Near Infrared Radiation; Astrophysics; STARS: ACCRETION; STARS: DWARF NOVAE; STARS: EMISSION-LINE; STARS: NEUTRON; X-RAYS: BINARIES full text sources ADS | data products SIMBAD (20)

Laser Breakdown Spectrochemical Analysis of Microparticles in Liquids

Abstract A focused pulsed laser beam was irradiated on a CaCO3 microparticle in water, and a laser breakdown of single microparticle was induced. In the laser breakdown plasma emission spectrum, the emission lines of Ca I and Ca II were observed, while these lines did not appear for the Ca2+ aqueous solution. Hence this method is effective for analysis of microparticulate impurities in liquids.