High-resolution Near-infrared Spectra Research Articles

High Spectral Resolution Observations of the Massive Stars in the Galactic Center

We present high-resolution near-infrared spectra, obtained with the NIRSPEC spectrograph on the W. M. Keck II Telescope, of a collection of hot, massive stars within the central 25'' of the Galactic center. We have identified a total of 21 emission-line stars, seven of which are new radial velocity detections, with five of those being classified as He I emission-line stars for the first time. These stars fall into two categories based on their spectral properties: (1) those with narrow 2.112, 2.113 μm He I doublet absorption lines, and (2) those with broad 2.058 μm He I emission lines. These data have the highest spectral resolution ever obtained for these sources and, as a result, both components of the absorption doublet are separately resolved for the first time. We use these spectral features to measure radial velocities. The majority of the measured radial velocities have relative errors of 20 km s-1, smaller than those previously obtained with proper-motion or radial velocity measurements for similar stellar samples in the Galactic center. The radial velocities estimated from the He I absorption doublet are more robust than those previously estimated from the 2.058 μm emission line, since they do not suffer from confusion due to emission from the surrounding ISM. Using this velocity information, we agree with previous stellar velocity studies that the stars are orbiting in a somewhat coherent manner but are not as defined into a disk or disks as previously thought. Finally, multiepoch radial velocity measurements for IRS 16NE show a change in its velocity, presumably due to an unseen stellar companion.

Evaluation of Nonstarch Polysaccharides and Oligosaccharide Content of Different Soybean Varieties (Glycine max) by Near-Infrared Spectroscopy and Proteomics

A total of 832 samples of soybeans were screened by near-infrared (NIR) reflectance spectroscopy, to identify soybean samples with a lower content of oligosaccharides and nonstarch polysaccharides (NSP). Of these, 38 samples were identified on the basis of variation in protein content and agronomic value and submitted to high-resolution NIR spectroscopy. On the basis of the NIR data, 12 samples were further selected for chromatographic characterization of carbohydrate composition (mono-, di-, and oligosaccharides and NSP). Their soluble proteins were separated by two-dimensional gel electrophoresis (2DE). Using partial least-squares regression (PLSR), it was possible to predict the content of total NSP from the high-resolution NIR spectra, suggesting that NIR is a suitable and rapid nondestructive method to determine carbohydrate composition in soybeans. The 2DE analyses showed varying intensities of several proteins, including the glycinin G1 precursor. PLSR analysis showed a negative correlation between this protein and insoluble NSP and total uronic acid (UA).

Automated high-resolution frequency-stabilized cavity ring-down absorption spectrometer

We describe a frequency-stabilized cavity ring-down absorption spectrometer with automated scanning capabilities. The system utilizes the comb of ring-down cavity resonances as frequency markers for spectral scans. The comb is actively stabilized with respect to a frequency-stabilized reference laser, and the continuous wave, single-mode probe laser frequency is in turn actively stabilized with respect to resonances of the ring-down cavity frequency comb. Ring-down spectra are obtained by locking the external-cavity diode laser probe to sequential cavity resonances (separated by the ring-down cavity free spectral range), and the ring-down cavity frequency comb is translated by controlled amounts using acousto-optic frequency shifting methods for fine frequency steps less than the free-spectral range. A computer-controlled method for automating frequency tuning and probe laser locking to the cavity resonances is described, and high-resolution near-infrared (vicinity of 10712cm−1) absorption spectra of water vapor are presented. A frequency resolution of ≈1MHz and minimum measurable line intensity of 10−27cm2cm−1molecule−1 are demonstrated.

Dynamical Masses of the Binary Brown Dwarf GJ 569 Bab

We have obtained new images and high-resolution (R ~ 22,400) near-infrared (1.2400-1.2575 μm) spectra of each component of the brown dwarf binary GJ 569 Bab using the adaptive optics facility of the Keck II telescope and the NIRSPEC spectrometer. These data have allowed us to improve the determination of the astrometric orbit and to measure radial velocities of the components. We have used the astrometric and spectroscopic measurements to derive the dynamical mass of each brown dwarf and the systemic velocity of the pair by means of a χ2 fitting technique. From various considerations, the mass of each component is likely in the range 0.034-0.070 M☉ (GJ 569 Bb) and 0.055-0.087 M☉ (GJ 569 Ba). This implies that the mass ratio q of the binary is greater than 0.4, the most likely value being q = 0.75-0.85. Adopting 0.072 M☉ as the most conservative location of the substellar limit for solar metallicity, our analysis confirms GJ 569 Bb as the first genuine brown dwarf known without any theoretical assumptions. We have compared the dynamical masses of GJ 569 Ba and Bb, and their effective temperatures and luminosities, to the predictions of state-of-the-art theoretical evolutionary isochrones, finding that models exhibit good performance in the regime of high substellar masses if the binary is about a few hundred million years old. However, the surface gravities of GJ 569 Ba (M8.5 V) and Bb (M9 V) derived from our spectral analysis (the observed data have been compared to the latest synthetic spectra) appear to be smaller than the values provided by the evolutionary models.

Near infrared spectroscopy of carbon dioxide. II: 16O 13C 16O and 16O 13C 18O line positions

High-resolution near-infrared (4000–8500 cm −1) spectra of 13C-enriched carbon dioxide have been recorded using the McMath-Pierce Fourier transform spectrometer at the Kitt Peak National Solar Observatory. We observed over 1000 line positions for the 16O 13C 16O isotopologue, the majority of which have previously been observed only in spectra of the Venusian atmosphere [J. Mol. Spectrosc. 67 (1977) 304]. These have been analyzed to determine spectroscopic constants for 28 different vibrational states. The analysis yielded RMS fitting residuals <1.5 × 10 −4 cm −1 for the strongest bands and RMS residuals <5 × 10 −4 cm −1 for most other fitted bands. A 5% 18O-enrichment in the sample enabled us to observe 410 line positions from 5 near-infrared vibrational bands of the 16O 13C 18O isotopologue. Analysis of the 16O 13C 18O bands yielded RMS fitting residuals <2 × 10 −4 cm −1. Additionally, the first fits for the 16O 13C 18O 11101 ← 01101 and 11102 ← 01101 hot bands yielded RMS residuals of 2.3 × 10 −4 and 2.2 × 10 −4 cm −1, respectively. Critical reevaluations of the spectroscopic constants for the low lying vibrational states for both isotopologues have been performed as part of the analysis.

Metallicity in the Galactic Center: The Arches Cluster

We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties and, most importantly, metallicity content. The analysis uses a new technique, presented here for the first time, and uses line-blanketed NLTE wind/atmosphere models fit to high-resolution near-infrared spectra of late-type nitrogen-rich Wolf-Rayet stars and OfI+ stars in the cluster. It relies on the fact that massive stars reach a maximum nitrogen abundance that is related to initial metallicity when they are in the WNL phase. We determine the present-day nitrogen abundance of the WNL stars in the Arches cluster to be 1.6% (mass fraction) and constrain the stellar metallicity in the cluster to be solar. This result is invariant to assumptions about the mass-luminosity relationship, the mass-loss rates, and rotation speeds. In addition, from this analysis, we find the age of the Arches cluster to be 2-2.5Myr, assuming coeval formation.

Near infrared spectroscopy of carbon dioxide I. 16O 12C 16O line positions

High-resolution near-infrared (4000–9000 cm −1) spectra of carbon dioxide have been recorded using the McMath–Pierce Fourier transform spectrometer at the Kitt Peak National Solar Observatory. Some 2500 observed positions have been used to determine spectroscopic constants for 53 different vibrational states of the 16O 12C 16O isotopologue, including eight vibrational states for which laboratory spectra have not previously been reported. Calibration by simultaneous use of CO near 4200 cm −1 and C 2H 2 near 6500 cm −1 provides absolute line position accuracies of 6.0 × 10 −5 cm −1 (RMS) for strong, isolated transitions throughout the observed range. Fits with RMS errors <3.8 × 10 −5 cm −1 have been obtained for the 20013 ← 00001, 20012 ← 00001, and 20011 ← 00001 bands, RMS errors <6 × 10 −5 cm −1 have been obtained for the 30014 ← 00001, 30013 ← 00001, 30012 ← 00001, and 00031 ← 00001 bands, and RMS errors <5 × 10 −4 cm −1 for even the weakest fitted bands. This work reduces CO 2 near-infrared line position uncertainties by a factor of 10 or more compared to the 2000 HITRAN line list, which has not been modified since the comprehensive work of Rothman et al. [J. Quant. Spectrosc. Rad. Transfer 48 (1992) 537]. The new line list satisfies the line position accuracies required for the next generation of CO 2 remote sensing instruments, improves the capability of solar-viewing spectrometers to retrieve precise column CO 2 measurements, and provides a secondary frequency standard in the near-infrared.

Stellar Properties of Pre-Main-Sequence Stars from High-Resolution Near-Infrared Spectra

We present high-resolution (R = 50,000) spectra at 2.2 ?m of 16 young stars in the ??Ophiuchi dark cloud. Photospheric features are detected in the spectra of 11 of these sources, all Class II young stellar objects. The five featureless spectra consist of two Class I, two Class I.5, and one Class II. One star, GSS 29, is identified as a spectroscopic binary based on radial velocity variations. The radial velocities for the remaining sample are consistent with 12CO and H2CO gas velocities and further confirm the membership of the sources in the ??Oph cluster. For the 10 spectroscopically single Class II sources, we measure effective temperatures, continuum veiling, and v sin i rotation from the shapes and strengths of atomic photospheric lines by comparison with spectral synthesis models at 2.2 ?m. We measure surface gravities in two stars from the integrated line flux ratio of the 12CO line region at 2.3 ?m and the Na I line region at 2.2 ?m. Although the majority (8/10) of the Class II stars have similar effective temperatures (3530 ? 100 K), they exhibit a large spread in bolometric luminosities (a factor of ~8), as derived from near-IR photometry. In the two stars for which we have surface gravity measurements from spectroscopy, the photometrically derived luminosities are systematically higher than the spectroscopic luminosities. The spread in the photometrically derived luminosities in our other sources suggests either a large spread in stellar ages or nonphotospheric emission in the J band since anomalous and significant veiling at J has been observed in other T Tauri stars. Our spectroscopic luminosities result in older ages on the Hertzsprung-Russell diagram than are suggested by photometry at J or K. Most of our sources show a larger amount of continuum excess (FK ex) than stellar flux at 2.2 ?m (FK*), substantially higher in many cases (rK ? FK ex/FK* = 0.3?4.5). The derived veiling values at K (rK) appear correlated with mid-IR disk luminosity and with Brackett ? equivalent width, corrected for veiling. The derived v sin i rotation is substantial (12?39 km s-1), but systematically less than the rotation measured in Class I.5 (flat) and Class I sources from other studies in Ophiuchus. In four stars (Class I and I.5 sources), the absence of any photospheric lines is likely due to large continuum excess and/or rapid rotation if the stars have late-type photospheres.

High resolution study of near-infrared emission spectra of 142NdO

High resolution near-infrared emission spectra of 142NdO have been recorded using a Fourier transform spectrometer. Molecules were produced by heating 142Nd2O3 to about 2100 K in a special furnace in presence of argon gas. Some 44 bands appear in the region between 7500 and 12600 cm−1, 19 of which classified into 11 systems involving 11 Ω states have been analyzed in rotation. Three of these systems were known from previous studies at moderate resolution which settled the symmetry Ω=4 of the ground state [L.A. Kaledin, E.A. Shenyavskaya, I. Kovacs, Acta Phys. Hung. 54 (1983) 189]. From the present analysis, information is obtained for the ground state in the levels v=0,1,2, and for the low-lying (1)5, (1)3, and (2)4 states in the levels v=0,v=0,1, and v=0, respectively; the (1)5 and (1)3 states show measurable Λ-doubling. The seven upper states either are perturbed or present anomalous Λ-doubling in the levels investigated; for three of them the perturbations could be reduced using a simple 2×2 interaction model. Their Ω symmetry could be ascribed (two states with Ω=3, four states with Ω=4, and one state with Ω=5).

Shock emission in the bipolar post-AGB star IRAS 16594-4656

In this paper we study the near-infrared emission spectrum of IRAS 16594-4656, a bipolar post-AGB star with spectral type B7 and no observed ionization. Using optical and near-infrared photometry we determined the total extinction towards this object to be $A_V=7.5\pm0.4$ mag and derived a distance of $2.2\pm0.4$ kpc, assuming a luminosity of $10^4~L_\odot$. The near-infrared spectrum shows strong H 2 emission lines and some typical metastable shock excited lines such as [Fe ii] 1.257 & 1.644 μ m. We determined the rotational and vibrational excitation temperatures, as well as the ortho-to-para ratio of the molecular hydrogen. Based on these we argue that the H 2 emission is mainly collisionally excited. Line ratios indicate that the H 2 emission originates in a ~25 km s -1 C -type shock. On the other hand, the metastable lines, and especially the [Fe ii] emission lines, indicate the presence of a ~75 km s -1 J -type shock. Hence we postulate that the H 2 emission originates where the stellar wind (with an observed terminal velocity of ~126 km s -1 ) is funneled through an equatorial density enhancement, impinging almost tangentially upon the circumstellar material. The [Fe ii] emission either occurs along the walls of the bipolar lobes where the transverse shock velocity would be higher, or could originate much closer to the central star in shocks in the post-AGB wind itself, or possibly even an accretion disk. Further high resolution near-infrared spectra are currently being obtained to confirm the proposed geometry and kinematics.

Probing hydrogen bond potential surfaces for out-of-plane geometries: Near-infrared combination band torsional (ν6) spectroscopy in (HCl)2

High-resolution near-infrared (IR) spectra of jet cooled (HCl)2 are obtained in the 3000–3070 cm−1 combination band region corresponding to simultaneous excitation of intermolecular out-of-plane torsion (ν6) with intramolecular HCl stretching (ν1,ν2) degrees of freedom. Two (H35Cl)2 bands (plus the isotopically mixed H35Cl–H37Cl bands) due to ν6 torsional excitation are observed. High-resolution spectral analysis of ground-state combination differences and nuclear spin intensity alternation effects permits unambiguous identification of J labeling and tunneling level symmetry, yielding precise rotational constants and vibrational band origins. Comparison with previous far-IR studies suggests assignment of the 3036.52(5) and 3014.86 cm−1 bands to “bound HCl stretch+torsion” (ν2+ν6) combination excitation out of the lower (Γvt=A−←A+) and upper (Γvt=B−←B+) tunneling levels, respectively. A third much weaker band (3035.37 cm−1) is also observed in close proximity with the ν2+ν6 (Γvt=A−←A+) origin, which most likely acquires oscillator strength by state-mixing between the “dark” perturbing state and the ν2+ν6 upper level. These data provide the first opportunity for comparison with exact quantum calculations by Qui and Bačić and co-workers on high level ab initio/semiempirical (HCl)2 potential surfaces, which should facilitate further refinement of intermolecular potentials for out-of-plane twisting of the hydrogen bond.

The First Stellar Abundance Measurements in the Galactic Center: The M Supergiant IRS 7

The first measurement of the photospheric abundances in a star at the Galactic center are presented. A detailed abundance analysis of the Galactic center M2 supergiant IRS 7 was carried out using high-resolution near-infrared echelle spectra. The Fe abundance for IRS 7 was found to be close to solar, [Fe/H] = -0.02 ± 0.13, and nearly identical to the Fe abundance we obtained for the nearby M supergiants α Ori and VV Cep. Analysis of the first and second overtone lines of CO was used to derive an effective temperature of 3600 ± 230 K, a microturbulent velocity of 3.0 ± 0.3 km s-1, and a carbon abundance log e (C) = 7.78 ± 0.13, or [C/H] = -0.77. In addition, we find a high depletion of 0.74 ± 0.32 dex in O and an enhancement of 0.92 ± 0.18 dex in N. These abundances are consistent with the dredge-up of CNO cycle products but require deep mixing in excess of that predicted by standard models for red supergiants. In light of our measured solar Fe abundance for IRS 7, we discuss other indicators of metallicity at the Galactic center, the interpretation of low-resolution near-infrared spectra of late-type giants and supergiants, including the need for caution in using such spectra as measures of metallicity, and the evolution of massive young stars at the Galactic center. We suggest the possibility that rapid stellar rotation is common for stars formed under conditions in the Galactic center, and that extra internal mixing induced by high rotation rates, rather than evolution at high metallicity, is the explanation for many of the unusual properties of the hot emission-line stars in the Galactic center.

Helium absorption and emission towards 1 Ori C

The He I absorption and emission systems towards Theta(1) Ori C, the exciting star of the Orion Nebula, are investigated. To this end, high-resolution near-infrared long-slit spectra centred on the He I 1.083-mu m and Br gamma Lines and an ultra-high-resolution (R similar to 10(6)) spectrum of the optical HeI 3889-Angstrom line have been obtained. These data are supplemented by blue high spectral resolution echelle observations of Theta(1) Ori C and the other members of the Trapezium. Even at R similar to 10(6), the He I absorption profile, associated with foreground gas at a heliocentric velocity of +3 km s(-1), is very smooth, suggesting a simple broadening mechanism and homogeneity. The combination of the He I 2(3)S column density, deduced from the 3889-Angstrom line, with the nondetection of Br gamma emission at the same velocities sets an upper limit on the electron density in this medium of 10(10) m(-3). The He I 1.083-mu m long-slit spectrum shows the familiar background nebular emission, while a second blueshifted component is visible off-star at the same velocities as the absorption on-star. Several mechanisms to explain this emission are explored. We conclude that it is most probably emission formed behind, and leaking through, the absorbing gas layer. A clue to the origin of this emission is found in its spatial distribution: unlike the bright background nebular emission, the blueshifted component peaks symmetrically around the position of Theta(1) Ori C, suggesting a physical association with the star A possible model for the blueshifted emission is that it arises in a large-scale, dense shock front, provoked in some way by the wind of Theta(1) Ori C.

Sequential solvation of HCl in argon: High resolution infrared spectroscopy of ArnHCl (n=1,2,3)

High-resolution near-infrared spectra of the vHCl=1←0 fundamental stretch in Ar2HCl and Ar3HCl have been characterized using a slit-jet infrared spectrometer. Analysis of the jet-cooled, rotationally resolved spectra (i) permits unambiguous identification of the cluster size, (ii) provides vibrationally averaged geometries in the vHCl=1 excited state, and (iii) allows the vibrational shift of the HCl chromophore to be measured as a function of the number of Ar atoms in the complex. The equilibrium structures of ArnHCl (n=1–3) clusters calculated using accurate Ar–Ar and Ar–HCl pair potentials are consistent with the vibrationally averaged structures inferred spectroscopically. The vibrational red-shifts for ArnHCl (n=1–3) reflect a near-linear dependence on the number of Ar atoms, which is qualitatively reproduced by simple classical calculations on vHCl=0 and 1 pairwise additive potential surfaces. Theoretical predictions of the ArnHCl red-shifts in a fcc lattice indicate good agreement with experimental matrix results. However, to achieve this asymptotic limit requires up to n≈54 Ar atoms; this underscores a clear sensitivity to non-nearest neighbor Ar–HCl interactions significantly outside the first solvation shell. Finally, for smaller ArnHCl clusters with only one solvation shell (n=12), the potentials predict an energetic preference for HCl in surface vs interior sites. Analysis indicates that this effect is predominantly due to Ar/HCl size mismatch, which destabilizes the nearest neighbor Ar shell for HCl solvated in the center of the cluster.

High-resolution near-infrared spectra of NGC 4151: Line and continuum analysis

view Abstract Citations (24) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High-Resolution Near-Infrared Spectra of NGC 4151: Line and Continuum Analysis Thompson, Rodger I. Abstract This paper presents new high-resolution near-infrared spectra of the Seyfert 1.5 galaxy NGC 4151. These spectra are the first high-resolution infrared spectra of this galaxy that span the region from 0.87 to 2.5 microns. Analysis of the extensive [Fe II] emission yields electron temperatures and densities consistent with 10^4^ K and 10^4^ cm^-3^ for the Fe II emission-line regions. The high ratio of [Fe II] emission to hydrogen indicates that the majority of Fe is in gaseous form. Analysis of the H_2_ emission indicates that the emission is probably shock excited and that the H_2_ lines have narrower emission-line widths than the observed [S III] narrow-line emission. NGC 4151 appears to have been in a state of high continuum and broad line flux during the observation period; therefore, the equivalent width of some of the narrow line components is lower than in previous observations. Publication: The Astrophysical Journal Pub Date: June 1995 DOI: 10.1086/175732 Bibcode: 1995ApJ...445..700T Keywords: Active Galactic Nuclei; Data Reduction; Galactic Structure; High Resolution; Infrared Spectra; Near Infrared Radiation; Seyfert Galaxies; Electron Density (Concentration); Electron Energy; Emission Spectra; Forbidden Bands; Hydrogen; Iron; Astrophysics; GALAXIES: ACTIVE; GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4151; GALAXIES: ISM; GALAXIES: SEYFERT; INFRARED: GALAXIES full text sources ADS | data products SIMBAD (2) NED (1)

High-resolution near-infrared spectroscopy of water dimer

High-resolution near-infrared spectra are reported for all of the O–H stretch vibrational bands of the water dimer. The four O–H vibrations are characterized as essentially independent proton-donor or proton-acceptor motions. In addition to the rotational and vibrational information contained in these spectra, details are obtained concerning the internal tunneling dynamics in both the ground and excited vibrational states. These results show that for tunneling motions which involve the interchange of the proton donor and acceptor molecules, the associated frequencies decrease substantially due to vibrational excitation. The predissociation lifetimes for the various states of the dimer are determined from linewidth measurements. These results clearly show that the predissociation dynamics is strongly dependent on the tunneling states, as well as the Ka quantum number, indicating that the internal tunneling dynamics plays an important role in determining the dissociation rate in this complex.

High spectral resolution infrared observations of V1057 Cygni

view Abstract Citations (62) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High Spectral Resolution Infrared Observations of V1057 Cygni Hartmann, L. ; Kenyon, S. J. Abstract The authors report high-resolution near-infrared spectra which confirm a key prediction of their accretion disk model for V1057 Cygni. In this model, the outbursts of V1057 Cyg and other FU Ori objects are caused by rapid accretion from a circumstellar disk nebula onto a pre-main-sequence star. Infrared spectra obtained with the KPNO 4 m FTS show that V1057 Cygni does rotate more slowly at 2.3 μm than at 6000 Å, by an amount quantitatively consistent with the simple disk models. The absence of any radial velocity variations in either the infrared or optical spectral regions make it very unlikely that the accretion disk is fed by a companion star but support the view that the accreted material arises from a remnant disk of protostellar material. Publication: The Astrophysical Journal Pub Date: November 1987 DOI: 10.1086/165737 Bibcode: 1987ApJ...322..393H Keywords: Accretion Disks; Infrared Astronomy; Pre-Main Sequence Stars; Stellar Models; Stellar Spectra; Near Infrared Radiation; Radial Velocity; Stellar Evolution; Stellar Mass Accretion; Stellar Mass Ejection; Astrophysics; STARS: ACCRETION; STARS: INDIVIDUAL CONSTELLATION NAME: V1057 CYGNI; STARS: MASS LOSS; STARS: PRE--MAIN-SEQUENCE full text sources ADS | data products SIMBAD (4)

High-resolution near-infrared spectra of normal and super-metal-rich K giants

High-resolution near-infrared spectra of normal and super-metal-rich K giants

Iron abundances in G and K giants from near-infrared spectra

High-resolution near-infrared spectra of ..mu.. Leonis, ..cap alpha.. Arietis, epsilon Virginis, and delta Tauri, published equivalent widths for ..cap alpha.. Bootis and the Sun, and a grid of flux-constant model atmospheres were used to derive iron-to-hydrogen ratios. The results for the super-metal-rich prototype ..mu.. Leo ((Fe/H) = 0.48) are in better agreement with the photometric determinations of iron abundances than with previous spectroscopic analyses. Systematic errors associated with line blending should be less serious than at the shorter wavelengths used for the previous spectroscopic work. 3 figures, 3 tables.

High-Resolution Fourier Spectra of Stars and Planets

view Abstract Citations (28) References (8) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High-Resolution Fourier Spectra of Stars and Planets Connes, Pierre ; Michel, Guy Abstract High-resolution near-infrared spectra (1-2.5 ) have been recorded with a fast-stepping large-maximum-pathdifference interferometer coupled to the Palomar 500-cm telescope. Samples of stellar and planetary spectra are given. Subject headings: spectra, infrared Publication: The Astrophysical Journal Pub Date: May 1974 DOI: 10.1086/181496 Bibcode: 1974ApJ...190L..29C full text sources ADS | data products SIMBAD (16)