scholarly journals Classification by Photoelectric Measurements of Molecular Bands: Current Status and Future Prospects

1979 ◽  
Vol 47 ◽  
pp. 347-373
Author(s):  
Robert F. Wing
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Current Status ◽  
Two Dimensional ◽  
Future Prospects ◽  
Late Type ◽  
Classification Technique ◽  
Cool Stars ◽  
Infrared Spectral ◽  
Photoelectric Measurements

AbstractAs a classification technique, photoelectric narrow-band photometry is especially effective in the case of late-type spectra, in which molecular bands furnish the most sensitive criteria. Measurements of molecular bands with bandpasses of about 50 Å can be made very efficiently, and for normal stars they can be calibrated in terms of temperature and luminosity. In the case of normal late-type giants and supergiants, two-dimensional classifications can be obtained from measurements of TiO and CN; for very cool giants and for dwarfs it is useful siso to measure VO and CaH, respectively. All these molecules have bands in the red and near-infrared spectral regions, where cool stars are relatively bright and where photometric accuracy is highest.

K–Type Supergiants in the Large Magellanic Cloud

2018 ◽  
Vol 14 (S343) ◽  
pp. 544-545
Author(s):  
Robert F. Wing
Keyword(s):  
Spectral Type ◽  
Near Infrared ◽  
Narrow Band ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Photometric System ◽  
Two Dimensional ◽  
Late Type ◽  
Type K ◽  
Lower Luminosity

AbstractTwo-dimensional spectral classifications, on a narrow-band photometric system that measures near-infrared bands of TiO and CN, are being obtained for several hundred previously unclassified “suspected late-type supergiants” in the Large Magellanic Cloud. The objective is to identify supergiants of spectral type K, which are known to be plentiful in the Small Magellanic Cloud but were thought to be rare in the LMC. In the fields examined to date, 35 % of the targets are found to be K-type supergiants, while 25 % are early-M supergiants and 40 % are foreground stars of lower luminosity.

scholarly journals A Near-Infrared Spectral Sequence of Late M, L, and T Dwarfs

2003 ◽  
Vol 211 ◽  
pp. 389-392
Author(s):  
Michael C. Cushing ◽  
John T. Rayner ◽  
William D. Vacca
Keyword(s):  
Spectral Sequence ◽  
Emission Spectrum ◽  
Atomic Absorption ◽  
Near Infrared ◽  
Late Type ◽  
Medium Resolution ◽  
Infrared Spectral ◽  
Absorption Features ◽  
Initial Results

We present the initial results of a medium resolution, 0.8 to 4.2 μm spectroscopic survey of M, L, and T dwarfs. We have identified the most prominent molecular and atomic absorption features found in the spectra of these late-type dwarfs. We have also compared the spectra to a laboratory FeH emission spectrum and identified nearly 100 features common to the FeH spectrum and the dwarf spectra from 0.99 to 1.8 μm.

Urban Road Materials Identification using Narrow Near Infrared Vision System

2017 ◽  
Vol 7 (3) ◽  
pp. 1171
Author(s):  
Heru Purnomo Ipung ◽  
Handayani Tjandrasa
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Narrow Band ◽  
Vision System ◽  
Optical Filter ◽  
Urban Road ◽  
Infrared Spectral ◽  
Road Materials ◽  
Spectral Patterns ◽  
Infrared Vision

<p>An urban road materials vision system using narrow band near infrared imaging indexes were proposed. This proposed imaging indexes were enhancement for previous work on autonomous multispectral road sensing method. Each urban road material has different near infrared spectral patterns which is as the base of its spectral identification. The new proposed imaging indexes, which using similar formula of NDVI, was normalized with narrow band near infrared spectrum range of 720nm to 1000nm of wavelength, were used to identify concretes, aggregates/sands/rocks, clay, natural dry fibers and bitumen/asphalt that make up most of urban road materials. This paper proposes imaging indexes evaluation from experiment results to identify those urban road materials. There were seven narrow band optical filter sets with the center spectrum at 710nm, 730nm, 750nm, 800nm, 870nm, 905nm and 970nm. Normalization band used was 720nm using high pass optical filter. The proposed multi-spectral imaging indexes were able to show the potential to classify the selected urban road materials, another approach may need to clearly distinguish between concrete and aggregates. The comparison to the previous imaging indexes (NDVI, NDGR, NDBR) were presented that used for urban road materials identification.</p>

scholarly journals A Medium‐Resolution Near‐Infrared Spectral Library of Late‐Type Stars. I.

2004 ◽  
Vol 151 (2) ◽  
pp. 387-397 ◽  
Author(s):  
Valentin D. Ivanov ◽  
Marcia J. Rieke ◽  
Charles W. Engelbracht ◽  
Almudena Alonso‐Herrero ◽  
George H. Rieke ◽  
...  
Keyword(s):  
Near Infrared ◽  
Late Type ◽  
Spectral Library ◽  
Medium Resolution ◽  
Infrared Spectral

Ultra-narrow band near infrared tunable two-dimensional perfect absorber for refractive index sensing

2021 ◽  
Author(s):  
xing huang ◽  
Tao Wang ◽  
Ruoqin Yan ◽  
Xiaoyun Jiang ◽  
Xinzhao Yue ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
Narrow Band ◽  
Perfect Absorber ◽  
Two Dimensional ◽  
Refractive Index Sensing

scholarly journals Applications of Narrow-Band Photometry in the Study of Peculiar Red Giants

2000 ◽  
Vol 177 ◽  
pp. 127-140
Author(s):  
Robert F. Wing
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Red Giants ◽  
Late Type ◽  
Energy Distributions ◽  
Synthetic Spectra ◽  
Continuum Energy ◽  
Qualitative Classification ◽  
Effective Temperatures ◽  
Classification Recognition

Narrow-band photometry, carried out with filters or spectrum scanners, is useful for measuring molecular bandstrengths and continuum energy distributions in late-type stars. This review emphasizes observations by the writer on three different multicolor photometric systems in the near infrared (0.75 − 4.0 μm); a summary of available data is given. While applications to date have been primarily qualitative (classification, recognition of peculiarities, relative temperatures), future applications are expected to be quantitative (determinations of effective temperatures, luminosities, and abundances) and based upon comparison with synthetic spectra.

Wavelength-Selective Solar Thermal Absorber With Two-Dimensional Nickel Gratings

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Bong Jae Lee ◽  
Yu-Bin Chen ◽  
Sunwoo Han ◽  
Feng-Cheng Chiu ◽  
Hyun Jin Lee
Keyword(s):  
Solar Radiation ◽  
Near Infrared ◽  
Broad Band ◽  
Sio2 Film ◽  
Solar Thermal ◽  
Local Magnetic Field ◽  
Absorption Enhancement ◽  
Two Dimensional ◽  
Nickel Substrate ◽  
Infrared Spectral

The direct utilization of solar radiation has been considered a promising energy source because of its abundance, sustainability, and cleanness. The conversion of solar radiation into usable heat largely depends on the absorption characteristics of a solar thermal collector. In the present study, we conducted design analysis of a wavelength-selective absorber composed of a two-dimensional Nickel grating, a thin SiO2 film, and a Nickel substrate. Dimensions of the two-dimensional grating were determined with the Taguchi method, which optimized the spectral absorptance for both polarizations. The spectral absorptance demonstrated a broad-band plateau within the visible and the near-infrared spectral region, but it was significantly suppressed at longer wavelengths. Moreover, the absorptance plateau was nearly insensitive to the incident orientation of solar radiation. Physical mechanisms of the absorption enhancement were elucidated with the local magnetic field distribution.

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