scholarly journals Method to estimate the effective temperatures of late-type giants using line-depth ratios in the wavelength range 0.97–1.32 μm

2017 ◽  
Vol 473 (4) ◽  
pp. 4993-5001 ◽  
Author(s):  
Daisuke Taniguchi ◽  
Noriyuki Matsunaga ◽  
Naoto Kobayashi ◽  
Kei Fukue ◽  
Satoshi Hamano ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Late Type ◽  
Effective Temperatures ◽  
Line Depth

Galactic Infrared Astronomy

1971 ◽  
Vol 2 (1) ◽  
pp. 14-20 ◽  
Author(s):  
A. R. Hyland
Keyword(s):  
Interstellar Extinction ◽  
Infrared Astronomy ◽  
The Sun ◽  
Late Type ◽  
Infrared Observations ◽  
Effective Temperatures

Until the last six years few infrared observations of astronomical objects (other than the Sun and planets) had been attempted. Those few were primarily concerned with obtaining bolometric corrections and effective temperatures, the variation of bolometric magnitudes of late-type variables, and the derivation of the laws of interstellar extinction.

scholarly journals Spectral Anomalies in the Hyades and Pleiades and in Field Stars with Active Chromospheres

1985 ◽  
Vol 111 ◽  
pp. 415-416
Author(s):  
James A. Rose
Keyword(s):  
Wavelength Range ◽  
Classification System ◽  
Three Dimensional ◽  
Spectral Classification ◽  
Atmospheric Parameters ◽  
Late Type ◽  
Image Tube ◽  
Photographic Image ◽  
Normal Field ◽  
Diagnostic Indices

Widened photographic image-tube spectra at 50 Å mm−1 dispersion have been obtained for a large number of late-type field dwarfs and giants with well-determined atmospheric parameters and for 35 Hyades dwarfs and 31 Pleiades dwarfs. The spectra have a resolution of 2.5 Å and cover the wavelength range λλ3400–4500 Å. A new quantitative three-dimensional spectral classification system is derived for late-type stars and is calibrated using the sample of field dwarfs and giants with known atmospheric parameters. Diagnostic indices are defined by comparing the counts in the bottoms of two neighboring absorption lines or by comparing the counts in two neighboring pseudocontinuum peaks.It is found that the Hyades and Pleiades dwarfs and field dwarfs with strong Ca II H and K emission reversals exhibit well-defined anomalies in their diagnostic indices when compared with normal field dwarfs. These results are summarized in Rose (1984). In LaBonte and Rose (1984), it is shown, from spectra of solar magnetic plages, that all spectral and photometric peculiarities of the Hyades discovered to date, including the original “Hyades anomaly” (Crawford 1969; Strömgren et al. 1982), are manifestations of plage activity.

scholarly journals Stellar Winds and Coronae in Cool Stars

1980 ◽  
Vol 51 ◽  
pp. 279-291 ◽  
Author(s):  
A.K. Dupree ◽  
L. Hartmann
Keyword(s):  
Theoretical Models ◽  
Stellar Winds ◽  
Late Type ◽  
Dwarf Stars ◽  
Giant Stars ◽  
Cool Stars ◽  
Thermally Driven ◽  
Effective Temperatures ◽  
Hot Corona ◽  
Theoretical Results

AbstractRecent observational and theoretical results are reviewed that pertain to the presence and characteristics of stellar coronae and winds in late-type stars. It is found that stars - principally dwarfs - exist with “hot” coronae similar to the Sun with thermally driven winds. For stars, at the lowest effective temperatures, and gravities characteristic of supergiant and giant stars, high temperature (~105K) atmospheres are absent (or if present are substantially weaker than in the dwarf stars), and massive winds are present. There also exist “hybrid” examples - luminous stars possessing both a “hot” corona and a supersonic stellar wind. Constraints for theoretical models are discussed.

Effective temperatures of late-type stars - The field giants from K0 to M6

1980 ◽  
Vol 235 ◽  
pp. 126 ◽  
Author(s):  
S. T. Ridgway ◽  
R. R. Joyce ◽  
N. M. White ◽  
R. F. Wing
Keyword(s):  
Late Type ◽  
Effective Temperatures

scholarly journals Far Ultraviolet Observations of Hot DA White Dwarfs

1989 ◽  
Vol 114 ◽  
pp. 139-143 ◽  
Author(s):  
David Finley ◽  
Gibor Basri ◽  
Stuart Bowyer
Keyword(s):  
Wavelength Range ◽  
White Dwarfs ◽  
Time Dependent ◽  
Flux Correction ◽  
V Band ◽  
International Ultraviolet Explorer ◽  
Effective Temperatures ◽  
Far Ultraviolet ◽  
Ultraviolet Observations ◽  
Flux Calibration

AbstractFar ultraviolet (FUV) fluxes have been used for determining the effective temperatures of a number of DA white dwarfs hotter than 20,000 K. The spectra were obtained with the International Ultraviolet Explorer (IUE). The analysis consisted of comparing the observed FUV fluxes with model fluxes scaled to the V-band flux. After suitable corrections were performed for the time-dependent sensitivity degradation of the IUE, it was found that the available flux calibrations for the IUE were insufficiently accurate for precise temperature determinations. Accordingly, we used seven white dwarfs for which accurate, independent temperature determinations have been made from line profile analyses to improve the accuracy of the IUE flux calibration. The correction to the original calibration was as great as 20% in individual 5-Å wavelength bins, while the average over the IUE wavelength range was 5%. We present both our IUE flux correction and the temperatures obtained for the hot white dwarfs.

A discussion on infared astronomy - Near infrared photometry of late-type stars

1969 ◽  
Vol 264 (1150) ◽  
pp. 209-225 ◽  
Keyword(s):  
Spectral Type ◽  
Near Infrared ◽  
Model Atmosphere ◽  
Spectral Irradiance ◽  
Photometric Method ◽  
Infrared Photometry ◽  
Late Type ◽  
Stellar Diameters ◽  
Effective Temperatures ◽  
The Absolute

A multi-band photoelectric photometer for observations in the ultraviolet, blue and visible and the infrared bands W (1.06μm), X (1.13 μm, Y (1.63 μm) and Z (2.21 μm) has been constructed and applied to both stellar and planetary observations. The results of photometry obtained for 61 stars are presented. The observations at λ = 1.63 μm are shown to exhibit an excess flux due to a minimum in the H opacity in accordance with the predictions of model atmosphere studies. Bolometric corrections are derived for stars of late spectral type from integration of the observed absolute spectral irradiance curve. A simple photometric method for the measurement of stellar diameters is proposed based upon the absolute irradiance observed at 2.21 μm and the 2.21 μm flux at the surface of the star calculated from model atmospheres. Angular diameters derived by this technique are consistent with interferometric results; and, when combined with the bolometric corrections, effective temperatures are found.

LINE-DEPTH RATIOS INH-BAND SPECTRA TO DETERMINE EFFECTIVE TEMPERATURES OF G- AND K-TYPE GIANTS AND SUPERGIANTS

2015 ◽  
Vol 812 (1) ◽  
pp. 64 ◽  
Author(s):  
Kei Fukue ◽  
Noriyuki Matsunaga ◽  
Ryo Yamamoto ◽  
Sohei Kondo ◽  
Naoto Kobayashi ◽  
...  
Keyword(s):  
Effective Temperatures ◽  
Band Spectra ◽  
Line Depth

scholarly journals High precision effective temperatures for 181 F–K dwarfs from line-depth ratios

2003 ◽  
Vol 411 (3) ◽  
pp. 559-564 ◽  
Author(s):  
V. V. Kovtyukh ◽  
C. Soubiran ◽  
S. I. Belik ◽  
N. I. Gorlova
Keyword(s):  
High Precision ◽  
Effective Temperatures ◽  
Line Depth

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.

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