Determination of the Interstellar Extinction Toward WN Stars from Observed ubv Color Indices

1991 ◽  
pp. 640-640
Author(s):  
William D. Vacca ◽  
Werner Schmutz
Keyword(s):  
Interstellar Extinction ◽  
Color Indices

scholarly journals Determination of the Interstellar Extinction Toward WN Stars from Observed UBV Color Indices

1991 ◽  
Vol 143 ◽  
pp. 640-640
Author(s):  
William D. Vacca ◽  
Werner Schmutz
Keyword(s):  
Power Law ◽  
Theoretical Models ◽  
Interstellar Extinction ◽  
High Quality ◽  
Central Wavelength ◽  
Color Indices ◽  
Image Position ◽  
The Continuum

Recent observations of Wolf-Rayet stars by Massey (1984) and Torres-Dodgen and Massey (1988) have yielded high quality, absolutely calibrated spectra of nearly all known Wolf- Rayet objects. These observations also indicate that discontinuities, or “jumps”, are present in the continuum spectra of some Wolf-Rayet stars. Such continuum jumps are predicted by the current theoretical models of Wolf-Rayet atmospheres. In general, these models provide good fits to the observed spectra of Wolf-Rayet stars. The models also indicate that, between jumps, the intrinsic continuum can be closely approximated by a power law in wavelength. In this case, we have the following relation between the intrinsic colors: where and Z3645 is the strength of the He II (η = 4) jump at 3645 Å in mags. This relation holds because the central wavelength of the u filter (λu = 3650 Å) is nearly coincident with that of the He II jump. In addition, models of WN stars with helium-dominated atmospheres predict a correlation between D3645 and (6 - v)o:

Multicolor CCD Photometry of the Open Cluster IC 361

2010 ◽  
Vol 19 (1-2) ◽  
Author(s):  
J. Zdanavičius ◽  
S. Bartašiūtė ◽  
R. P. Boyle ◽  
F. J. Vrba ◽  
K. Zdanavičius
Keyword(s):  
Open Cluster ◽  
Interstellar Extinction ◽  
Ccd Photometry ◽  
Color Indices ◽  
Absolute Magnitudes

AbstractCCD photometry in the eight-color Vilnius + I system for 7250 stars down to I =19.6 mag has been obtained in the 20′ × 26′ field of the open cluster IC 361 in Camelopardalis. The catalog of 1420 stars down to V ~ 18.5 mag is presented. It contains the coordinates, V magnitudes and seven color indices, quantitative photometric spectral types, absolute magnitudes and distances. The interstellar extinction is found to be non-uniform across the field, with the values of A

Evaluation of Pasta Thermal Treatment By Determination of Carbohydrates, Furosine, and Color Indices

2012 ◽  
Vol 6 (10) ◽  
pp. 2721-2731 ◽  
Author(s):  
A. Cavazza ◽  
C. Corradini ◽  
M. Rinaldi ◽  
P. Salvadeo ◽  
C. Borromei ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Color Indices

scholarly journals Absolute Magnitude Determination of Be Stars: The Inadequacy of the 2200 Å Bump

1993 ◽  
Vol 137 ◽  
pp. 787-788 ◽  
Author(s):  
V. Doazan ◽  
A. De La Fuente ◽  
M. Barylak ◽  
N. Cramer
Keyword(s):  
Absolute Magnitude ◽  
Interstellar Extinction ◽  
Be Stars ◽  
Distance Determination ◽  
Type Spectrum ◽  
Magnitude Determination

AbstractWe present fax UV observations of Pleione made with the IUE satellite at two epochs: in 1979, when the star exhibited a strong shell spectrum and, in 1991, when it showed a Be-type spectrum. Between these two epochs, the 2200 Å bump changed dramatically, thus, rendering it inadequate for interstellar extinction/distance determination.

Star Classification Possibilities with the Gaia Spectrophotometers. III. The Classification Accuracy with Decontaminated BP/RP Spectra

2011 ◽  
Vol 20 (2) ◽  
Author(s):  
V. Straižys ◽  
R. Lazauskaitė
Keyword(s):  
Classification Accuracy ◽  
Photometric System ◽  
Acceptable Accuracy ◽  
Color Indices ◽  
Medium Band ◽  
Star Classification

AbstractA medium-band 12-color photometric system, based on the decontaminated Gaia BP/RP spectra, has been proposed in our Paper II. Here we analyze a possibility to apply some versions of this system for the determination of temperatures and gravities of stars both in the absence and the presence of interstellar reddening. The possibility to supplement this system with the broad BP and RP passbands is verified. We conclude that the system gives an acceptable accuracy of temperatures and luminosities if the accuracy of color indices is 0.02 mag or better and if the parallaxes of stars are known.

Investigation of the stellar population and determination of interstellar extinction toward the Chandra Bulge Field based on RTT-150 data

2010 ◽  
Vol 36 (11) ◽  
pp. 788-795 ◽  
Author(s):  
D. I. Karasev ◽  
M. G. Revnivtsev ◽  
A. A. Lutovinov ◽  
R. A. Burenin
Keyword(s):  
Stellar Population ◽  
Interstellar Extinction

scholarly journals Extragalactic Stellar Astronomy with the Brightest Stars in the Universe

2007 ◽  
Vol 3 (S250) ◽  
pp. 313-326
Author(s):  
Rolf Kudritzki ◽  
Miguel A. Urbaneja ◽  
Fabio Bresolin ◽  
Norbert Przybilla
Keyword(s):  
Local Group ◽  
Spectroscopic Method ◽  
Interstellar Extinction ◽  
Stellar Astronomy ◽  
Quantitative Spectral Analysis ◽  
Determination Methods ◽  
Future Work ◽  
The Universe ◽  
Visual Light

AbstractA supergiants are objects in transition from the blue to the red (and vice versa) in the uppermost HRD. They are the intrinsically brightest “normal” stars at visual light with absolute visual magnitudes up to −9. They are ideal to study young stellar populations in galaxies beyond the Local Group to determine chemical composition and evolution, interstellar extinction, reddening laws and distances. We discuss most recent results on the quantitative spectral analysis of such objects in galaxies beyond the Local Group based on medium and low resolution spectra obtained with the ESO VLT and Keck. We describe the analysis method including the determination of metallicity and metallicity gradients. A new method to measure accurate extragalactic distances based on the stellar gravities and effective temperatures is presented, the flux weighted gravity – luminosity relationship (FGLR). The FGLR is a purely spectroscopic method, which overcomes the uncertainties introduced by interstellar extinction and variations of metallicity, which plague all photometric stellar distance determination methods. We discuss the perspectives of future work using the giant ground-based telescopes of the next generation such as the TMT, the GMT and the E-ELT.

scholarly journals Russian/Former Soviet Union Experience in Small Telescope Usage for Investigation of Interstellar Matter (ISM) and Nebulae

2001 ◽  
Vol 183 ◽  
pp. 343-344
Author(s):  
N.G. Bochkarev
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Standard Technique ◽  
Interstellar Extinction ◽  
Interstellar Matter ◽  
Optical Range ◽  
The Galaxy ◽  
Long Time ◽  
Union Experience

The deepest tradition in ISM study in the optical range was built in Russia/FSU by V.Fessenkov, the founder of Fessenkov Astrophysical (Aph) Institute (AFIF, Kazakhstan) and G.Shain (Crimean Aph.Obs. - CrAO, Ukraine). The tradition was handed over to SAI (Moscow) by I. Shklovski and S.Pikelner, to Abastumani Aph. Obs. (AAO, Georgia), where a catalogue of dark nebulae (Khavtassi, 1960) was produced, and to Byurakan Aph. Obs. (BAO, Armenia).For a long time 0.3-0.7 m telescopes were used for determination of interstellar extinction in the Galaxy by the standard technique (SAI; Engelhart Astron. Obs. of Kazan Univ., Russia; AAO; BAO and others. The most sophisticated investigations were carried out in Lithuania (e.g. Straizys, 1977; Sudzius, 1974).

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