scholarly journals Luminosity Classification of Be Stars by Balmer Line Narrow Band Photometry

1982 ◽  
Vol 98 ◽  
pp. 37-40
Author(s):  
Wolfgang Zeuge

The absolute luminosity of most Be stars can be determined by using Balmer line narrow band photometry with an accuracy of about 0.4 mag. The few cases in which this method fails can be detected.

2020 ◽  
Vol 6 (3) ◽  
pp. 70-73
Author(s):  
Nazila Esmaeili ◽  
Alfredo Illanes ◽  
Axel Boese ◽  
Nikolaos Davaris ◽  
Christoph Arens ◽  
...  

AbstractLongitudinal and perpendicular changes in the blood vessels of the vocal fold have been related to the advancement from benign to malignant laryngeal cancer stages. The combination of Contact Endoscopy (CE) and Narrow Band Imaging (NBI) provides intraoperative realtime visualization of vascular pattern in Larynx. The evaluation of these vascular patterns in CE+NBI images is a subjective process leading to differentiation difficulty and subjectivity between benign and malignant lesions. The main objective of this work is to compare multi-observer classification versus automatic classification of laryngeal lesions. Six clinicians visually classified CE+NBI images into benign and malignant lesions. For the automatic classification of CE+NBI images, we used an algorithm based on characterizing the level of the vessel’s disorder. The results of the manual classification showed that there is no objective interpretation, leading to difficulties to visually distinguish between benign and malignant lesions. The results of the automatic classification of CE+NBI images on the other hand showed the capability of the algorithm to solve these issues. Based on the observed results we believe that, the automatic approach could be a valuable tool to assist clinicians to classifying laryngeal lesions.


2020 ◽  
Vol 6 (9) ◽  
pp. 45-52
Author(s):  
E Krylova

Erodium tataricum is a herbaceous perennial multi-headed tap-root (caudex) plant. Hemicryptophyte. Endemic. The ontogenetic structure was studied in the shrub-herb-grass petrophytic steppe. Individuals of the species have four periods and ten ontogenetic states. It was revealed that the population is normal with an incomplete spectrum. In accordance with the classification of A. A. Uranova and O. V. Smirnova the population is definitive. According to the criterion of the absolute maximum, the population is young. The ontogenetic spectrum of the population is left-sided. A specific ontogenetic spectrum corresponds to a characteristic ontogenetic spectrum, i.e. biology of the species. According to the ontogenetic spectrum, the development of the population is characterized as sustainable. The peculiarity of Erodium tataricum is that on all aerial parts of the plant there is abundant pubescence, but in the old generative ontogenetic state, pubescence on the leaves decreases. Reproduction of the species is carried out by seed. In the subsenile ontogenetic state, senile particulation is possible.


1976 ◽  
pp. 229-231
Author(s):  
David A. Allen
Keyword(s):  

2011 ◽  
Vol 23 ◽  
pp. 106-111 ◽  
Author(s):  
YOSHIKI WADA ◽  
SHIN-EI KUDO ◽  
MASASHI MISAWA ◽  
NOBUNAO IKEHARA ◽  
SHIGEHARU HAMATANI

1994 ◽  
Vol 162 ◽  
pp. 299-300
Author(s):  
John R. Percy

Be stars are hot stars which have shown emission in at least one Balmer line on at least one occasion. As the definition implies, the Be phenomenon can be variable with time: on time scales of days to decades as the circumstellar disc develops and disperses; on time scales of days to months in a few Be stars which are interacting binaries; on time scales of 0.2 to 2 days due to non-radial pulsation or possibly rotation. The Be stars are worthy of photometric study because they are bright and numerous; the nature of the short-term variability is not yet agreed upon; the cause of the development of the disc - and its relationship to the short-term variability - is also not yet known.


1976 ◽  
Vol 72 ◽  
pp. 87-90
Author(s):  
P. M. Williams

The influence of metal abundance and gravity on the relation between spectral type and effective temperatures of late G and K type stars is investigated and calibrated using metal abundances from narrow-band photometry, near infrared photometry and independent luminosity estimates.


Sign in / Sign up

Export Citation Format

Share Document