scholarly journals The luminosity classification of late-type stars using microphotometer tracings.

1955 ◽  
Vol 60 ◽  
pp. 174
Author(s):  
J. B. Oke
Keyword(s):  
Late Type

scholarly journals An atlas of cool supergiants from the Magellanic Clouds and typical interlopers

2018 ◽  
Vol 618 ◽  
pp. A137 ◽  
Author(s):  
Ricardo Dorda ◽  
Ignacio Negueruela ◽  
Carlos González-Fernández ◽  
Amparo Marco
Keyword(s):  
Photographic Plate ◽  
Magellanic Clouds ◽  
Spectral Classification ◽  
Late Type ◽  
Spectral Ranges ◽  
Work Done

We present an atlas composed of more than 1500 spectra of late-type stars (spectral types from G to M) observed simultaneously in the optical and calcium triplet spectral ranges. These spectra were obtained as part of a survey to search for cool supergiants in the Magellanic Clouds and were taken over four epochs. We provide the spectral and luminosity classification for each spectrum (71% are supergiants, 13% are giants or luminous giants, 4% are carbon or S stars, and the remaining 12% are foreground stars of lesser luminosities). We also provide a detailed guide for the spectral classification of luminous late-type stars, the result of the extensive classification work done for the atlas. Although this guide is based on classical criteria, we have put them together and re-elaborated them for modern CCD-spectra as these criteria were scattered among many different works and mainly conceived for use with photographic plate spectra. The result is a systematic, well-tested process for identifying and classifying luminous late-type stars, illustrated with CCD spectra of standard stars and the classifications of our own catalogue.

scholarly journals A Test of the Accuracy of low Dispersion Objective Prism: Spectral Classification of Late-Type Stars Using DDO Photometry

1976 ◽  
Vol 72 ◽  
pp. 73-73
Author(s):  
J. J. Clariá ◽  
W. Osborn
Keyword(s):  
Band System ◽  
Class I ◽  
Spectral Features ◽  
Spectral Classification ◽  
Late Type ◽  
Intermediate Band ◽  
Metal Abundance ◽  
Objective Prism ◽  
Low Dispersion

A test has been made of the reliability of the multidimensional classification of late-type stars from low dispersion objective prism plates recently attempted by Stock and Wroblewski. Such classification at low dispersion is difficult due to the problem of separating the effects of luminosity from those of abnormal metal abundance. A sample of the stars classified by Stock and Wroblewski as metal weak (pec) and of those classified as luminous stars (class I) were observed using the DDO intermediate-band system. The photometry shows that the stars classified as pec are indeed population II giants, of low metal abundance ([Fe/H] < −1.0). The stars classified as I, however, were found in general not to be true supergiants but rather a mixture of various types of giants, such as CN strong stars, with spectral features that resemble, in one way or another, those of higher luminosity stars.

scholarly journals The peculiar symbiotic object V1329 Cygni: single-star versus binary models

1982 ◽  
Vol 70 ◽  
pp. 165-168
Author(s):  
Jiri Grygar ◽  
Drahomir Chochol
Keyword(s):  
Emission Line ◽  
Near Infrared ◽  
Emission Lines ◽  
Symbiotic Stars ◽  
Late Type ◽  
Single Star ◽  
Star Versus

The variable emission-line object V1329 Cyg (= HBV 475) was discover red by Kohoutek (1969).Crampton and Grygar (1969) identified more than 100 emission lines in the blue portion of the spectrum, while Andrillat (1969) found evidence for the late-type (M) spectrum in the near infrared. This justified the classification of the object among the symbiotic stars. The classification was subsequently confirmed by all authors who studied the spectroscopic evolution of the object.

scholarly journals Virgo and other Late-Type Dwarfs

1998 ◽  
Vol 11 (1) ◽  
pp. 105-106
Author(s):  
N. Brosch ◽  
A. Heller ◽  
E. Almoznino
Keyword(s):  
Star Formation ◽  
Virgo Cluster ◽  
Disk Galaxies ◽  
Late Type ◽  
Morphological Classification ◽  
External Effects ◽  
Low Mass ◽  
Galaxy Collisions ◽  
Intracluster Matter

We attempt to solve the question of star formation triggers and star formation laws by studying samples of simple objects and defining carefully the possible external effects. Among the star formation (SF) triggers there are some that can operate only in large disk galaxies. These are shear instabilities and density waves, and we can eliminate them if we restrict the sample to diskless objects of low mass. Such galaxies, which do show star formation, are late-type dwarf galaxies (DGs). Other SF triggers are related to the neighborhood a galaxy finds itself in. Such triggers are galaxy-galaxy collisions and galaxy-intracluster matter interactions (stripping, shocks, etc.). These also can be eliminated by properly choosing the sample to study; one selects galaxies from neigh-borhoods of widely different densities (of galaxies) and compares their SF parameters. We selected our first samples in a region of relatively high galaxy density, where a complete morphological classification of objects was available, and suitable depth in brightness sampling could readily be achieved. This is the Virgo cluster, where Binggeli, Sandage and Tammann (1985, BST) provide a sample of more than 2000 DGs. Among those, some 25% are of late type and are classified by BST as blue compact dwarfs (BCDs), as Magellanic irregulars (Im) of five possible sub-classes, or as combinations of those two classifications.

On the absolute magnitudes of late-type giant stars

1966 ◽  
Vol 24 ◽  
pp. 317-321
Author(s):  
B. Ljunggren ◽  
T. Oja
Keyword(s):  
Late Type ◽  
Group V ◽  
Group Iii ◽  
Giant Stars ◽  
The Absolute ◽  
Type Giant ◽  
Photometric Measurements ◽  
Absolute Magnitudes ◽  
Group D

The classification of late-type stars in the Uppsala system is made from photometric measurements of the criteriagandc, gmeasuring the break at the G-band andcthe cyanogen absorption. On the basis of these criteria the stars are divided into luminosity groups. Earlier only two groups, dwarfs and giants, were used. A few years ago a refinement in luminosity classification was introduced (1), the stars being divided into four luminosity groups designated d, dg, g, and c in the order of increasing luminosity. Specially the groups d and g have been defined so as to make them as homogeneous as possible. The group d corresponds to the MK luminosity group V and g approximately to the luminosity group III.

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