The spectrum of SI II in peculiar a-type stars

En los espectros de seis estrellas peculiares del tipo A, se identificó una veintena de líneas, hasta el momento sin identificar, con líneas provenientes de niveles de alta excitación del Si II. Entre otras, la línea λ 4200 también corresponde al Si II, en blend con Fe III. El trabajo "in extenso" será publicado en las "Publications of the Astronómica! Society of the Pacific".In the spectra of six peculiar A-type stars, twenty lines for which no identification was available, were identified with lines corresponding to high excitation levels of Si II. Among others also λ 4200 corresponds to Si II, blended with Fe' III. The paper will be published in full in the "Publications of the Astronomical Society of the Pacific". 17Asociación Argentina de Astronomí

Spectral classification of stars with spectral peculiarities

Como resultado de una búsqueda sistemática de estrellas peculiares australes entre los tipos espectrales B8 y F5 y entre magnitudes aparentes 5.5 y 7.0 se listan las clasificaciones en el sistema MK de 23 estrellas con lineas metálicas, 5 peculiares y 7 objetos con espectros compuestos.As the result of a systematic search for southern stars having spectral peculiarities, in the spectral range B8 to F5 and between apparent magnitudes 5.5 and 7.0, the classification in the MK system are given for 23 metallic line stars, 5 peculiar A-type stars and 7 objects with composite spectra.Asociación Argentina de Astronomí

The helium rich star HD 96446

Se relata la detección de una nueva estrella rica en helio. Se hacen algunas consideraciones sobre los elementos presente en ellas 7 sobre la magnitud absoluta del objeto. El trabajo será publicado in extenso en las Publications of the Astronomical Society of the Pacific. Discusión: SAHADE comenta que no tiene mucho sentido hablar de tipo espectral siendo una estrella tan peculiar.A new helium-rich star has been found. A short description of the spectrum ia given, together with some considerations aoout the lumlnosity of the object. A more detailed paper on this subject will appear ln the Publ. A.S.P.Asociación Argentina de Astronomí

Peculiar stars in the Southern Hemisphere

Results from a program of spectral classification of the A-type stars south of -30°, and with magnitudes between 5“0 and 7m0, which according to the Henry Draper Catalogue show some spectral peculiarity, are presented. Twenty-six new peculiar A type stars are listed and classifed. The paper will be published In full elsewhere.Asociación Argentina de Astronomí

La precisión alcanzable en clasificación espectral

The attainable precision in spectral classification in the MK system is studied making use of the recent "Catalogue of stars classified in the MK system" by Jaschek, Conde and Sierra. It is concluded that the internal dispersion of the different series is comparable and that it is of the order of half of a tenth in spectral class and half a luminosity class. The paper in full will be published in the proceedings of I.A.U. Symposium N " 24.Asociación Argentina de Astronomí

Star formation in open clusters

En base a la fórmula dada por Kushwaha y Kothari para la fragmentación al azar de una masa de gas, se analizaron los diagramas de frecuencia de masas de ocho asociaciones y cúmulos. Se encontró que la fórmula antecitada satisface los diagramas observacionales en todos los casos.The authors have analyzed the mass frequency diagrams of eight associations and open clusters in order to see if they can be represented by Kushwaha and Kbthari's formula of the random fragmentation of a gas cloud. It can be shown that the formula fits all diagrams.Asociación Argentina de Astronomí

Some remarks on metallic-line stars

It Is shown that the photoelectric (B-V) colors of the metallic line stars are correlated with the spectral types derived from the hydrogen lines. Consequently these stars can be grouped into several physically similar groups. The discrepancies different absolute magnitude determinations made in the past appear therefore as consequences of selection effects. A discussion of. the luminosities suggests further that the metallieity is a luminosity effect. Prom the number of Balmer lines that can be seen on the speotra, it is concluded that the electron pressure in metallic line stars must be the same as in main sequence stars. The paper will be published in full elsewhere.Asociación Argentina de Astronomí

The helium rich star HD 96446

Se relata la detección de una nueva estrella rica en helio. Se hacen algunas consideraciones sobre los elementos presente en ellas 7 sobre la magnitud absoluta del objeto. El trabajo será publicado in extenso en las Publications of the Astronomical Society of the Pacific. Discusión: SAHADE comenta que no tiene mucho sentido hablar de tipo espectral siendo una estrella tan peculiar.A new helium-rich star has been found. A short description of the spectrum ia given, together with some considerations aoout the lumlnosity of the object. A more detailed paper on this subject will appear ln the Publ. A.S.P.Asociación Argentina de Astronomí

Spectroscopic notes: I. HD 133738 and HD 6882

During the past years a number of spectra of southern objects have been taken by the authors and their collaborators at the Bosque Alegre station of the Córdoba Observatory.Asociación Argentina de Astronomí

La precisión alcanzable en clasificación espectral

The attainable precision in spectral classification in the MK system is studied making use of the recent "Catalogue of stars classified in the MK system" by Jaschek, Conde and Sierra. It is concluded that the internal dispersion of the different series is comparable and that it is of the order of half of a tenth in spectral class and half a luminosity class. The paper in full will be published in the proceedings of I.A.U. Symposium N " 24.Asociación Argentina de Astronomí