Red spectra taken at Mount Wilson and at Lick confirm Widing's conclusion that 17 Leporis is a binary system and that the secondary component is a late type star. Widing's tentative period has been improved to 258.2 days, and values of K₂= 22.5 km/sec and f(M₂) =0.30 Mₒ have been derived. The primary star's velocity curve will have to be derived from the Mg II λ 4481 line but the presently available material in the photographic region is not sufficient for the purpose. Struve's earliest Yerkes radial velocities from Mg II λ 4481 seem to confirm the period but nothing is suggested in regard to the value of K₁.Asociación Argentina de Astronomí

Ringuelet, Adela Emilia

Sahade, Jorge

Wallerstein, G

English

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32One W-R star, HD 5Ö896, was observed in the cluster Cr 121. This star with = -2 , according to the color-magnitude diagram of the cluster (Feinstein, unpublished), is in the main sequence very near the turn-off point where the stars begin to evolve to the red giants- The cluster is very young arxl its diagran is the same as that of h and x  Persei.In N G C  6321 there are two W-R stars. This cluster observed by Kron and Breckinridge in the PV system, and by Feinstein in the UBV system (unpublished), shows that these two stars are also at the turn-off point. The absolute magnitude of both are around = -4 .5 . Two of stars are present above both W-R objects.The fact that some W-R are members of clusters, is also confirmed by Westerlund who found this kind of stars in three clusters of LMC. A ll are on the main sequence and very near the point where the evolution to the giants. The absolute magnitude is around -6.Andrillat showed that the field W-R stars have absolute magnitudes in a range between M = -1.5 and -5 , so that these stars display a large spread in absolute magnitude.As this fact is confirmed in clusters, and they are also always near the turn- off point, it seems that the condition of W- R stage is connected in some way with the begining of the evolution to the red giants. Then, any main sequence star may be a W-R- in the range of absolute magnitude between -1 and - 6.LA ESTRELLA PECULIAR 17 LEPORISA. Ringuelet-Kaswalder*, J . Sahade* y G . Wallerstein (Observatorio Astronómico, La Plata y Berkeley Astronomical Department, University of California)Espectrogramas tornados en Mount Wilson y en L ick , en la región del rojo, confirman la conclusión de Widing de que 17 Leporis es un sistema binario y que la estrella secundaria es de tipo tardTo. El perfodo tentativo de Widing ha podido ser corregido a 258,2 dfas y se ha obtenido K2 = 22 ,5  km/seg y f ( 71X2) ~ O>3O0.La curva de velocidades de la estrella prima­ria debe ser obtenida de la Imea de Mg II en X 4481, pero el material de que se dispone en la actualidad en la región fotográfica no es suficiente para tal fin . Las velocidades de Mg II X 4481 obtenidas hace años por Staive en el Observatorio de Yerices parecen confirmar elviene del trabajo anteriorReferencesAndrillat, Y . ,  Etoiles a raies d'émission p.61 1957 Breckinridge J. B. and Kron G . E ., Pub. A. S.P, 75. 248 1963.Westerlund B ., Kungl. Svenska V . Handl., 8 N 3 , 1961.33perrodo pero no permiten obtener conclusiones respecto al valor de K .^Red spectra taken at Mount Wilson and at Lick confirm Widing's conclusion that 17 Lepo- ris is a binary system and that the secondary component is a late type star. Widing's tentative period has been improved to 258.2 days, and values of K2 = 22.5 km/sec and f =0.30 0 have been derived. The primary star's velocity curve w ill have to be derived from the Mg II X 4481 line but the presently avaiibble material in the photographic region is not sufficient for the purpose. Struve's earliest Yerkes radial velocities from Mg II X4481 seem to confirm the period but nothing is suggested in regard to the value of K ].TECN ICA FO TO G RAFICA  PARA LA PRUEBA DE LA CAUSTICAJorge E. Simmons(Observatorio Astronómico, La Plata)Basado en propiedades de la prueba de la cáustica v isual, el autor ha desarrollado una técnica fotográfica capaz de documentar en forma objetiva las caracterfsticas de las superfi­cies ópticas cóncavas que pueden ser estudiadas con la cáustica visual.Las placas obtenidas se miden por medio de una máquina capaz de medir en dos coordena­das y se reducen aplicando métodos conocidos. El acuerdo entre el método visual y el foto­gráfico es bueno y mejora a medida que aumenta la relación D /F . Se presentan esquemas de instalación, planillas de medidas y reducciones y gráficos comparativos del método visual y la técnica fotográfica.El trabajo será publicado completo en otra parte.Based on some properties of the visual caustic test, the author has developed a photogra­phic technique capable of rendering an objective document about the features of concave optical surfaces which are measurable with the visual caustic test.The plates are measured in a machine capable of measuring in two coordinates and are reduced following well known methods. The agreement between the visual and photographic methods is good and improves at high D/F ratios. Drawings of the apparatus are presented along with measurement and reduction sheets and graphs comparing the visual method and photographic technique;.The complete paper w ill be published elsewhere.viene del trabajo anterior* Miembros de la Carrera del Investigador C ientffico , Consejo Nacional de Investigaciones CientTficas y Técnicas de la República Argentina.

La estrella peculiar 17 Leporis

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32
One W-R star, HD 5Ö896, was observed in the cluster Cr 121. This star with = -2 , 
according to the color-magnitude diagram of the cluster (Feinstein, unpublished), is in the 
main sequence very near the turn-off point where the stars begin to evolve to the red giants- 
The cluster is very young arxl its diagran is the same as that of h and x  Persei.
In N G C  6321 there are two W-R stars. This cluster observed by Kron and Breckinridge in 
the PV system, and by Feinstein in the UBV system (unpublished), shows that these two stars 
are also at the turn-off point. The absolute magnitude of both are around = -4 .5 . Two of 
stars are present above both W-R objects.
The fact that some W-R are members of clusters, is also confirmed by Westerlund who 
found this kind of stars in three clusters of LMC. A ll are on the main sequence and very near 
the point where the evolution to the giants. The absolute magnitude is around -6.
Andrillat showed that the field W-R stars have absolute magnitudes in a range between 
M = -1.5 and -5 , so that these stars display a large spread in absolute magnitude.
As this fact is confirmed in clusters, and they are also always near the turn- off point, it 
seems that the condition of W- R stage is connected in some way with the begining of the 
evolution to the red giants. Then, any main sequence star may be a W-R- in the range of 
absolute magnitude between -1 and - 6.
LA ESTRELLA PECULIAR 17 LEPORIS
A. Ringuelet-Kaswalder*, J . Sahade* y G . Wallerstein 
(Observatorio Astronómico, La Plata y Berkeley 
Astronomical Department, University of California)
Espectrogramas tornados en Mount Wilson y en L ick , en la región del rojo, confirman la 
conclusión de Widing de que 17 Leporis es un sistema binario y que la estrella secundaria es 
de tipo tardTo. El perfodo tentativo de Widing ha podido ser corregido a 258,2 dfas y se ha 
obtenido K2 = 22 ,5  km/seg y f ( 71X2) ~ O>3O0.La curva de velocidades de la estrella prima­
ria debe ser obtenida de la Imea de Mg II en X 4481, pero el material de que se dispone en 
la actualidad en la región fotográfica no es suficiente para tal fin . Las velocidades de Mg II 
X 4481 obtenidas hace años por Staive en el Observatorio de Yerices parecen confirmar el
viene del trabajo anterior
References
Andrillat, Y . ,  Etoiles a raies d'émission p.61 1957 
Breckinridge J. B. and Kron G . E ., Pub. A. S.P, 75. 248 1963.
Westerlund B ., Kungl. Svenska V . Handl., 8 N 3 , 1961.
33
perrodo pero no permiten obtener conclusiones respecto al valor de K .^
Red spectra taken at Mount Wilson and at Lick confirm Widing's conclusion that 17 Lepo- 
ris is a binary system and that the secondary component is a late type star. Widing's tentative 
period has been improved to 258.2 days, and values of K2 = 22.5 km/sec and f =0.30 0 
have been derived. The primary star's velocity curve w ill have to be derived from the Mg II 
X 4481 line but the presently avaiibble material in the photographic region is not sufficient 
for the purpose. Struve's earliest Yerkes radial velocities from Mg II X4481 seem to confirm 
the period but nothing is suggested in regard to the value of K ].
TECN ICA FO TO G RAFICA  PARA LA PRUEBA DE LA CAUSTICA
Jorge E. Simmons
(Observatorio Astronómico, La Plata)
Basado en propiedades de la prueba de la cáustica v isual, el autor ha desarrollado una 
técnica fotográfica capaz de documentar en forma objetiva las caracterfsticas de las superfi­
cies ópticas cóncavas que pueden ser estudiadas con la cáustica visual.
Las placas obtenidas se miden por medio de una máquina capaz de medir en dos coordena­
das y se reducen aplicando métodos conocidos. El acuerdo entre el método visual y el foto­
gráfico es bueno y mejora a medida que aumenta la relación D /F . Se presentan esquemas de 
instalación, planillas de medidas y reducciones y gráficos comparativos del método visual y 
la técnica fotográfica.
El trabajo será publicado completo en otra parte.
Based on some properties of the visual caustic test, the author has developed a photogra­
phic technique capable of rendering an objective document about the features of concave 
optical surfaces which are measurable with the visual caustic test.
The plates are measured in a machine capable of measuring in two coordinates and are 
reduced following well known methods. The agreement between the visual and photographic 
methods is good and improves at high D/F ratios. Drawings of the apparatus are presented 
along with measurement and reduction sheets and graphs comparing the visual method and 
photographic technique;.
The complete paper w ill be published elsewhere.
viene del trabajo anterior
* Miembros de la Carrera del Investigador C ientffico , Consejo Nacional de Investigaciones 
CientTficas y Técnicas de la República Argentina.


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La estrella peculiar 17 Leporis

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