Rotational velocities of B stars

The rotational velocities of 87 B stars were obtained. The method used is based on the half widths of the HeI 4471 and MgII 4481 lines calibrated on a series of standard stars. Finally the present results were compared with Buscombe’s and Slettebak’s with the following results: V sin i ( Bu ) = 1.42 V sin i (SI) ± 46 km/sec. V sin i ( Bu ) = 1.56 V sin i (Ma-Le) ± 55 km/sec. The complete paper will be published elsewhere.Asociación Argentina de Astronomí

Note on the spectrum of 73 Dra

In the peculiar A-type star 73 Draconis the heavy elements Osmium (Z = 76), Platinum (78) , Gold (79) and Uranium (92) were identified. Furthermore a large number of molecular bands due to CN and to a lesser degree to CH, were detected. This star is the first one up to now in which both anomalies were detected. The complete paper will be published elsewhere.Asociación Argentina de Astronomí

Rotational velocities of B stars

The rotational velocities of 87 B stars were obtained. The method used is based on the half widths of the HeI 4471 and MgII 4481 lines calibrated on a series of standard stars. Finally the present results were compared with Buscombe’s and Slettebak’s with the following results: V sin i ( Bu ) = 1.42 V sin i (SI) ± 46 km/sec. V sin i ( Bu ) = 1.56 V sin i (Ma-Le) ± 55 km/sec. The complete paper will be published elsewhere.Asociación Argentina de Astronomí

Rotational velocities of B stars

The rotational velocities of 87 B stars were obtained. The method used is based on the half widths of the HeI 4471 and MgII 4481 lines calibrated on a series of standard stars. Finally the present results were compared with Buscombe’s and Slettebak’s with the following results: V sin i ( Bu ) = 1.42 V sin i (SI) ± 46 km/sec. V sin i ( Bu ) = 1.56 V sin i (Ma-Le) ± 55 km/sec. The complete paper will be published elsewhere.Asociación Argentina de Astronomí

Note on the spectrum of 73 Dra

In the peculiar A-type star 73 Draconis the heavy elements Osmium (Z = 76), Platinum (78) , Gold (79) and Uranium (92) were identified. Furthermore a large number of molecular bands due to CN and to a lesser degree to CH, were detected. This star is the first one up to now in which both anomalies were detected. The complete paper will be published elsewhere.Asociación Argentina de Astronomí

Identificación de elementos en HR 1100

Continuando con el estudio de estrellas peculiares en base a espectros de alta dispersión (16.9 Å/mm), calibrados, obtenidos en Kitt Peak, se detallan los elementos identificados en la estrella débil de He HR 1100.Asociación Argentina de Astronomí

La variable de Helio HD 184927

Se obtuvieron en el Observatorio de Kitt Peak durante 1976, 20 espectrogramas Coudé (16.9 Å/mm) con las correspondientes calibraciones. Se midieron anchos equivalentes y velocidades radiales confirmándose el período de 9.48 días encontrado por Bond y Levato con estimaciones visuales. Se observan variaciones en los anchos equivalentes del H, He, CII, MgII, NII y probablemente SiII, SiIII y OII. La velocidad radial del H es constante en el presente nivel de detección mientras que las del He son variables. Se trabaja actualmente en un modelo que explique las observaciones.Asociación Argentina de Astronomí

El programa espectroscópico sobre cúmulos abiertos y asociaciones en el Observatorio de La Plata

El programa iniciado en enero de 1977 es fundamentalmente una continuación del realizado desde Kitt Peak durante 1975 y 1976. El objeto es estudiar distintos tipos de correlaciones entre estos objetos y para ello es necesario proveer tipos espectrales buenos, detectar peculiares y proveer velocidades de rotación axial. Estos son los datos observacionales que el programa provee. La lista de objetos incluidos en el mismo consta de 40 cúmulos y 10 asociaciones aproximadamente, de los cuales se han observado hasta el momento, total o parcialmente, NGC 2287, NGC 6231, Berg Harris Nº 99, Praesepe, Trumpler 14, Trumpler 16, Collinder 228 y NGC 6611.Asociación Argentina de Astronomí

The helium peculiar star HD 22920

Continuing with the spectroscopic analysis of peculiar stars. HD 22920 (22 Eri) was studied. All the elements present in its atmosphere were identified. 22 Eri is not an extreme CP stars and, when compared with other peculiar stars of the same group and with stellar effective temperature, it shares their anomalies and can be included among the helium-weak and the Silicon stars.Asociación Argentina de Astronomí