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

Jaschek, Mercedes

Malaroda, S.

English

Malaroda, Stella Maris

Servicio de Difusión de la Creación Intelectual

fotometría multicolor de Johnson, Mitchell, Iriarte y Wiesnievsky.En base a esos colores se obtuvieron las correcciones por blanketing para las estrellas metálicas y se graficaron los vectores de blanketing en un diagrama (U-V)/(B-V). Se advierte que los vectores de blanketing son aproxima­damente paralelos con pendiente 3, pero sus módulos son distintos. Este hecho indujo a buscar una posible correlación entre la longitud del vector de blanketing (1) y la metalicidad de la estrella (met) definida como la diferencia en décimos de tipo espectral entre el espectro atribuido según las líneas de los metales menos el es­pectro de hidrógeno.Dicha correlación e’^iste y puede decirse cjue apro­ximadamente se cumple que:1 (en 0™01) = 4 X met.Rotational velocities of B Stars.S. M. MaLARODA * AND H.Levato *Observatorio Astronómico, La PlataAbstract: The rotational velocities of 87 B stars were obtained. The method used is based on the half widths of the Hel 4471 and Mgll 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.Studies of bright A-type stars. Second partJaschek, M., Jaschek, C., Cowley, A. and Cowley, C.Observatorio Astronómico, La Plata y Michigan, EE. UU.Abstract: As a continuation of a paper presented at the 14th meeting of the Association, the colors, spectral types, rotational velocities and photometric narrow-band indices of the A-type stars from paper I, are discussed. An analysis of the data permits to obtain the dispersion of each of these parameters. The im­portance of these dispersions for the treament of interstellar absorption and blanketing corrections is stressed.The paper in full will be published elsewhere.Note on the spectrum of 73 Dra.Jaschek, M. and Malaroda, S. *Observatorio Astronómico, La PlataAbstract: In the peculiar A-type star 73 Draconis the heavy elements Osmium (Z = 76), Platinum (78), Gold (79) and Uranium (92) were identified. Furthennore a large number of nmlecular 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 elswhere.Survey of helium weak stars.Jaschek, C., Jaschek, M. and Arnal, M. *Observatorio Astronómico, La PlataAbstract: The spectra of a dozen stars were obtained in which the colors are bluer than expected according to their spectral types. Eight of them are helium weak. With these objects the percen­tage of stars of this type is increased by 50 %.The paper in full will be publi.shed elsewhere.Heavy elements in peculiar stars.Mercedes Jaschek and Estela BrandiObservatorio Astronómico, La PlataAbstract: In a group of seven late-type peculiar stars a search was made for the heavy elements Os (76), Pt (78), Au (79) and U (92) previously identified in 73 Dra by Jaschek and Malaroda. The results are given in Table I.TABLE I.Disp. Os I Os II Pt II Au I U IIHD gr pec. A/mm (76) (76) (78) (79) (92)15144 Sr 4.5 3977.23 — — — 3859.5856495 Sr 9 — — — — —191742 Sr 9 — — — — —115708 Sr-Eu 9 — the— strongest — —2453 Sr-Cr-Eu 4.5 yes yes yes yes yes25354 Sr-Cr-Eu 9 yes — yes yes 3859 .58-4241,67B CrB Sr-Cr-Eu 2.8 yes — yes 4811.67 yes73 Dra Cr-Sr-Eu 4.5 yes yes yes yes yesUniversidad Nacional de La Plata. * Becaria de la Universidad de La Plata.26

Note on the spectrum of 73 Dra

SEDICI - Repositorio de la UNLP

fotometría multicolor de Johnson, Mitchell, Iriarte y 
Wiesnievsky.
En base a esos colores se obtuvieron las correcciones 
por blanketing para las estrellas metálicas y se graficaron 
los vectores de blanketing en un diagrama (U-V)/(B-V). 
Se advierte que los vectores de blanketing son aproxima­
damente paralelos con pendiente 3, pero sus módulos 
son distintos. Este hecho indujo a buscar una posible 
correlación entre la longitud del vector de blanketing (1) 
y la metalicidad de la estrella (met) definida como la 
diferencia en décimos de tipo espectral entre el espectro 
atribuido según las líneas de los metales menos el es­
pectro de hidrógeno.
Dicha correlación e’^iste y puede decirse cjue apro­
ximadamente se cumple que:
1 (en 0™01) = 4 X met.
Rotational velocities of B Stars.
S. M. MaLARODA * AND H.Levato *
Observatorio Astronómico, La Plata
Abstract: The rotational velocities of 87 B stars were obtained. 
The method used is based on the half widths of the Hel 4471 
and Mgll 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.
Studies of bright A-type stars. Second part
Jaschek, M., Jaschek, C., Cowley, A. and Cowley, C.
Observatorio Astronómico, La Plata y Michigan, EE. UU.
Abstract: As a continuation of a paper presented at the 14th 
meeting of the Association, the colors, spectral types, rotational 
velocities and photometric narrow-band indices of the A-type 
stars from paper I, are discussed. An analysis of the data permits 
to obtain the dispersion of each of these parameters. The im­
portance of these dispersions for the treament of interstellar 
absorption and blanketing corrections is stressed.
The paper in full will be published elsewhere.
Note on the spectrum of 73 Dra.
Jaschek, M. and Malaroda, S. *
Observatorio Astronómico, La Plata
Abstract: In the peculiar A-type star 73 Draconis the heavy 
elements Osmium (Z = 76), Platinum (78), Gold (79) and 
Uranium (92) were identified. Furthennore a large number of 
nmlecular 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 elswhere.
Survey of helium weak stars.
Jaschek, C., Jaschek, M. and Arnal, M. *
Observatorio Astronómico, La Plata
Abstract: The spectra of a dozen stars were obtained in which the 
colors are bluer than expected according to their spectral types. 
Eight of them are helium weak. With these objects the percen­
tage of stars of this type is increased by 50 %.
The paper in full will be publi.shed elsewhere.
Heavy elements in peculiar stars.
Mercedes Jaschek and Estela Brandi
Observatorio Astronómico, La Plata
Abstract: In a group of seven late-type peculiar stars a search 
was made for the heavy elements Os (76), Pt (78), Au (79) 
and U (92) previously identified in 73 Dra by Jaschek and 
Malaroda. The results are given in Table I.
TABLE I.
Disp. Os I Os II Pt II Au I U II
HD gr pec. A/mm (76) (76) (78) (79) (92)
15144 Sr 4.5 3977.23 — — — 3859.58
56495 Sr 9 — — — — —
191742 Sr 9 — — — — —
115708 Sr-Eu 9 — the
— strongest — —
2453 Sr-Cr-Eu 4.5 yes yes yes yes yes
25354 Sr-Cr-Eu 9 yes — yes yes 3859 .58-4241,67
B CrB Sr-Cr-Eu 2.8 yes — yes 4811.67 yes
73 Dra Cr-Sr-Eu 4.5 yes yes yes yes yes
Universidad Nacional de La Plata. * Becaria de la Universidad de La Plata.
26


http://sedici.unlp.edu.ar/bitstream/handle/10915/97671/Resumen__1_p._.pdf?sequence=1

Note on the spectrum of 73 Dra

Abstract

Similar works

Full text

Available Versions

Servicio de Difusión de la Creación Intelectual

SEDICI - Repositorio de la UNLP