Inici     Començant     Sobreviure a l'Univers    
Inhabited Sky
    News@Sky     Astro Fotografia     La Col·lecció     Fòrum     Blog New!     FAQ     Premsa     Login  

HD 193668


Contingut

Imatges

Carregar la teva Imatge

DSS Images   Other Images


Articles Relacionats

One New and One Suspected Delta Scuti Star: HD 192871 and HD 230990
Not Available

Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOS
We publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html

Nonvariability among lambda Bootis stars
With asteroseismic techniques it is possible to investigate the interiorand the evolutionary status of stars via their frequency spectrum. Bothinformation would be very much needed for lambda Bootis stars, a groupof metal-poor Population I, A-type stars, since no conclusive theoryexists explaining the observed abundance anomalies. Geneva and Stromgrenphotometry place these stars inside the classical instability strip orat least very close to it. We therefore have started an extensivephotometric survey for pulsation in lambda Bootis stars and havediscovered so far 13 new variables. In this paper we present results forstars which presumably are constant, because we are able to establishonly an upper level for possible variability. A typical noise level of 3mmag for Stromgren b was achieved in the relevant frequency domain up to100 d^{-1}. Considering the given noise level of our survey, we concludethat at least 50% of all investigated lambda Bootis stars inside theinstability strip are pulsating, making this group remarkable comparedto stars with similar spectral types. This may suggest that a low(surface) metallicity has an influence on the pulsation Based onobservations obtained at ESO-La Silla, CTIO, SAAO, McDonald Observatory,Instituto Astrofisica Andalucia Observatory.

Nonvariability among lambda Bootis Stars III.: CTIO (1995) and McDonald (1995) Data
Not Available

Enviar un nou article


Enllaços Relacionats

  • - No s'ha trobat enllaços -
Enviar un nou enllaç


Membre dels grups següents:


Dades d'Observació i Astrometria

Constel·lació:Vulpecula
Ascensió Recta:20h20m42.11s
Declinació:+22°16'36.4"
Magnitud Aparent:7.058
Distancia:333.333 parsecs
Moviment propi RA:0
Moviment propi Dec:-5.3
B-T magnitude:6.979
V-T magnitude:7.052

Catàlegs i designacions:
Noms Propis   (Edit)
HD 1989HD 193668
TYCHO-2 2000TYC 1643-39-1
USNO-A2.0USNO-A2 1050-17331692
HIPHIP 100313

→ Sol·licitar més catàlegs i designacions de VizieR