Contenuti
Immagini
Carica la tua immagine
DSS Images Other Images
Articoli relazionati
Evidence of helium abundance differences between young groups of stars Seven groups of B-type stars - Sco-Cen, NGC 6231, LacOBI,OriOBIb, h + chi Per, CepOBIII, and field stars - wereinvestigated photoelectrically to determine whether helium abundance isuniform in the solar neighborhood and in a region of the spiral arm ofthe Galaxy. Observations were performed using an echelle spectrometer inthe narrow band index of the I (4026) of the He I-4026 line. Amodel-atmosphere analysis of I (4026) and the beta index of the H betaline shows that in the spectral range B O-B 2, the relation between I(4026) and beta is insensitive to differences in the surface gravity butsensitive to differences in the helium to hydrogen ratio. It is foundthat stars in the two groups most distant from the sun - h + chi Per andCepOBIII - have a lower helium abundance than stars in the solarneighborhood.
|
Sottometti un nuovo articolo
Link relazionati
Sottometti un nuovo link
Membro dei seguenti gruppi:
|
Osservazione e dati astrometrici
Costellazione: | Fornace |
Ascensione retta: | 02h45m40.47s |
Declinazione: | -33°52'28.1" |
Magnitudine apparente: | 8.183 |
Distanza: | 87.032 parsec |
Moto proprio RA: | -14.4 |
Moto proprio Dec: | -2.2 |
B-T magnitude: | 8.713 |
V-T magnitude: | 8.227 |
Cataloghi e designazioni:
|