Cepheids in the solar neighbourhood (artist’s impression)

Artist's impression of the local neighbourhood of the Sun and its setting within our galaxy, the Milky Way (see insert above). The figure shows the positions of some bright stars (in white) in the sky as well as the eight Cepheids used in the investigation (in blue). After the rotation of the Milky Way had been accounted for (red arrow), it seemed that the Cepheids were all ''falling'' towards the Sun (blue arrows; these are not to scale : in reality the blue velocities are typically a factor one hundred smaller than the velocity around the Milky Way). New, very precise measurements with the HARPS instrument have shown that this apparent ''fall'' is due to effects within the Cepheids themselves and is not related to the way the Milky Way rotates. The motion indicated by the blue arrows is thus an illusion. The scale of the image is given in light-years (ly).

Herkunftsnachweis:

ESO

Über das Bild

ID:eso0830a
Typ:Illustration
Veröffentlichungsdatum:19. September 2008
Dazugehörige Veröffentlichungen:eso0830
Größe:2997 x 1992 px

Über das Objekt

Name:Stars
Typ:Milky Way
Milky Way : Star : Type : Variable
Kategorie:Illustrations

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