22. The Metallic-Line Stars

63 Tau. - The K line has an intensity about equal to a star of class A1. The general metallic-line spectrum resembles closely the star Leo (F0 III). 63 Tau is in the Taurus cluster and has an absolute magnitude of +2.8. As Leo is certainly much more luminous, the absolute-magnitude effect observed for 63 Tau is a false one. There seems to be no explanation of the spectrum on the basis of two normal stars.

a Gem (ft). - The spectral type from the K line is about A1; from the metallic lines it is about A5. All lines appear to originate in one star, since a Gem (ft) is a spectroscopic binary with only one spectrum visible.

UMa (ft). - The spectral type from the K line is about A2 and from the metallic lines is around A7. UMa (ft) is a member of the Ursa Major cluster and has an absolute magnitude of about +2.0.

Ser. - The spectral type from the K line is near A2 and from the metallic lines about A7.

a² Lib. - The spectral type from the K line is about A3 and from the metallic lines near A7. The absolute magnitude is probably in the neighborhood of +1.5.

Lyr A. - The spectral type from the K line is about A3 and from the metallic lines around A7. Lyr B appears to be an ordinary main-sequence star of type F0. The intensities of the lines are closely similar to Cep.

15 UMa.- The spectral type from the K line is around A3 the metallic lines appear to be fairly similar in intensity to Pup (F6 II). The absolute-magnitude effect observed is probably false, as 15 UMa has a proper motion of 0".132.

UMa. - The K line has an intensity similar to a normal A3 star. The metallic-line spectrum matches closely that of Pup (F6 II). The high absolute magnitude indicated from the metallic lines is probably illusory; UMa has a proper motion of 0".122.

Plate 23. The ``Metallic-Line Star'' 63 Tauri

High resolution image