Spectrum of the Star Ll. 13412

Abstract

THE spectrum of the star Ll. 13412 appears to be in some respects unique. It consists mainly of three bright lines having wave-lengths of 545, 486, and 466 millionths of a millimetre. Four other stars have hitherto been found whose spectra are of this character. Three of them are in Cygnus, and have lines whose wave-lengths are 580, 568, 536, and 467. The fourth star, Oeltzen 17681, has lines at about 582 and 470 (NATURE, vol. xxii. p. 483). The line or band at 467 appears to be common to all, and that at 580 to the last four. The line at 486 in Ll. 13412 coincides with the F line of hydrogen, but is not visible in the other stars. The line at 545 is also absent in them. This star therefore appears to resemble the others in kind, but not in the material of which it is composed. It is also much brighter than the others, so that it is not a difficult object with a small telescope. Its position for 1880 is in R.A. 6h. 49.3m. and Dec. –23° 47′. It is easily found as a seventh magnitude star about 15′ north of 0prime; Canis Majoris.