2008/06/25 by P. P. Petrov, G. H. Herbig · 31 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Emission spectrum #Excitation #Line (geometry) #Polar #Radial velocity #Spectral line #Spectrograph #Star (game theory) #Stellar, planetary, and galactic studies #Telescope #astro-ph
paper · pdf · doi:10.1088/0004-6256/136/2/676
published in The Astronomical Journal 136(2), 676-683 (Institute of Physics) · 14 pages, 11 figures, accepted by AJ
arxiv created 2008/06/25 · openalex publication_date 2008/07/08 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
New high-resolution spectra of FU Ori, obtained with the High Resolution Echelle Spectrometer spectrograph at the Keck I telescope in 2003–2006, make it possible to compare the optical line profiles with those predicted by the self-luminous accretion disk model. A dependence of line width on excitation potential and wavelength, expected for a Keplerian disk, is definitely not present in the optical region, nor is the line duplicity due to velocity splitting. The absorption lines observed in the optical region of FU Ori must originate in or near the central object, and here their profiles are shown to be those expected of a rigidly rotating object. They can be fitted by a rapidly rotating ( v sin i = 70 km s −1 ) high-luminosity G-type star having a large dark polar spot, with axis inclined toward the line of sight. Over these years, the radial velocity of FU Ori has remained constant to within ±0.3 km s −1 , so there is no indication that the star is a spectroscopic binary. These results apply to the optical region (λ < 8800 Å); more distant, cooler regions of the disk contribute in the infrared.