New spectroscopy of U gem

• Echevarría, J. ^[1] ; Ramírez, S. H. ^[2] ; Fuentes, M. ^[3] ; Sánchez, L. J. ^[1] ; Patiño, V. ^[5] ; Chavushyan, V. ^[4]
  1. [1] Universidad Nacional Autónoma de México

     Universidad Nacional Autónoma de México

     México

     
  2. [2] University of Warwick

     University of Warwick

     Reino Unido

     
  3. [3] Universidad de Sonora

     Universidad de Sonora

     México

     
  4. [4] Instituto Nacional de Astrofísica, Óptica y Electrónica

     Instituto Nacional de Astrofísica, Óptica y Electrónica

     México

     
  5. [5] 1. Instituto Nacional de Astrofísica, Óptica y Electrónica, Tonantzintla, Puebla, México. 2. Max-Planck-Institut für Radioastronomie, Bonn, Germany

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• Localización: Revista mexicana de astronomía y astrofísica, ISSN-e 0185-1101, Vol. 59, Nº. 2, 2023, págs. 191-200
• Idioma: inglés
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• Resumen

  • We present new optical spectroscopic observations of U Geminorum obtained during a quiescent stage. We perform a radial velocity analysis of three Balmer emission lines yielding inconsistent results. Assuming that the radial velocity semi amplitude accurately reflects the motion of the white dwarf, we arrive at masses for the primary which are in the range of Mwd = 1.21−1.37M☉. Based on the internal radial velocity inconsistencies and results produced from the Doppler tomography - wherein we do not detect emission from the hot spot, but rather an intense asymmetric emission overlaying the disc, reminiscent of spiral arms - we discuss the possibility that the overestimation of the masses may be due to variations of gas opacities and a partial truncation of the disc.