Bibcode
Libich, J.; Harmanec, P.; Vondrák, J.; Yang, S.; Hadrava, P.; Aerts, C.; De Cat, P.; Koubský, P.; Škoda, P.; Šlechta, M.; Uytterhoeven, K.; Mathias, P.
Bibliographical reference
Astronomy and Astrophysics, Volume 446, Issue 2, February I 2006, pp.583-589
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2
2006
Journal
Citations
8
Refereed citations
5
Description
A detailed analysis of a large collection of electronic spectra from
three observatories, together with radial velocities published earlier,
were used to derive a new ephemeris and improved orbital elements for
the ɛ Per binary. Observations covering a time interval of about
37 000 days (101.3 years) can be reconciled with a constant orbital
period of 14.06916 ° ± 0.00004°. The high orbital
eccentricity of 0.555 ± 0.009 was also confirmed. New spectral
observations confirm that there is a periodic variation of the systemic
velocity. Together with new evidence from astrometric observations (also
analyzed here), they confirm the existence of a third body in the system
with an orbital period of about 9600 days (26.3 years), rather than 4156
days, as reported earlier. Application of the disentangling technique to
the Hα spectra with good S/N ratios did not allow detection of
spectral lines of either the secondary or tertiary components. For
plausible inclinations between 30° and 90°, the observed mass
function implies a mass of the secondary M_2=0.85-1.77
M&sun;, if a primary mass is adopted of 13.5 ± 2.0
M&sun;. Attempts to detect the third body via interferometric
observations should continue in spite of this first negative result.