Infrared Spectroscopy of Symbiotic Stars. Vi. Combined Orbits for Two S-Type Systems: V455 Scorpii and Ss 73-90

Abstract

We have combined new infrared radial velocities and previously obtained spectropolarimetric observations to compute orbits of the M6 giants in two southern S-type symbiotic systems. The spectropolarimetric data enable the orbital inclinations of the systems to be determined, placing greater constraints on the properties of the components. V455 Sco has a circular orbit with a period of 1398 ± 6 days and an inclination of 94 • ± 1 • . The orbit of SS 73-90 has a period of 898 ± 5 days, a modest eccentricity of 0.16, and an inclination of 97 • ± 7 • . The center of mass velocity of each system is large, −77.9 km s −1 for V455 Sco and 89.5 km s −1 for SS 73-90, making them members of the old disk population. The M giant component of each system is likely on the asymptotic giant branch. From estimates of the M giants' radii we predict that both systems are eclipsing and provide ephemerides to search for the eclipses. For V455 Sco, the predicted eclipses are found in data from the Harvard College Observatory plate archives. The He ii emission feature near 1.0123 µm is associated with the hot component in both systems. However, the orbits produced from the emission-line radial velocities do not lead to masses that are consistent with other results.

Infrared Spectroscopy of Symbiotic Stars. Viii. Orbits for Three S-Type Systems: Ae Arae, Y Coronae Australis, and Ss 73-147

“…The sum of the squared velocity residuals from the sine curve fit was computed, and the period having the smallest value of that sum was adopted as the best preliminary period. With this period identified, spectroscopic orbital elements of the systems were determined with various computer programs (Fekel et al 2008) for eccentric and circular orbits.…”

“…These various complications conspire to make well-determined orbital elements difficult to obtain. As a result, of the nearly 200 symbiotic systems listed in the recent catalog of Belczyński et al (2000), only about 15% have had spectroscopic orbital elements determined for the cool giant component (Mikołajewska 2003;Fekel et al 2008). In seven previous papers in this series (Fekel et al 2000a(Fekel et al , 2000b(Fekel et al , 2001(Fekel et al , 2007(Fekel et al , 2008Hinkle et al 2006Hinkle et al , 2009 we have determined the orbital elements for the late-type component in 21 systems, seven of which are first orbits.…”

Masses of white dwarfs in symbiotic binaries

“…In a series of eight papers (Fekel et al 2017(Fekel et al , 2015(Fekel et al , 2010(Fekel et al , 2008(Fekel et al , 2007(Fekel et al , 2001(Fekel et al , 2000a we measured the single-lined spectroscopic orbit of the late-type star in 30 symbiotic binary systems. Two parameters from the orbital solution, eccentricity and mass function, can be used to evaluate the group statistically.…”