The two components of χ Aquilae can be separated in the spectrum and their relative brightness has been measured, but their other properties are uncertain. The cool component is a G2 bright giant or supergiant and is visually brighter than the hot component, so it is treated as the primary. The hot component is a late B- or A-type star, presumed to be a main-sequence star.[5][3]
The observed spectrum of the primary star is G2 Ib, a yellow supergiant. It is calculated to have an absolute magnitude of −2.1. The secondary is observed to have a spectral type of B5.5 and is expected to be a main-sequence star with an absolute magnitude of −1. However, the brightness difference between a G2 supergiant and a B5.5 dwarf is expected to be larger. It is unclear whether the primary is not a supergiant or the secondary is brighter than a main-sequence star.[5]
As of 2004, the secondary is located at an angular separation of 0.418 arcseconds along a position angle of 76.7° from the primary.[8] The separation and position angle are both decreasing.[9]
^Scardia, M.; et al. (April 2006), "Speckle observations with PISCO in Merate - II. Astrometric measurements of visual binaries in 2004", Monthly Notices of the Royal Astronomical Society, 367 (3): 1170–1180, Bibcode:2006MNRAS.367.1170S, doi:10.1111/j.1365-2966.2006.10035.x.