The Visual Orbit of ι Pegasi

Abstract

We have determined the visual orbit for the spectroscopic binary ι Pegasi with interferometric visibility data obtained by the Palomar Testbed Interferometer in 1997. ι Pegasi is a double-lined binary system whose minimum masses and spectral typing suggests the possibility of eclipses. Our orbital and component diameter determinations do not favor the eclipse hypothesis: the limb-to-limb separation of the two components is 0.151 ± 0.069 mas at conjunction. Our conclusion that the ι Peg system does not eclipse is supported by high-precision photometric observations. The physical parameters implied by our visual orbit and the spectroscopic orbit of Fekel and Tomkin (1983) are in good agreement with those inferred by other means.In particular, the orbital parallax of the system is determined to be 86.9 ± 1.0 mas, and masses of the two components are determined to be 1.326 ± 0.016 M ⊙ and 0.819 ± 0.009 M ⊙ respectively.

Resolved double-lined spectroscopic binaries: A neglected source of hypothesis-free parallaxes and stellar masses

“…The SB2 systems presented by Delfosse et al (1999) are absent because neither the radial velocities nor the visual observations have been published yet. For the TPI systems (Malbet et al 1998;Koresko et al 1998;Boden et al 1999), the nature of the visual observations is the reason why we disregarded them. Indeed, for the time being, our code cannot simultaneously fit radial velocities and optical interferometric raw data (i.e.…”

“…Thanks to speckle observation programmes (e.g., McAlister 1997), many spectroscopic binaries have been resolved for twenty years. Furthermore, new interferometers (NPOI , TPI (Colavita et al 1999)) have already shown their capabilities by providing the visual orbit of short period binaries (Malbet et al 1998;Koresko et al 1998;Boden et al 1999).…”

Modeling Circumstellar Disks of B-Type Stars With Observations From the Palomar Testbed Interferometer

“…PTI's limiting night-tonight measurement error is σ V 2 SYS ≈ 1.5%-1.8%, the source of which is most likely a combination of effects: uncharacterized atmospheric seeing (in particular, scintillation), detector noise, and other instrumental effects. This measurement error limit is an empirically established floor from the previous study of Boden et al (1999).…”

Classical Observations of Visual Binary and Multiple Stars

“…If the P 1 day the rotation of the Earth can help fill out the uv-plane (e.g., the SUSI measures of β Cen; Davis et al 2005) and also allows observers to express parameters in ρ-θ space. The difficulty may be in rapid moving systems when only two-element interferometers are used (e.g., the PTI orbits of Boden et al 1999). Are we in a regime where the B-V 2 are only a intermediate step and we'll eventually end up back in a ρ-θ way of thinking, or do we need a new paradigm and new orbit calculation tools?…”