A sun in the spectroscopic binary IM Pegasi, the guide star for the Gravity Probe B Mission

Marsden, S.C., Berdyugina, S.V., Donati, J-F., Eaton, J.A., Williamson, M.H., Ilyin, I., Fischer, D.A., Muñoz, M., Isaacson, H., Ratner, M.I., Semel, M., Petit, P., and Carter, B.D. (2005) A sun in the spectroscopic binary IM Pegasi, the guide star for the Gravity Probe B Mission. The Astrophysical Journal, 634 (2). L173-L176.

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We present the first detection of the secondary of the spectroscopic binary system IM Pegasi (HR 8703), the guide star for the NASA-Stanford relativity gyroscope mission Gravity Probe B. In support of this mission, high-resolution echelle spectra of IM Peg have been obtained on an almost nightly basis. Applying the technique of least-squares deconvolution, we achieve very high signal-to-noise ratio line profiles and detect the orbit of the secondary of the system. Combining almost 700 new radial velocity measurements of both the primary and secondary of the system with previous measurements, we derive improved orbital parameters of the IM Peg system. Using these estimates along with the previously determined range of orbital inclination angles for the system, we find that the primary of IM Peg is a giant of mass 1.8 ± 0.2 M⊙, while the secondary is a dwarf of mass 1.0 ± 0.1 M⊙.

Item ID: 16708
Item Type: Article (Research - C1)
ISSN: 1538-4357
Keywords: binaries: spectroscopic; stars: individual (IM Pegasi)
Date Deposited: 02 Aug 2011 22:14
FoR Codes: 02 PHYSICAL SCIENCES > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 100%
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