The eShel Spectrograph: A Radial-velocity Tool at the Wise Observatory

• Published in: Publications of the Astronomical Society of the Pacific Vol. 129; no. 976; pp. 65002 - 65010
• Main Authors: Engel, M., Shahaf, S., Mazeh, T.
• Format: Journal Article
• Language: English
• Published: Philadelphia The Astronomical Society of the Pacific 01-06-2017; IOP Publishing
• Subjects: binaries: spectroscopic; instrumentation: spectrographs; Observatories; Systematics; techniques: radial velocities; Velocity
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1088/1538-3873/aa65c6

The eShel, an off-the-shelf, fiber-fed echelle spectrograph ( R 10,000 ), was installed on the 1 m telescope at the Wise observatory in Israel. We report the installation of the multi-order spectrograph, and describe our pipeline to extract stellar radial velocity from the obtained spectra. We also introduce a new algorithm-UNICOR, to remove radial-velocity systematics that can appear in some of the observed orders. We show that the system performance is close to the photon-noise limit for exposures with more than 107 counts, with a precision that can get better than 200 m s−1 for F-K stars, for which the eShel spectral response is optimal. This makes the eShel at Wise a useful tool for studying spectroscopic binaries brighter than mV = 11. We demonstrate this capability with orbital solutions of two binaries from projects being performed at Wise.