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The PRL Stabilized High-Resolution Echelle Fiber-fed Spectrograph: Instrument Description and First Radial Velocity Results.
- Source :
- Publications of the Astronomical Society of the Pacific; Feb2014, Vol. 126 Issue 936, p133-147, 15p
- Publication Year :
- 2014
-
Abstract
- We present spectrograph design details and initial radial velocity results from the PRL optical fiberfed high-resolution cross-dispersed echelle spectrograph (PARAS), which has recently been commissioned at the Mount Abu 1.2 m telescope in India. Data obtained as part of the postcommissioning tests with PARAS show velocity precision better than 2 ms<superscript>-1</superscript> over a period of several months on bright RV standard stars. For observations of σ Dra, we report 1:7 ms<superscript>-1</superscript> precision for a period of 7 months, and for HD 9407, we report 2:1 ms<superscript>-1</superscript> over a period of 2 months. PARAS is capable of single-shot spectral coverage of 3800-9500 Å at a resolution of ~67; 000. The RV results were obtained between 3800 and 6900 Å using simultaneous wavelength calibration with a thorium-argon (ThAr) hollow cathode lamp. The spectrograph is maintained under stable conditions of temperature with a precision of 0.01-0.02° C (rms) at 25.55° C and is enclosed in a vacuum vessel at pressure of 0:1 ± 0:03 mbar. The blaze peak efficiency of the spectrograph between 5000 and 6500 Å, including the detector, is ~30%; it is ~25% with the fiber transmission. The total efficiency, including spectrograph, fiber transmission, focal ratio degradation (FRD), and telescope (with 81% reflectivity) is ~7% in the same wavelength region on a clear night with good seeing conditions. The stable point-spread function (PSF), environmental control, existence of a simultaneous calibration fiber, and availability of observing time make PARAS attractive for a variety of exoplanetary and stellar astrophysics projects. Future plans include testing of octagonal fibers for further scrambling of light and extensive calibration over the entire wavelength range up to 9500 Å using thorium-neon (ThNe) or uranium-neon (UNe) spectral lamps. Thus, we demonstrate how such highly stabilized instruments, even on small aperture telescopes, can contribute significantly to the ongoing radial velocity searches for low-mass planets around bright stars. [ABSTRACT FROM AUTHOR]
- Subjects :
- SPECTROGRAPHS
ECHELLE gratings
RADIAL velocity of stars
THORIUM
ASTROPHYSICS
Subjects
Details
- Language :
- English
- ISSN :
- 00046280
- Volume :
- 126
- Issue :
- 936
- Database :
- Complementary Index
- Journal :
- Publications of the Astronomical Society of the Pacific
- Publication Type :
- Academic Journal
- Accession number :
- 94776079
- Full Text :
- https://doi.org/10.1086/675352