Contributed Talk - Splinter ATNG

Thursday, 14 September 2023, 15:15   (H 2036)

Improving the accuracy of inexpensive out-of-the-shelf optical echelle spectrograghs

L. Stock and A. Schrimpf
Philipps university of Marburg

Hot close binary stars are an interesting field of research, especially after the first exoplanets orbiting such a binary system were found via direct imaging. A high cadence of RV data points is very crucial for good estimates of the binaries properties. Most high resolution spectrographs, e.g. HARPS or FEROS, don't offer such a good cadence in their archives. We present a possibility to make own RV measurements with inexpensive and of-the-shelf optical echelle spectrographs, especially the fiber-fed Shelyak eShel with a resolution of about R = 12 000. These spectrographs can be located at local observatories and are therefore a good opportunity for own, independent measurements. We were able to achieve a single exposure accuracy of about Delta RV = 100 m/s and a limiting magnitude of about 9mag at a 20inch f/10 telescope located in Hessen, Germany, which is not sufficient for detecting exoplanets, but for detecting binaries. This is possible due to a better control over the spectrographs point spread function and temperature shifts during the night.