TY  - JOUR
U1  - Wissenschaftlicher Artikel
A1  - Huke, Philipp
A1  - Perdelwitz, Volker
T1  - A systematic approach to determining the properties of an iodine absorption cell for high-precision radial velocity measurements
JF  - Monthly Notice of the Royal Astronomy Society
N2  - Absorption cells filled with diatomic iodine are frequently employed as wavelength reference
for high-precision stellar radial velocity determination due to their long-term stability and
low cost. Despite their wide-spread usage in the community, there is little documentation on
how to determine the ideal operating temperature of an individual cell. We have developed a
new approach to measuring the effective molecular temperature inside a gas absorption cell
and searching for effects detrimental to a high-precision wavelength reference, utilizing the
Boltzmann distribution of relative line depths within absorption bands of single vibrational
transitions. With a high-resolution Fourier transform spectrometer, we took a series of 632
spectra at temperatures between 23 and 66◦C. These spectra provide a sufficient basis to test the
algorithm and demonstrate the stability and repeatability of the temperature determination via
molecular lines on a single iodine absorption cell. The achievable radial velocity precision σ RV
is found to be independent of the cell temperature and a detailed analysis shows a wavelength
dependence, which originates in the resolving power of the spectrometer in use and the signal-
to-noise ratio. Two effects were found to cause apparent absolute shifts in radial velocity, a
temperature-induced shift of the order of ∼1 m s−1 K−1 and a more significant effect resulting
in abrupt jumps of ≥50 m s−1 is determined to be caused by the temperature crossing the dew
point of the molecular iodine
KW  - spectrographs
KW  - molecular
KW  - radial velocities.
KW  - iodine
Y1  - 2018
U6  - https://doi.org/10.1093/mnras/sty1523
DO  - https://doi.org/10.1093/mnras/sty1523
VL  - Vol. 479
IS  - 1
SP  - 768
EP  - 775
ER  -