Determination of Landé factors in the F 4 Δ 5/2,7/2 state of 56 FeH by laser excitation spectroscopy

Crozet, P.; Dobrev, Georgi; Richard, C.; Ross, A.J.

doi:10.1016/j.jms.2014.07.005

Cited by 6 publications

(3 citation statements)

References 18 publications

(41 reference statements)

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“…Assuming the field strength is the same in our measurements, that would induce g eff = 1 ± 0.24. Note that theoretical and laboratory values of g eff , although difficult to obtain for a molecule, are quoted in a range 0.8 to 1.25 by several authors for the transitions in the F 4 ∆ − X 4 ∆ system (Brown et al 2006;Harrison et al 2008;Afram et al 2008;Shulyak et al 2014;Crozet et al 2014), in good agreement with our empirical estimate. We also note that, as we always take the same value of g eff in this study, trends and behaviours intrinsic to the sample remain valid and are independent of the exact value of g eff .…”

Section: Zeeman Broadeningsupporting

confidence: 88%

SPIRou input catalogue: activity, rotation and magnetic field of cool dwarfs

Moutou

Hébrard

Morin

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Based on optical high-resolution spectra obtained with CFHT/ESPaDOnS, we present new measurements of activity and magnetic field proxies of 442 low-mass K5-M7 dwarfs. The objects were analysed as potential targets to search for planetary-mass companions with the new spectropolarimeter and high-precision velocimeter, SPIRou. We have analysed their highresolution spectra in an homogeneous way: circular polarisation, chromospheric features, and Zeeman broadening of the FeH infrared line. The complex relationship between these activity indicators is analysed: while no strong connection is found between the large-scale and small-scale magnetic fields, the latter relates with the non-thermal flux originating in the chromosphere.We then examine the relationship between various activity diagnostics and the optical radial-velocity jitter available in the literature, especially for planet host stars. We use this to derive for all stars an activity merit function (higher for quieter stars) with the goal of identifying the most favorable stars where the radial-velocity jitter is low enough for planet searches. We find that the main contributors to the RV jitter are the large-scale magnetic field and the chromospheric non-thermal emission.In addition, three stars (GJ 1289, GJ 793, and GJ 251) have been followed along their rotation using the spectropolarimetric mode, and we derive their magnetic topology. These very slow rotators are good representatives of future SPIRou targets. They are compared to other stars where the magnetic topology is also known. The poloidal component of the magnetic field is predominent in all three stars.

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Section: Zeeman Broadeningsupporting

confidence: 88%

SPIRou input catalogue: activity, rotation and magnetic field of cool dwarfs

Moutou

Hébrard

Morin

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…These techniques, for example, use the Zeeman effect to tune transitions in and out resonance by changing the applied magnetic field [6]. Zeeman effects can also be probed directly using standard spectroscopic techniques to study molecules in magnetic fields [7,8,9]. In a similar fashion, Zeeman effects are increasingly being used to form, probe and trap molecules at ultra-cold temperatures [10] for example by use of magnetically tunable Feshbach resonances [11].…”

Section: Introductionmentioning

confidence: 99%

“…Landé g-factors of AlO obtained using Duo wavefunctions with Eqs (8,9). and the QN approximation, Hund's cases (a) and (b).…”

mentioning

confidence: 99%

Predicted Landé g-factors for open shell diatomic molecules

Semenov

Yurchenko

Tennyson

2016

Journal of Molecular Spectroscopy

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The program Duo (Yurchenko et al., Computer Phys. Comms., 202 (2016) 262) provides direct solutions of the nuclear motion Schrödinger equation for the (coupled) potential energy curves of open shell diatomic molecules. Wavefunctions from Duo are used to compute Landé g-factors valid for weak magnetic fields; the results are compared with the idealized predictions of both Hund's case (a) and Hund's case (b) coupling schemes. Test calculations are performed for AlO, NO, CrH and C 2 . The computed g J 's both provide a sensitive test of the underlying spectroscopic model used to represent the system and an indication of whether states of the molecule are well-represented by the either of the Hund's cases considered. The computation of Landé g-factors is implemented as a standard option in the latest release of Duo.

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Correlations between laboratory line lists for FeH, CrH, and NiH and M-star spectra collected with ESPaDOnS and SPIRou

Crozet,

Morin,

Ross

et al. 2023

A&A

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Context. Molecular bands of metal oxides and hydrides dominate the optical and near-infrared spectra of M dwarfs. High-resolution spectra of these bands have immense potential for determining many properties of these stars, such as effective temperature, surface gravity, elemental abundances, radial velocity, or surface magnetic fields. Techniques are being developed to do this but remain limited by the current availability and accuracy of molecular data and spectral line lists. Aims. This paper reports metal monohydride line lists selected from near-infrared and visible laboratory data to show that specific bands in several electronic transitions can be used to identify CrH, NiH, and FeH in M stars and to determine radial velocities from Doppler shifts. The possibility of measuring magnetic fields is also investigated for FeH and CrH. Methods. We used systematic cross-correlation analysis between unpolarised spectra from a selection of M stars and state-specific laboratory line lists. These lists were generated from a combination of existing data and new laboratory laser-excitation spectra recorded at Doppler-limited resolution, in zero-field conditions or in magnetic fields up to 0.6 tesla. Results. We show that transitions at visible wavelengths in FeH and NiH, usually neglected in the analysis of the spectra of M-type stars, do in fact contribute to the spectra, and we demonstrate the influence of magnetic sensitivity on selected transitions in CrH and FeH. Conclusions. Although the new line lists focus on transitions recorded at temperatures significantly lower than those of stellar objects, they remain pertinent because they cover some band-head regions of high spectral density. FeH bands can provide a useful supplement to atomic lines for the analysis of high-resolution optical and near-infrared spectra of M dwarfs. We demonstrate the influence of a magnetic field on CrH signatures around 862 nm.

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Determination of Landé factors in the F 4 Δ 5/2,7/2 state of 56 FeH by laser excitation spectroscopy

Cited by 6 publications

References 18 publications

SPIRou input catalogue: activity, rotation and magnetic field of cool dwarfs

SPIRou input catalogue: activity, rotation and magnetic field of cool dwarfs

Predicted Landé g-factors for open shell diatomic molecules

Correlations between laboratory line lists for FeH, CrH, and NiH and M-star spectra collected with ESPaDOnS and SPIRou

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