# A New Analysis of Stark and Zeeman Effects on Hydrogen Lines in Magnetized DA White Dwarfs

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## Abstract

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## 1. Introduction

## 2. Stark Line Shape Modeling

## 3. Zeeman Effect in Magnetized White Dwarfs

## 4. White Dwarf Spectrum Analysis

## 5. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

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**Figure 1.**Plot of H$\alpha $ calculated at ${N}_{e}={10}^{17}$ cm${}^{-3}$, ${T}_{e}={T}_{i}=1$ eV, with a magnetic field of 200 T. An observation direction perpendicular to the magnetic field has been assumed. The spectrum exhibits a clean Zeeman triplet structure.

**Figure 2.**Some white dwarfs can have a magnetic field strong enough so that the quadratic Zeeman effect becomes significant. The spectrum becomes asymmetric and presents more components. Here, a calculation has been done assuming $B=2000$ T.

**Figure 3.**Plot of the Sloan Digital Sky Survey (SDSS) + J085830 + 412635.12 spectrum in the 4500–7000 Å wavelength range. This spectrum corresponds to a magnetized DA white dwarf. The H$\alpha $ and H$\beta $ lines present a triplet structure, which is characteristic of Zeeman effect.

**Figure 4.**An analysis of the shape of absorption lines provides information on the plasma parameters. Here, an adjustment of (

**a**) H$\alpha $ and (

**b**) H$\beta $ using the Stark-Zeeman line shape model is presented. These lines have been analyzed independently assuming a homogeneous slab geometry. The obtained values for ${N}_{e}$ and B provide a first order-of-magnitude estimate.

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**MDPI and ACS Style**

Kieu, N.; Rosato, J.; Stamm, R.; Kovačević-Dojcinović, J.; Dimitrijević, M.S.; Popović, L.Č.; Simić, Z. A New Analysis of Stark and Zeeman Effects on Hydrogen Lines in Magnetized DA White Dwarfs. *Atoms* **2017**, *5*, 44.
https://doi.org/10.3390/atoms5040044

**AMA Style**

Kieu N, Rosato J, Stamm R, Kovačević-Dojcinović J, Dimitrijević MS, Popović LČ, Simić Z. A New Analysis of Stark and Zeeman Effects on Hydrogen Lines in Magnetized DA White Dwarfs. *Atoms*. 2017; 5(4):44.
https://doi.org/10.3390/atoms5040044

**Chicago/Turabian Style**

Kieu, Ny, Joël Rosato, Roland Stamm, Jelena Kovačević-Dojcinović, Milan S. Dimitrijević, Luka Č. Popović, and Zoran Simić. 2017. "A New Analysis of Stark and Zeeman Effects on Hydrogen Lines in Magnetized DA White Dwarfs" *Atoms* 5, no. 4: 44.
https://doi.org/10.3390/atoms5040044