Phase-resolved optical spectroscopy of the rapidly varying white dwarf ZTF 1851+1714

Fuente: arXiv
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Autori principali: Pedersen, C. C., Knudsen, M. R. M., Valeckas, K., Izzo, L., Tauris, T. M., Fynbo, J. P. U.
Natura: Preprint
Pubblicazione: 2025
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author Pedersen, C. C.
Knudsen, M. R. M.
Valeckas, K.
Izzo, L.
Tauris, T. M.
Fynbo, J. P. U.
author_facet Pedersen, C. C.
Knudsen, M. R. M.
Valeckas, K.
Izzo, L.
Tauris, T. M.
Fynbo, J. P. U.
contents We report on phase-resolved optical spectroscopy and photometry in the R and B bands of the white dwarf candidate ZTF 185139.81+171430.3. The source has been reported to be variable with a large amplitude of close to 1 magnitude, in the R band, and a short period of 12.37 min. We confirm this period and interpret it as the spin period of the white dwarf. The optical spectrum shows emission lines from hydrogen and helium superposed on a featureless continuum. The continuum changes shape throughout a cycle, such that it is redder when the source is bright. There is tentative evidence for Doppler shifts in the emission lines during the spin cycle with an amplitude of a few tens of km s$^{-1}$. Notably, the H$α$ and H$β$ lines exhibit different radial velocity amplitudes, suggesting that they come from different emission regions. We also identify a candidate orbital period of 1.00 hr, based on potential orbital sidebands. These features - Doppler shifts modulated at the spin frequency, brightness variations, and continuum shape changes - are consistent with the accretion curtain model, in which material is funneled from a truncated inner disc along magnetic field lines onto the magnetic poles of the white dwarf.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06331
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Phase-resolved optical spectroscopy of the rapidly varying white dwarf ZTF 1851+1714
Pedersen, C. C.
Knudsen, M. R. M.
Valeckas, K.
Izzo, L.
Tauris, T. M.
Fynbo, J. P. U.
Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
We report on phase-resolved optical spectroscopy and photometry in the R and B bands of the white dwarf candidate ZTF 185139.81+171430.3. The source has been reported to be variable with a large amplitude of close to 1 magnitude, in the R band, and a short period of 12.37 min. We confirm this period and interpret it as the spin period of the white dwarf. The optical spectrum shows emission lines from hydrogen and helium superposed on a featureless continuum. The continuum changes shape throughout a cycle, such that it is redder when the source is bright. There is tentative evidence for Doppler shifts in the emission lines during the spin cycle with an amplitude of a few tens of km s$^{-1}$. Notably, the H$α$ and H$β$ lines exhibit different radial velocity amplitudes, suggesting that they come from different emission regions. We also identify a candidate orbital period of 1.00 hr, based on potential orbital sidebands. These features - Doppler shifts modulated at the spin frequency, brightness variations, and continuum shape changes - are consistent with the accretion curtain model, in which material is funneled from a truncated inner disc along magnetic field lines onto the magnetic poles of the white dwarf.
title Phase-resolved optical spectroscopy of the rapidly varying white dwarf ZTF 1851+1714
topic Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2510.06331