Follow-up optical linear polarimetric observations of WW Lyn

ATel #17759; Nicolaus Steenken (Sternwarte Freimann), Jan-Uwe Ness (ESA)
on 19 Apr 2026; 09:35 UT
Credential Certification: Jan-Uwe Ness (jan.uwe.ness@esa.int)

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Following the report of increased X-ray activity in the Cataclysmis Variable WW Lyn in ATel#17749, a polarimetric observation was conducted on 2026-04-17 (JD 2461148.34). An 11 inch Schmidt-Cassegrain Telescope in Munich was used equipped with a calibrated Dual Beam Polarimeter described in Nielsen et al., 2023, A&A, 677, A96 and Steenken et al., 2025 Res. Notes AAS 9 36. The data consist of a total of 120 individual frames, with 30 images acquired at each of the four half-wave plate (HWP) positions. Each frame had an exposure time of 10 seconds. The V-band measurements yield a debiased linear polarization for the target star of P=0.0 +/- 0.15% (1-sigma), consistent with no measurable linear polarisation. For comparison, the field star TYC2958-1801-1 (V=10.1 mag), measured in the same field of view, shows a V-band polarization of P=0.18% +/- 0.07% and PA=145 +/- 20 deg. This is consistent with the expected low interstellar polarization in this direction.