Chromospheric activity on late-type star DM UMa using high-resolution spectroscopic observations
arXiv:1611.07395 · doi:10.1093/mnras/stw668
Abstract
We present new 14 high-resolution echelle spectra to discuss the level of chromospheric activity of DM UMa in {He I} D3, {Na I} D1, D2, Halpha, and {Ca II} infrared triplet lines (IRT). It is the first time to discover the emissions above the continuum in the {He I} D3 lines on 2015 February 9 and 10. The emission on February 9 is the strongest one ever detected for DM UMa. We analysed these chromospheric active indicators by employing the spectral subtraction technique. The subtracted spectra reveal weak emissions in the {Na I} D1, D2 lines, strong emission in the Halpha line, and clear excess emissions in the {Ca II} IRT lines. Our values for the EW8542/EW8498 ratio are on the low side, in the range of 1.0-1.7. There are also clear phase variations of the level of chromospheric activity in equivalent width (EW) light curves in these chromospheric active lines (especially the Halpha line). These phenomena might be explained by flare events or rotational modulations of the level of chromospheric activity.
8 pages, 10figures
References in corpus (5)
- A catalog of chromospherically active binary stars (third edition)
- Spots, plages, and flares on lambda Andromedae and II Pegasi
- Photospheric and chromospheric activity in four young solar-type stars
- Multiwavelength optical observations of chromospherically active binary systems V. FF UMa (2RE J0933+624): a system with orbital period variation
- Magnitude-range brightness variations of overactive K giants