Letter to the Editor Li I enhancement during a long-duration stellar flare

Li i enhancement during a long - duration stellar flare

We report the possible detection of a Li i λ6708 Å line enhancement during an unusual long-duration optical flare in the recently discovered, X-ray/EUV selected, chromospherically active binary 2RE J0743+224. The Li i equivalent width (EW) variations follow the temporal evolution of the flare and large changes are observed in the intensity of the line. The maximum Li i enhancement (40% in EW) o...

ar X iv : a st ro - p h / 98 09 11 8 v 1 9 S ep 1 99 8 A long - duration flare

2RE J0743+224 (BD +23 1799) is a chromospherically active star selected by X-rays and EUV emission detected in the Einstein Slew Survey and ROSAT Wide Field Camara (WFC) all sky survey, and classified as single-lined spectroscopic binary by (Jeffries et al. 1995). We present here high resolution echelle spectroscopic observations of this binary, obtained during a 10 night run 12-21 January 1998...

Detection of Li i enhancement during a long - duration flare in the recenltly discovered X - ray / EUV selected , chromospher - ically active binary 2 RE J 0743 + 224

Letter to the Editor Periodic changes of veiling and circumstellar grey extinction in DF Tauri I. Dust clouds spiraling into a T Tauri star?

We present 110 simultaneous BV I photometric measurements and low resolution (≈ 400) spectra obtained during 17 consecutive days on the Classical T Tauri star DF Tau. Applying a new method for veiling extraction from low resolution spectra, we derive veiling curves in the B and V photometric bands which closely resemble their corresponding light curves. Analysis of the combined light and veilin...

Optical and UV observations of a strong flare in the young , single K 2 - dwarf LQ Hya ⋆

We present high resolution optical echelle spectra and IUE observations during a strong flare on 1993 December 22 in the very active, young, rapidly rotating, single K2 dwarf LQ Hya. The initial impulsive phase of the flare, which started sometime between 2:42 UT and 4:07 UT, was characterized by strong optical continuum enhancement and blue-shifted emission lines with broad wings. The optical ...