The unusual X-ray and EUV flare activity of Wolf 630AB

• Published in: Monthly notices of the Royal Astronomical Society Vol. 308; no. 1; pp. 111 - 118
• Main Authors: Kellett, B. J., Tsikoudi, V.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.09.1999
• Subjects: stars: activity; stars: flare; stars: individual: Wolf 630AB; stars: late-type; X-rays: stars; stars: flare; X-rays: stars; stars: late-type; stars: activity; stars: individual: Wolf 630AB
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1046/j.1365-8711.1999.02718.x

We study the X-ray and extreme ultraviolet (EUV) behaviour of the flare star Wolf 630AB (V1054 Oph, Gl 644AB, HD 152751) using the ROSAT all-sky survey data from 1990 August. The simultaneous X-ray and EUV observations revealed a complex and unusual series of interplay. Indeed, the star was in a state of almost continuous flare activity for the two days of the X-ray observations. We saw a total of five X-ray flares (plus a subflare) and at least as many flares were also seen in the EUV data. We suggest that the series of flares observed on Wolf 630AB originated in a single (probably complex) active region and illustrate, in a unique way, the evolution of flare activity in the stellar corona of a very active dMe star.