ﻻ يوجد ملخص باللغة العربية
Flares are known to play an important role for the evolution of the atmospheres of young planets. In order to understand the evolution of planets, it is thus important to study the flare-activity of young stars. This is particularly the case for young M-stars, because they are very active. We study photometrically and spectroscopically the highly active M-star 2MASS J16111534-1757214. We show that it is a member of the Upper Sco OB association, which has an age of 5-10 Myrs. We also re-evaluate the status of other bona-fide M-stars in this region and identify 42 members. Analyzing the K2-light curves, we find that 2MASS J16111534-1757214 has, on average, one super-flare with E > 1.0E35 erg every 620 hours, and one with E >1.0E34 erg every 52 hours. Although this is the most active M-star in the Upper Sco association, the power-law index of its flare-distribution is similar to that of other M-stars in this region. 2MASS J16111534-1757214 as well as other M-stars in this region show a broken power-law distribution in the flare-frequency diagram. Flares larger than E >3E34 erg have a power-law index beta=-1.3+/-0.1 and flares smaller than that beta=-0.8+/-0.1. We furthermore conclude that the flare-energy distribution for young M-stars is not that different from solar-like stars.
We aim at identifying very low-mass isolated planetary-mass member candidates in the nearest OB association to the Sun, Upper Scorpius (145 pc; 5-10 Myr), to constrain the form and shape of the luminosity function and mass spectrum in this regime. We
We present detailed modeling of the spatial distributions of gas and dust in 57 circumstellar disks in the Upper Scorpius OB Association observed with ALMA at sub-millimeter wavelengths. We fit power-law models to the dust surface density and CO $J$
The Upper Scorpius OB association is the nearest region of recent massive star formation and thus an important benchmark for investigations concerning stellar evolution and planet formation timescales. We present nine EBs in Upper Scorpius, three of
We present the results of photometric and spectroscopic follow-ups of the lowest mass member candidates in the nearest OB association, Upper Scorpius (5-10 Myr; 145+/-17 pc), with the Gran Telescopio de Canarias (GTC) and European Southern Observator
Proper motion measurements of the cool and ultracool populations in the Upper Scorpius OB association are crucial to confirm membership and to identify possible run-away objects. We cross-match samples of photometrically selected and spectroscopica