Active cool stars and He I 10 830 Å: the coronal connection

• Published in: Astronomy and astrophysics (Berlin) Vol. 488; no. 2; pp. 715 - 721
• Main Authors: Sanz-Forcada, J., Dupree, A. K.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.09.2008
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; infrared: stars; line: formation; stars: activity; stars: chromospheres; stars: late-type; X-rays: stars; Late type stars; Recombination; High density; Equivalent width; Luminosity; Cool star; Spheres; Triplets; Continuum; stars: chromospheres; Giant stars; Dynamics; Stellar chromospheres; Infrared radiation; Excitation; stars: activity; Infrared star; Gravity; Photoexcitation; X-rays: stars; infrared: stars; Line formation; Subgiant star; Radiation absorption; line: formation; Photoionization; stars: late-type; Correlations; Dwarf stars; Stellar activity; Formation mechanism; Recombination process

Context. The mechanism of formation of the He I 10 830 Å triplet in cool stars has been subject of debate for the last 30 years. A relation between the X-ray luminosity and the He I 10 830 Å flux was found in cool stars, but the dominant mechanism of formation in these stars (photoionization by coro...