Magnetic Activity of Pre-main Sequence Stars
نویسندگان
چکیده
منابع مشابه
Magnetic flaring in pre-main sequence stars
Observations of nearby star forming clouds with imaging Xray telescopes have revealed that X-ray emission is elevated 10 − 10 above main sequence levels in low-mass pre-main sequence (PMS) stars. The variability and spectral X-ray evidence, together with circularly polarized radio continuum flares seen in a few cases, strongly argues for an origin in magnetic reconnection flares. These high lev...
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Rotation and activity are key parameters in stellar evolution and can be used to probe basic stellar physics. Here we present a study of rotation (measured as projected rotational velocity v sin i) and chromospheric activity (measured as Hα equivalent width) based on an extensive set of high-resolution optical spectra obtained with the MIKE instrument on the 6.5m Magellan Clay telescope. Our ta...
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The study of pre-main sequence stellar coronae is undertaken in many different wavelength regimes, with apparently conflicting results. X-ray studies of T Tauri stars suggest the presence of loops with a range of sizes ranging from less than a stellar radius to 10 stellar radii. Some of these stars show a clear rotational modulation in X-rays, but many do not and indeed the nature of this emiss...
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The position of pre-main-sequence or protostars in the Hertzsprung–Russell diagram is often used to determine their mass and age by comparison with pre-main-sequence evolution tracks. On the assumption that the stellar models are accurate, we demonstrate that, if the metallicity is known, the mass obtained is a good estimate. However, the age determination can be very misleading because it is s...
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This review covers the properties of disks around pre-main– sequence stars. It is at this time in the evolution that planets form, and it is important to understand the properties of these disks to understand planet formation. I discuss disk shapes, masses and temperatures, the properties of the host stars, disk lifetimes and dissipation processes. Finally, evidence of grain growth during pre-m...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 2004
ISSN: 0074-1809
DOI: 10.1017/s0074180900182130