v410 tau t tauri pre main sequence – young, low mass stars that are contracting as they evolve...
TRANSCRIPT
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V410 TAU
T TAURI
• Pre Main Sequence – young, low mass stars that are contracting as they evolve toward their main sequence stage.
• Mostly made of Hydrogen, some Helium, and some trace elements. Of the trace elements, Lithium appears which is an indicator of stellar youth.
• Often have large protoplanetary accretion disks left over from stellar formation.
• Typical size and age: 0.2-3x’s Solar Mass and 100,000 – 1,000,000 years• Found in galactic clouds (like Taurus Auriga dark cloud) because they formed
more recently and haven’t had enough time to move far from where they formed.
• Spectra contain strong Balmer lines as well as forbidden lines … and … . The low density of T Tauri stars allows these lines to appear.
Analysis of MOST light curves of five young stars in Taurus–Auriga and Lupus 3 star-forming regions†
Michal Siwak, Slavek M. Rucinski, Jaymie M. Matthews, Rainer Kuschnig, David B. Guenther, Anthony F. J. Moffat, Dimitar Sasselov, Werner W. WeissArticle first published online: 29 JUN 2011
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• Unlike many other types of variable stars, the behavior of T Tauri young stars is very erratic.
• The variations in light of these stars are so irregular and unpredictable that classification of T Tauri variables cannot be based upon their light-curves.
• Between 1864 and 1916, the brightness magitude of T Tauri was between 9.3 and 14.
• In 2009 and 2010, the Canadian Microvariability and Oscillations of Stars (MOST) satellite observed V410 Tau in T Tauri system and obtained the maximum brightness magnitude of 10.8.
• Doppler tomographic studies show that the light variations of V410 Tau is due to rotational modulation by dark spots. The light curves systematic changes support the observations of spots.
• To retain consistancy with the result, MOST assumed two dark spots: one close to the pole and a second at low latitudes, and obtained the rotational period of 1.87 days.
LIGHT CURVE OF T TAURI
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• Theory: many variations in the star due to a magnetic
field
• A magnetic reconnection event
• Probability of flare detection is low
• Magnitudes of flares generally moderate in size 0.2-0.1
mag
Flares
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PROBLEMS• Some T Tauri stars have periodic non thermal radio emissions
• The long term stability of large spots is not explained by current theory
• Some T Tauri stars have dark spots that are higher in temperature than their surrounding photosphere
• The magnetic fields of T Tauri stars are not well understood, though they are believed to be similar to late Main Sequence stars
• The pattern of flare events is not well documented
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POSSIBLE SOLUTIONS• Extended Range Photometry – X-ray through Radio waves
• Better Models – both models to fit the data, to better explain the convective properties of T Tauri stars, and to model large spots
• Increased sensitivity to small spots
• Longer Studies – most current studies only record a few periods