Titlebook: Open Issues in Local Star Formation; Jacques Lépine,Jane Gregorio-Hetem Conference proceedings 2003 Springer Science+Business Media Dordre

Ccu106

The Stellar Mass Function of Galactic Clusters and Its Evolution with an exponential truncation of the form . α .. [1−exp(−..).]. The average value of the power-law index α is very close to Salpeter (∼ 2.3), whereas the peak mass .. is in the range 0.1–0.6 M. and does not seem to vary in a systematic way with the present cluster parameters such as metal abundanc

确定的事

Encounters and Close Fly-Bys of Galactic Clusters and Associations in the Past 50 Myrolecular cloud may be directly impacted by the gas in another cloud upon a cloud-cloud collision (Lépine & Duvert 1994) or it may be shocked by bubbles blown up by stellar winds and supernova explosions in a chance fly-by OB association (de Geus 1991). Clues of such events during the last 50 Myr are

谆谆教诲

Solar-Type Post-T Tauri Stars in the Nearest OB SubgroupsB subgroups by Mamajek, Meyer, & Liebert (2002, AJ, 124, 1670). LCC and UCL are subgroups of the Sco-Cen OB association, and the two nearest OB subgroups to the Sun. In the entire survey of 110 pre-main sequence stars, there exists only one Classical T Tauri star (PDS 66), implying that only ∼1% of

材料等

Systemic

implore

The Oph-Sco-Lup-Cen-Cru-Mus-Cha Star-formation Regionamaeleon, is discussed. We consider that a satisfactory model must be able to explain the main properties of these associations, like the spatial distribution of the stars, the geometry of the interstellar clouds, the space velocities and age distribution of the premain sequence (PMS) and OB stars.

Fatten

hedonic

Between

Age Determination of the Ursa Major Associationrs. The age derived for the association ranges between 200 to 500 Myr where the canonical age is 300 Myr derived by Soderblom & Mayor (1993). More recent age determinations are from König et al. (2002) who derive an age of 100±30 Myr based on Baraffe et al. (1998) pre-main-sequence models and from K

Tonometry

Accretion Powered Emission in Young Stellar Objectsn, ∼ 0.03M. — ∼ 5M., and show corresponding mass accretion rate determination over this mass range. We find that the mass accretion rate M increases with stellar mass M., roughly asÿ M ∝ M.. The physical principles behind this correlation are unknown at present; they must involve mechanisms for tran