Eric Mamajek (JPL/Caltech, University of Rochester), Lynne Hillenbrand, Robin Jeffries
9/19/17, 4:15 PM
88. Testing the accuracy of pre-main sequence stellar models with rotation, inflation, and lithium abundances
Garrett Somers (Vanderbilt University)
9/19/17, 4:30 PM
Accurate ages of young (≤ 100 Myr), solar-type stars are of central importance to many questions in stellar astrophysics. But current methods for dating these objects remain imprecise and mutually contradictory. Perhaps the most reliable method for cluster dating is the lithium depletion boundary technique, however the precision of individual Li-based stellar ages remains limited. An...
Gregory Herczeg (KIAA/Peking University)
9/19/17, 5:30 PM
Ages of pre-main sequence stars are notoriously uncertain, with implications for measurements of envelope and protoplanetary disk survival times and for quantifying star formation histories. In any given cluster, a spread of apparent ages may be caused by individual differences in stellar evolution, by observational errors, or by a real age spread. The ages of intermediate-mass and low-mass...
Giuseppe Sacco (INAF - Osservatorio di Arcetri)
9/19/17, 6:00 PM
Age and masses of pre-main sequence stars are traditionally derived from photometric data using multi-band color-magnitude diagrams and evolutionary models. However, ages derived with this method are affected by several empirical errors not easy to estimate (binary, extinction/reddening, photometric variability, on going accretion, presence of protostellar disks) and depend on the modeling of...
Konstanze Zwintz (University of Innsbruck)
9/19/17, 6:30 PM
Age is a fundamental tool to understand different phenomena in stellar astrophysics. But in the pre-main sequence (pre-MS) stages, the errors in age can be up to 100% as for example the ages of young clusters are typically given as 5 +/- 5 Myr. Asteroseismology of pre-MS stars can be used as a novel age indicator because the pulsations provide an observable that is changing sensitively and...
Richard Jackson (Keele University)
9/19/17, 6:45 PM
The radius of a star is a critical output of stellar models. It sets the effective temperature at a given luminosity and hence the age of PMS stars inferred from their positions in the HR diagram. Observations of low mass binaries show that standard models under-estimate stellar radii; the suggested cause being magnetic activity inhibiting convection and/or blocking surface flux due to star...
9. Planet ingestion on a pre-main sequence star: the case of 2MASS J08095427−4721419 in the Gamma Velorum cluster.
Emanuele Tognelli (Università di Pisa/INFN)
9/19/17, 7:00 PM
We performed a theoretical study of the effects of planet ingestion on the characteristics of a pre-MS star. We applied our analysis to the case of the Gamma Velorum cluster member 2MASS J08095427−4721419, which shows a peculiar over-abundance of metals with respect to the other cluster members. We analyzed the effects on the star of changing the characteristic of the accretion episode, namely...
Markus Janson (Stockholm University)
9/19/17, 7:15 PM
Young moving groups (YMGs) are fundamentally important for constraining ages and evolutionary processes of young stars. As a consequence, constraining the ages of the groups themselves is of high priority. M-type stars offer an interesting path for this, since they remain in the pre-MS phase for ~100 Myr, comparable to the ages of YMGs, and thus are suitable for isochronal analysis. Dynamical...