Date

Speaker

Title

Jan 21

Edward Robinson

University of Texas at Austin

Organizational meeting.

Jan 28

No talk scheduled.

Feb 4

Aaron J. Juarez

University of Texas at Austin

"The Lithium Depletion Boundary Age of Blanco 1 Including the Effects of Magnetic Activity"

The lithium depletion boundary (LDB) is a robust method for accurately determining the ages of young clusters, but most pre-main-sequence models used to derive LDB ages do not include the effects of magnetic activity on stellar properties. In light of this, we present results from our spectroscopic study of the very-low-mass members of the southern open cluster Blanco 1 using the Gemini-North Telescope. We obtained Gemini Multi-Object Spectrograph spectra at intermediate resolution for cluster candidate members with I ~ 13-20 mag. From our sample of 43 spectra, we find 14 probable cluster members by considering proximity to the cluster sequence in an I/I - Ks color-magnitude diagram, agreement with the cluster's systemic radial velocity, and magnetic activity as a youth indicator. We systematically analyze the H-alpha and Li features and update the LDB age of Blanco 1 to be 126+13-14 Myr. Our new LDB age for Blanco 1 shows remarkable coevality with the benchmark Pleiades open cluster. Using available empirical activity corrections, we investigate the effects of magnetic activity on the LDB age of Blanco 1. Accounting for activity, we infer a corrected LDB age of 114+9-10 Myr. This work demonstrates the importance of accounting for magnetic activity on LDB inferred stellar ages, suggesting the need to reinvestigate previous LDB age determinations.

close

Feb 11

Phillip MacQueen

McDonald Observatory

"The New HET High Resolution Spectrograph"

Feb 18

Matthew Shetrone

McDonald Observatory

"APOGEE: The SDSS High Resolution H-band Survey of Milky Way Bulge, Disk and Halo on out to M31 Globular Clusters"

Feb 25

Keaton Bell

University of Texas at Austin

"Pulsations in the Lowest-Mass White Dwarfs: Recent Discoveries and Ensemble Properties"

Mar 4

Natalie Gosnell

University of Texas at Austin

"The Story of Strange Binaries: Blue Straggler Stars in Old Open Clusters"

Mar 11

Anita Cochran

University of Texas at Austin

"Hot Facts About Cool Comets"

Mar 18

No talk scheduled. Spring Break: 16-20 March.

Mar 25

No talk scheduled.

Apr 1

David Lambert

University of Texas at Austin

"The Hercules Stream"

Apr 8

Andrew Mann

University of Texas at Austin

"The Radii of M-dwarf Stars"

Apr 15

G. Fritz Benedict

University of Texas at Austin

"Mass-Luminosity Relations for M-Dwarf Stars"

Apr 22

No talk scheduled.

Apr 29

No talk scheduled.

May 6

Harriet Dinerstein

University of Texas at Austin

"New Emission Lines of Neutron-Capture Elements Disovered with IGRINS"