1. Importance:
• Ages set timescales for
stellar and planetary
evolution
• Timescale for giant planet
formation
• Angular momentum
evolution
• Disk evolution
Data:
• Li equivalent widths (EW (Li))
from various sources
(e.g., Torres et al. 2006,
Fernandez et al. 2008)
• Trigonometric Distances
(Weinberger et al. 2012,
Ducourant et al. 2014, van
Leeuwen 2007)
• J band magnitudes from
2MASS
• Spectral types from various
sources (e.g., Pecaut and
Mamajek 2013, Torres et al.
2006)
References:Palla, Randich, Pavlenko, Flaccomio, Pallavicini, 2007, ApJ, 659, 41
Torres, Quast, da Silva, de La Reza, Melo, Sterzik, 2006 A&A, 460, 695
Fernandez, Figueras, Torra, 2008, A&A, 480, 735
Pecaut & Mamajek, 2013, ApJS, 208, 9
Weinberger, Anglada-Escude, Boss, ApJ, 762, 118
Soderblom, Jones, Balachandran, Stauffer, Duncan, Fedele, Hudon, 1993, AJ, 106, 1059
Yee & Jensen, 2010, 711, 303
Van Leeuwen, 2007, A&A, 474, 653
Binks & Jeffries, 2014, MNRAS, 438, 11
Mentuch, Brandeker, van Kerwijk, Jayawardhana, Hauschildt, 2008, ApJ, 689, 1127
Ducourant, Teixeira, Galli, Le Campion, Krone-Martins, Zuckerman, Chauvin, Song, 2014, A&A,
563,121
Kastner, Zuckerman, Weintraub, Forveille, 1997, Science, 277, 67
Results:
• Preliminary results indicate TWA is ~5-8 Myr
• This age is younger than previously thought
What is TWA?
• The TW Hydrae Association
(TWA) is the youngest (~10
Myr; Barrado Navascués et
al. 2006) nearby (~50 pc;
Weinberger et al. 2012)
group of stars
Goal:
• Determine the Lithium
depletion age of the TW
Hydrae association
Methods:
• Calculated luminosities and
Li abundances
• Compared to Baraffe et al.
2015 Evolutionary Tracks
New Curve of Growth:
• Built curve of growth using
Synth3 (Kochukhov et al.
2012) and Robospect (Z.
Waters & K. Hollek et al.
2013)
• Data compiled from
continuous Teff[K] 2500-
4250, various log(g) and
A(Li) values calculated by
Caffau (et al. 2011)
Lithium Depletion Age of
The TW Hydrae Association
Katie J. Boyce, Mark J. Pecaut
Rockhurst University, Kansas City, MO 64110