Thomas M. Boudreaux Thesis Proposal

Models of Low Mass Stars in the Local Solar Neighborhood and in Globular Clusters

Thomas M. Boudreaux

Brian Chaboyer, Elisabeth Newton, & Aaron Dotter

Low Mass Stars

~~Low~~ Lower Mass Stars

Initial Mass Function

Main Sequence Lifetime

Stellar Populations

This Thesis

Jao Gap

Globular Clusters

First Paper

Jao Gap

~17% drop in density around Mag 10
Asymmetric production of Helium in ppI chain

Jao Gap

Convective Kissing Instability

Jao Gap

Convective Kissing Instability

Jao Gap

Convective Kissing Instability

Jao Gap

Convective Kissing Instability

Jao Gap

Star near the convective transition mass

Jao Gap

The Jao Gap Lets Us Probe the Interior Structure of M Dwarfs

Jao Gap

The mass where the gap occurs is a function of metallicity

\[\begin{align} \nabla_{rad} \propto \frac{L\kappa}{T^{4}} \end{align}\]

DSEP uses OPAL opacity tables

~25 Years Old
Difficult to query

OPLIB

LTE/Non-LTE plasma modeling code from Los Alamos
Based on ATOMIC (Magee+ 2004)

Jao Gap With OPLIB

Jao & Feiden 2021 Identify some substructure with the observed Gap

Second Paper

Jao Gap Age Dependence

The Jao Gap's Location Evolves with Age

Jao Gap Age Dependence

Time evolution of interior of a star within the mass range of the Jao Gap

Jao Gap Age Dependence

Which Populations?

Synthetic population around the Jao Gap

Age-Dating

Clusters

Solar Neighborhood

Populations of different ages tend to have different kinematics

Age-Dating

Difficulties

Binarity

Variations in Metallicity

Kinematic Ages

Difficulties

All these effects smear the Jao Gap

Third Paper

Theory \(\rightarrow \) Application

Gaia Catalogue of Nearby Stars

\(>\)95% Complete for all stars earlier than M8 within 100 pc

Cleaned of spurious sources

331312 sources

7654 sources within a tight band around the Jao Gap

MEARTH & Lu + 2021

Radial Velocities

Rotational Periods

Rossby Numbers

New Age Indicator?

Globular Clusters

Fourth Paper

Globular Clusters

Extremely Clean CMD
- Similar distances
- Similar ages
- Similar compositions

Globular Clusters

NGC 2808

Globular Clusters

Formation Channels

Globular Clusters

asymtotic giant branch stars

Globular Clusters

asymtotic giant branch stars
fast rotating massive stars

Globular Clusters

asymtotic giant branch stars
fast rotating massive stars
super massive stars

Globular Clusters

asymtotic giant branch stars
fast rotating massive stars
super massive stars
massive interacing binaries

Helium Cannot be Observed in GCs Effectively

NGC 2808

Chemical Consistency...

Model multiple populations with self consistent opacities
Atmospheric consistency

DSEP uses OPAL opacity tables

~25 Years Old
Difficult to query

NGC 2808

MARCS Model Atmospheres for Populations A & E

Photometric Calibration

Do we believe the photometry?

Renata Edaes Hoh

Fifth Paper

Other Clusters

NGC 6752 & 47 Tuc

NGC 6752

Dotter+2015 Self-consistently modeled NGC 6752

NGC 6752

Dotter+2015 Self-consistently modeled NGC 6752

Sensitivity to UV portions of atmospheric models

Timeline

Five Papers over the next two years

Significant work for two completed

With Thanks too

Brian
Elisabeth
Aaron
My peers & friends

?

Bjork, S. R., & Chaboyer, B. 2006, ApJ, 641, 1102, doi: 10.1086/500505
Chaboyer, B., Fenton, W. H., Nelan, J. E., Patnaude, D. J., & Simon, F. E. 2001, ApJ, 562, 521, doi: 10.1086/323872
Colgan, J., Kilcrease, D. P., Magee, N. H., et al. 2016, in APS Meeting Abstracts, Vol. 2016, APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts, D1.008
Dotter, A., Chaboyer, B., Jevremović, D., et al. 2008, The Astrophysical Journal Supplement Series, 178, 89
Feiden, G. A., Skidmore, K., & Jao, W.-C. 2021, ApJ, 907, 53, doi: 10.3847/1538-4357/abcc03
Jao, W.-C., & Feiden, G. A. 2021, 5, 124, doi: 10.3847/2515-5172/ac053a
Jao, W.-C., Henry, T. J., Gies, D. R., & Hambly, N. C. 2018, ApJL, 861, L11, doi: 10.3847/2041-8213/aacdf6
Mansfield, S., & Kroupa, P. 2021, A&A, 650, A184, doi: 10.1051/0004-6361/202140536
Lu, Y. L., Angus, R., Curtis, J. L., David, T. J., and Kiman, R., “Gyro-kinematic Ages for around 30,000 Kepler Stars”, The Astronomical Journal, vol. 161, no. 4, 2021. doi:10.3847/1538-3881/abe4d6.

OPLIB vs. OPAL

Calibrated Solar Models

Changes on the order of 1%

MESA and YREC models

YREC models