Determining the Membership of Globular Cluster, M2 with APOGEE Data

VA-NC Alliance Summer Research Program

The Leadership Alliance National Symposium

July 29th , 2017

BY: ZANIYAH DOCK

What’s the point?

• We are trying to understand the building blocks of the Milky Way Galaxy.

• Star clusters are physically associated groups of stars, held together permanently or temporarily

by their mutual gravitational attraction. They help us:

• Explore models of stellar evolution and the star formation process

• Measure the age and evolution of the Galaxy

• This project specializes in a specific type of star cluster, Globular Clusters.

What is a Globular Cluster? And why use them?

• Globular Clusters are a type of star cluster. Globular Clusters are made up of relatively old stars.• Known Globular clusters in our galaxy are about 147.

• Located in a almost nearly spherical distribution, being the most visible part of the Galactic

Halo.

• Their Importance: We expect that Globular Clusters are simple stellar systems, where stars are

born from a birth cloud of a given metal content. Therefore we can analyze this metal content, as

well as a different parameters in order to determine the membership a star should have if

belonging to a particular cluster.

M2

National  Optical  Astronomy  Observatory  

How we’re determining this membership…. Parameters:

• Log g: Surface gravity can give us how big the star is

• [Fe/H]: iron to hydrogen ratio

• [Alpha/M]: ratio of helium captured elements to metallicity

• Radial Velocity: whether the star is moving toward or away from us

Results

Results

Results

Conclusions

•Application (Why use this project or experiment) :

• Tidal Disruption and being able to observe potential examples of a star cluster being pulled

apart.

• This project can be isn’t specific to one star system. Any star system can be used in this

manner.

• The next step of this project would be to further analyze this cluster with more parameters,

given that it is a good candidate of Tidal Disruption.

Acknowledgements

• Department of Astronomy at University of Virginia

• Mentors: Nitya Kallivayalil, Shane Davis and Paul Zivick ; Colleague: Temitope Olatinwo

• NSF: This work was supported by the NSF CAREER award 1455260

• SDSS: SDSS  Acknowledgment: Funding  for  the  Sloan  Digital  Sky  Survey  IV  has  been  provided  by  the  Alfred  P.  Sloan  Foundation,  the  U.S.  Department  of  Energy  Office  of  Science,  and  the  Participating  Institutions.  SDSS-­‐IV  acknowledges  support  and  resources  from  the  Center  for  High-­‐Performance  Computing  at  the  University  of  Utah.  The  SDSS  web  site  is www.sdss.org.

SDSS-­‐IV  is  managed  by  the  Astrophysical  Research  Consortium  for  the  Participating  Institutions  of  the  SDSS  Collaboration  including  the  Brazilian  Participation  Group,  the  Carnegie  Institution  for  Science,  Carnegie  Mellon  University,  the  Chilean  Participation  Group,  the  French  Participation  Group,  Harvard-­‐Smithsonian  Center  for  Astrophysics,  Instituto de  Astrofisica de  Canarias,  The  Johns  HopkinsUniversity,  Kavli Institute  for  the  Physics  and  Mathematics  of  the  Universe  (IPMU)  /  University  of  Tokyo,  Lawrence  Berkeley  National  Laboratory,  Leibniz  Institut fur  Astrophysik Potsdam  (AIP),  Max-­‐Planck-­‐Institut fur  Astronomie (MPIA  Heidelberg),  Max-­‐Planck-­‐Institut fur  Astrophysik (MPA  Garching),  Max-­‐Planck-­‐Institut fur  ExtraterrestrischePhysik (MPE),  National  Astronomical  Observatory  of  China,  New  Mexico  State  University,  New  York  University,  University  of  Notre  Dame,  Observatario Nacional /  MCTI,  The  Ohio  State  University,  Pennsylvania  State  University,  Shanghai  Astronomical  Observatory,  United  Kingdom  Participation  Group,  Universidad  Nacional AutonomadeMexico,  University  of  Arizona,  University  of  Colorado  Boulder,  University  of  Oxford,  University  of  Portsmouth,  University  of  Utah,  University  of  Virginia,  University  of  Washington,  University  of  Wisconsin,  Vanderbilt  University,  and  Yale  University.

• Spelman College

• University of Virginia

• VA-NC Alliance Summer Research Program