Central Michigan University

Past Seminars

• Thursday, March 20 4:00pm (Dow 107)
  Dr. Dana E. Backman, SOFIA and the SETI Institute

  
  

  Nearby Stars and Debris Disks: A Ringside Seat to Planet Formation

  
  Astronomers have discovered disks of gas and dust around many young stars that may be the sites of ongoing planet formation. Some nearby older stars are surrounded by rings and disks of material that are probably remnants of planet formation processes. These so-called "debris disks" have sizes and structures resembling the Kuiper Belt of icy objects orbiting beyond Neptune in our solar system. Current observations of debris disks by Earth- and space-based observatories will be reviewed, including signs of the gravitational influence of large planets on the disk morphologies. Future observations of these systems by SOFIA (Stratospheric Observatory for Infrared Astronomy) are expected to provide better evidence of the presence of planets associated with the debris disks.
  
  Host: Chris Tycner
  

• Wednesday, March 19 7:00pm (Dow 171)
  Dr. Dana E. Backman, SOFIA (Stratospheric Observatory for Infrared Astronomy) and the SETI Institute

  
  

  Harlow Shapley Public Astronomy Lecture:

  Looking for Life in All the Right Places: An Astrobiological Tour of the Solar System

  
  As soon as the Copernican revolution made humanity aware that the Earth is one planet among many, speculation began about the possibility that other planets might be inhabited. The main focus of interest always has been Mars, with the most Earth-like surface conditions of any planet. Rovers Spirit and Opportunity have found clear evidence that Mars was once wetter and warmer than at present. In addition, Viking Mars lander soil test results from the 1970s indicated possible biological activity, and some investigators believe Mars rock ALH84001 contains fossil microbes plus their metabolic products. Beyond Mars, there is evidence for liquid water under ice crusts on Jupiter's moons Europa and Ganymede and Saturn's moon Enceladus, as well as abundant organic compounds in the atmosphere and on the surface of Saturn's moon Titan. Could any of these worlds harbor Earth-like, water-and-carbon-based life? Astrobiology research and planetary exploration may reveal answers within just a few decades.
  
  Host: Chris Tycner
  

• Thursday, February 28 4:15pm (Dow 107)
  Veronica Barone, Department of Physics, Central Michigan University

  
  

  Graphene Nanoribbons: The Rising Star in Nanomaterials Research

  
  Graphene-based materials have emerged as one of the most promising candidates for the new generation of electronic devices. Here, we will discuss the rich variety of electronic properties displayed by different types of the so-called graphene nanoribbons. These ribbons are narrow strips of graphene that exhibit electronic behavior similar to that of carbon nanotubes. However, unlike nanotubes, carbon nanoribbons can be produced in a much more controllable manner. Despite this great advantage, their exotic electronic and magnetic properties depend strongly on the nature of the edges that are characteristic of these systems. We will present results of our first-principles calculations of the electronic properties of these materials, considering pristine and functional groups at the edges. We will also explore the electronic properties of other multi-component hexagonal networks.
  
  Host: Juan Peralta
  Cookies and coffee: 3:45pm in Dow 201.

• Thursday, February 07 4:00pm (Dow 107)
  Dr. Erika Grundstrom, Vanderbilt University

  
  

  RY Scuting Along: Studying a Messy Binary

  
  A long time ago in a binary far, far away, one star was growing while another was shrinking. Even though this actually happened 7000 years ago, the light from these events in the RY Scuti binary is just getting to us. Right now we see one star dumping some of its mass onto its companion - active mass transfer and a messy transfer at that. I'll show you how we gleaned information about the two stars (such as masses) and determined that there is a 2000 A.U. double-ring nebula and a 1 A.U. circumbinary disk around the two stars, gas leaking from L2, and an accretion torus around the mass gainer. Eventually, one or both of these stars will go supernova.
  
  Host: Chris Tycner
  

• Thursday, January 10 4:00pm (Dow 107)
  Krzysztof Starosta, Michigan State University

  
  

  Recoil Distance and Doppler Shift Attenuation Lifetime Measurements at NSCL

  
  Transition rate were measured recently for the first and the second 2+ states in N=Z 64Ge, far from the line of nuclear stability. The experimental results are in excellent agreement with large-scale Shell Model calculations applying the recently developed GXPF1A interactions. The measurement was done using the Recoil Distance Method (RDM) and a unique combination of state-of-the-art instruments at the National Superconducting Cyclotron Laboratory (NSCL). States of interest were populated via an intermediate-energy single-neutron knock-out reaction. RDM and related Doppler Shift Attenuation studies of knock-out and fragmentation reaction products hold the promise of providing lifetime information for excited states in a wide range of unstable nuclei. Physics applications of both methods will be presented and discussed.
  
  Host: Mihai Horoi