Seth Redfield Group-White Dwarf Exoplanet Survey & Exoplanet Atmosphere Rayleigh Scattering Modeling (March 2013 - Present)
James Greenwood Group - Lunar Apatite Hydration & Chondrule Formation (January 2014 - Present)
Reinhold Blümel Group - Ion Trap Physics (August 2012 - June 2013)
Seth Redfield Group (March 2013 - Present) - White Dwarf Exoplanet Survey and exoplanet atmosphere Rayleigh Scattering Modeling
White Dwarf Exoplanet Survey
The first exoplanets discovered were orbiting a pulsar. Since then, most exoplanets have been found around main sequence stars. We are interested in detecting exoplanets orbiting a different type of compact object that forms as the final stage of stellar evolution –a white dwarf star. Because white dwarf stars have radii approximately equal to that of Earth’s, the transit of a terrestrial size planet would appear to us as a full eclipse, or a drop in flux of similarly high magnitude, depending on the planet’s inclination. As such, even small sized telescopes, which almost every university, many high schools, and multitudes of amateur astronomers possess, could be used to hunt for Earth-sized exoplanets. This would greatly increase the breadth of humans able to contribute to the search for habitable planets, familiarizing the public with an effort that is often seen as inaccessible to all but a few scientists.
Furthermore, planets in the habitable zone of these stars have orbital periods between ~5-30 hours, as opposed to a star like our Sun, where planets in the habitable zone would have orbital periods on the order of years, like Earth’s. As such, the existence of white dwarf exoplanets would allow for swift and efficient habitable exoplanets surveys to be conducted.
The Wesleyan 24” observing program is currently dedicated to this search, collecting white dwarf flux data every night that the Connecticut weather allows us to. We are also using K2 to obtain data on dozens of other white dwarfs. Collaborators with their own telescopes and CCDs are encouraged to participate in this effort! We will reduce your data for you with our currently existing IDL reduction pipeline! Please contact me or Girish Duvvuri if you are interested in participating.
My work on this project, which has since been passed on to Girish Duvvuri, is summarized in this paper, which I presented at the KNAC symposium in 2013:
The first exoplanets discovered were orbiting a pulsar. Since then, most exoplanets have been found around main sequence stars. We are interested in detecting exoplanets orbiting a different type of compact object that forms as the final stage of stellar evolution –a white dwarf star. Because white dwarf stars have radii approximately equal to that of Earth’s, the transit of a terrestrial size planet would appear to us as a full eclipse, or a drop in flux of similarly high magnitude, depending on the planet’s inclination. As such, even small sized telescopes, which almost every university, many high schools, and multitudes of amateur astronomers possess, could be used to hunt for Earth-sized exoplanets. This would greatly increase the breadth of humans able to contribute to the search for habitable planets, familiarizing the public with an effort that is often seen as inaccessible to all but a few scientists.
Furthermore, planets in the habitable zone of these stars have orbital periods between ~5-30 hours, as opposed to a star like our Sun, where planets in the habitable zone would have orbital periods on the order of years, like Earth’s. As such, the existence of white dwarf exoplanets would allow for swift and efficient habitable exoplanets surveys to be conducted.
The Wesleyan 24” observing program is currently dedicated to this search, collecting white dwarf flux data every night that the Connecticut weather allows us to. We are also using K2 to obtain data on dozens of other white dwarfs. Collaborators with their own telescopes and CCDs are encouraged to participate in this effort! We will reduce your data for you with our currently existing IDL reduction pipeline! Please contact me or Girish Duvvuri if you are interested in participating.
My work on this project, which has since been passed on to Girish Duvvuri, is summarized in this paper, which I presented at the KNAC symposium in 2013:
| whitedwarfexoplanetsurveypaperdownload.pdf |
Rayleigh Scattering Modeling and Detection of Exoplanet Atmospheres
In recent years, astronomers have learned how to characterize the chemistry of exoplanet atmospheres. The complex spectrum of an atmosphere can be approximated by the slope of its Rayleigh scattering, which gives our sky its blue hue as sunlight passes through it. This scattering becomes more intense as you move to higher (bluer) wavelengths. If an alien civilization were to view our Earth transiting the sun through a variety of wavelengths, our planet would appear largest as these wavelengths approached the shortest end of the visible spectrum, which would increase the depth of the transit. This same principle can be applied to other exoplanets to characterize their atmospheric chemistry. Once these techniques are further refined, we could characterize biosignatures in the atmospheres of potentially habitable planets with JWST, TMT, and E-ELT, which would allow us to obtain nearly empirical evidence of the existence of life on a planet outside of our Solar System.
Although Rayleigh scattering exists as a convenient tool for estimation of mean molecular mass (atmospheric chemistry), a certain degree of resolution is required to resolve the effect. I am currently constructing a Python model that will, when complete, allow us to determine the size of ground-based telescope required to resolve the Rayleigh scattering effect in different planetary systems. Professor Redfield and I have used the 3.5 meter WIYN telescope at Kitt Peak in an effort to make such a detection. This data is being analyzed by Coady Johnson, another member of our fantastic research team.
Professor Redfield's site: http://sredfield.web.wesleyan.edu/
In recent years, astronomers have learned how to characterize the chemistry of exoplanet atmospheres. The complex spectrum of an atmosphere can be approximated by the slope of its Rayleigh scattering, which gives our sky its blue hue as sunlight passes through it. This scattering becomes more intense as you move to higher (bluer) wavelengths. If an alien civilization were to view our Earth transiting the sun through a variety of wavelengths, our planet would appear largest as these wavelengths approached the shortest end of the visible spectrum, which would increase the depth of the transit. This same principle can be applied to other exoplanets to characterize their atmospheric chemistry. Once these techniques are further refined, we could characterize biosignatures in the atmospheres of potentially habitable planets with JWST, TMT, and E-ELT, which would allow us to obtain nearly empirical evidence of the existence of life on a planet outside of our Solar System.
Although Rayleigh scattering exists as a convenient tool for estimation of mean molecular mass (atmospheric chemistry), a certain degree of resolution is required to resolve the effect. I am currently constructing a Python model that will, when complete, allow us to determine the size of ground-based telescope required to resolve the Rayleigh scattering effect in different planetary systems. Professor Redfield and I have used the 3.5 meter WIYN telescope at Kitt Peak in an effort to make such a detection. This data is being analyzed by Coady Johnson, another member of our fantastic research team.
Professor Redfield's site: http://sredfield.web.wesleyan.edu/
James Greenwood Group (January 2014 - Present) - Detection of Lunar Apatite Hydration, Chondrule Formation
Detection of Lunar Apatite Hydration
Nominally anhydrous extraterrestrial materials may not be as dry as previously thought. We are particularly interested in studying the lunar rock returned from the Apollo missions. Using the ion microprobe at Hokkaido University, Dr. Greenwood has detected traces of hydration in the mineral apatite contained in these samples. Now, using the Hydrogen Isotope Mass Spectrometer recently obtained by our lab, we can make even more sensitive measurements of hydration right here in Connecticut. I spent summer 2014 synthesizing two different types of lunar glass with different concentrations of F/Cl, which were used as standards in the measurements of apatite hydration made by Dr. Greenwood and my undergraduate colleague, Jack Singer, using the Hokkaido University ion microprobe. The results of this effort are the basis of Jack’s senior thesis.
Chondrule Formation
A new theory to explain the formation process of chondrules has been developed in a collaborative effort between Professor James Greenwood and Professor William Herbst. I am currently working with Dr. Greenwood to design and execute the experiments necessary to prove or disprove this theory. If we are able to form the chondrule textures through this specific process of heating and cooling, the conditions of our Sun’s protoplanetary disk will be better understood.
Nominally anhydrous extraterrestrial materials may not be as dry as previously thought. We are particularly interested in studying the lunar rock returned from the Apollo missions. Using the ion microprobe at Hokkaido University, Dr. Greenwood has detected traces of hydration in the mineral apatite contained in these samples. Now, using the Hydrogen Isotope Mass Spectrometer recently obtained by our lab, we can make even more sensitive measurements of hydration right here in Connecticut. I spent summer 2014 synthesizing two different types of lunar glass with different concentrations of F/Cl, which were used as standards in the measurements of apatite hydration made by Dr. Greenwood and my undergraduate colleague, Jack Singer, using the Hokkaido University ion microprobe. The results of this effort are the basis of Jack’s senior thesis.
Chondrule Formation
A new theory to explain the formation process of chondrules has been developed in a collaborative effort between Professor James Greenwood and Professor William Herbst. I am currently working with Dr. Greenwood to design and execute the experiments necessary to prove or disprove this theory. If we are able to form the chondrule textures through this specific process of heating and cooling, the conditions of our Sun’s protoplanetary disk will be better understood.
Reinhold Blümel Group (August 2012-June 2013) - Theoretical Ion Trap Physics
The Blümel group simulates the radio-frequency heating mechanism in Paul traps using three Beowulf computer clusters. Energy provided by this radio frequency driver is converted into gaslike motion within the contained particle cloud. With the proper balance of heating (adding energy to the system) and damping (removing energy from the system), the particle clouds reach an equilibrium state. With high damping, the cloud may collapse into a crystal. While analyzing the data obtained from our numerical simulations, we found that the heating behavior of the plasmas can be described by one universal heating curve –independent of cloud size. In our paper, published in Physical Review A, we present an analytical model to explain the results of our numerical simulations: http://journals.aps.org/pra/abstract/10.1103/PhysRevA.88.041401
Professor Blümel's site: http://rblumel.faculty.wesleyan.edu/
Professor Blümel's site: http://rblumel.faculty.wesleyan.edu/