Calendar

Aug
28
Fri
Colloquium Thesis Proposal: Laura Mayorga
Aug 28 @ 3:15 pm – 4:15 pm
Colloquium Thesis Proposal: Laura Mayorga @ BX102

Probing Exoplanet Atmospheric Properties from Phase Variations and Polarization

Laura Mayorga, NMSU

The study of exoplanets is evolving past simple transit and Doppler method discovery and characterization. One of the many goals of the upcoming mission WFIRST-AFTA is to directly image giant exoplanets with a coronagraph. We undertake a study to determine the types of exoplanets that missions such as WFIRST will encounter and what instruments these missions require to best characterize giant planet atmospheres. We will first complete a benchmark study of how Jupiter reflects and scatters light as a function of phase angle. We will use Cassini flyby data from late 2000 to measure Jupiter’s phase curve, spherical albedo, and degree of polarization. Using Jupiter as a comparison, we will then study a sample of exoplanet atmosphere models generated to explore the atmospheric parameter space of giant planets and estimate what WFIRST might observe. Our study will provide valuable refinements to Jupiter-like models of planet evolution and atmospheric composition. We will also help inform future missions of what instruments are needed to characterize similar planets and what science goals will further our knowledge of giant worlds in our universe.

Oct
30
Fri
Colloquium: Sergio Rodriguez
Oct 30 @ 3:15 pm – 4:15 pm
Colloquium: Sergio Rodriguez @ BX102

BOSS DR12 survey: Clustering of galaxies and Dark Matter Haloes

Sergio Rodriguez, UAM, Madrid and Cal. Berkeley

BOSS SDSS-III is the largest redshift survey for the large scale structure and a powerful sample for the study of the low redshift Baryonic Acoustic Oscillations. We combine the features of the survey, such as, geometry, angular incompleteness and stellar mass incompleteness, with the BigMultiDark cosmological simulation to do a study of the distribution of galaxies in the dark matter halos. Using this large N-Body simulation and the halo abundance matching technique, we found a remarkably good agreement with the 2-point and 3-point statistics of the data.

Mar
4
Fri
Colloquium: Gail Zasowski (Host: Drew Chojnowski)
Mar 4 @ 3:15 pm – 4:15 pm
Colloquium:  Gail Zasowski  (Host: Drew Chojnowski) @ BX102

New Tools for Galactic Archaeology from the Milky Way

Gail Zasowski, John Hopkins University

One of the critical components for understanding galaxy evolution is understanding the Milky Way Galaxy itself — its detailed structure and chemodynamical properties, as well as fundamental stellar physics, which we can only study in great detail locally.  This field is currently undergoing a dramatic expansion towards the kinds of large-scale statistical analyses long used by the extragalactic and other communities, thanks in part to an enormous influx of data from space- and ground-based surveys.  I will describe the Milky Way and Local Group in the context of general galaxy evolution and highlight some recent developments in Galactic astrophysics that take advantage of these big data sets and analysis techniques.  In particular, I will focus on two diverse approaches: one to characterize the distribution and dynamics of the carbon-rich, dusty diffuse ISM, and one to map the resolved bulk stellar properties of the inner disk and bulge.  The rapid progress in these areas promises to continue, with the arrival of data sets from missions like SDSS, Gaia, LSST, and WFIRST.

May
31
Tue
Colloquium PhD Defense: Diane Feuillet
May 31 @ 3:00 pm – 4:00 pm
Colloquium PhD Defense: Diane Feuillet @ Dominici106

Ages and Abundance of Local Stellar Populations

Diane Feuillet, NMSU

Sep
20
Tue
Colloquium Thesis Proposal: Ethan Dederick
Sep 20 @ 3:00 pm – 4:00 pm
Colloquium Thesis Proposal: Ethan Dederick @ Science Hall 310

Utilizing Planetary Oscillations to Constrain the Interior Structure of the Jovian Planets

Ethan Dederick

Seismology has been the premier tool of study for understanding the
interior structure of the Earth, the Sun, and even other stars. Yet in this
thesis proposal, we wish to utilize these tools to understand the interior
structure of the Jovian planets, Saturn in particular. Recent observations
of spiral density structures in Saturn’s rings caused by its oscillations
have provided insight into which modes exist within Saturn and at what
frequencies. Utilizing these frequencies to compare to probable mode can-
didates calculated from Saturn models will also us to ascertain the interior
profiles of state variables such as density, sound speed, rotation, etc. Using
these profiles in a Saturn model, coupled with tweaking the interior struc-
ture of the model, i.e. the inclusion of stably stratified regions, should
allow us to explain which modes are responsible for the density structures
in the rings, as well as predict where to look to find more such structures.
In doing so, we will not only have a much greater understanding of Sat-
urn’s interior structure, but will have constructed a method that can also
be applied to Jupiter once observations of its mode frequencies become
available. In addition, we seek to explain if moist convection on Jupiter is
responsible for exciting its modes. We aim to do this by modeling Jupiter
as a 2D harmonic oscillator. By creating a resonance between moist con-
vective storms and Jovian modes, we hope to match the expected mode
energies and surface displacements of Jupiter’s oscillations.

Mar
6
Mon
Pizza Lunch: F.X. Schmider
Mar 6 @ 12:30 pm – 1:30 pm
Pizza Lunch: F.X. Schmider

JIVE/JOVIAL, a network for Jupiter’s seismology and atmosphere dynamics

F.X. Schmider, Observatoire de la Cote d’Azur

Mar
28
Tue
Joint Physics/Astronomy Colloquium: William Newman
Mar 28 @ 4:00 pm – 5:00 pm
Joint Physics/Astronomy Colloquium: William Newman @ Gardiner Hall 229, Physics. Dept. | Ames | Iowa | United States

Giant Planet Shielding of the Inner Solar System Revisited: Blending Celestial Mechanics with Advanced Computation

Dr. William Newman, UCLA

The Earth has sustained during the last billion years as many as five catastrophic collisions with asteroids and comets which led to widespread species extinctions. Our own atmosphere was literally blown away 4.5 billion years ago by a collision with a Mars-sized impactor. However, collisions with comets originating in the outer solar system accreted much of the present-day atmosphere. Relatively advanced life on our planet is the beneficiary of a number of impact events during Earth’s history which built our atmosphere without destroying a large fraction of terrestrial life. Using very high precision Monte Carlo integration methods to explore the orbital evolution over hundreds of millions of years followed by the application of celestial mechanical techniques, the presentation will explain directly how Earth was shielded by the combined influence of Jupiter and Saturn, assuring that only 1 in 100,000 potential collisions with the Earth will materialize.

 

Nov
9
Thu
Public Talk: “Preparing to Explore the Universe with the James Webb Space Telescope” – Dr. Jane Rigby (NASA Goddard)
Nov 9 @ 7:00 pm – 8:00 pm
Public Talk: "Preparing to Explore the Universe with the James Webb Space Telescope" - Dr. Jane Rigby (NASA Goddard) @ Gerald Thomas Hall, Room 194

Preparing to Explore the Universe with the James Webb Space Telescope

Dr. Jane Rigby (NASA Goddard, Deputy Project Scientist for JWST)

Abstract: NASA’s James Webb Space Telescope (JWST), scheduled to be launched in 2019, will revolutionize our view of the Universe.  As the scientific successor to the Hubble Space Telescope, JWST will rewrite the textbooks and return gorgeous images and spectra of our universe.   In my talk, I will show how JWST will revolutionize our understanding of how galaxies and supermassive black holes formed in the first billion years after the Big Bang, and how they evolved over cosmic time.  I’ll describe how our international team is preparing for launch, how we decide what targets to observe, and how we are testing the telescope to be sure it will work in space.

More information about the telescope can be found at https://www.jwst.nasa.gov/.

 

 

Dec
4
Mon
Pizza Lunch: Karen Kinemuchi
Dec 4 @ 12:30 pm – 1:30 pm
Pizza Lunch: Karen Kinemuchi @ AY 119

Life at Apache Point Observatory

Mar
28
Wed
Colloquium PhD Thesis Defense: Ethan Dederick
Mar 28 @ 3:15 pm – 4:15 pm
Colloquium PhD Thesis Defense: Ethan Dederick @ Science Hall 109

Seismic Inferences of Gas Giant Planets: Excitation & Interiors

Ethan Dederick, NMSU

Seismology has been the premier tool of study for understanding the interior structure of the Earth, the Sun, and even other stars. In this thesis we develop the framework for the first ever seismic inversion of a rapidly rotating gas giant planet. We extensively test this framework to ensure that the inversions are robust and operate within a linear regime. This framework is then applied to Saturn to solve for its interior density and sound speed profiles to better constrain its interior structure. This is done by incorporating observations of its mode frequencies derived from Linblad and Vertical Resonances in Saturn’s C-ring. We find that although the accuracy of the inversions is mitigated by the limited number of observed modes, we find that Saturn’s core density must be at least 8.97 +/- 0.01 g cm^{-3} below r/R_S = 0.3352 and its sound speed must be greater than 54.09 +/- 0.01 km s^{-1} below r/R_S = 0.2237. These new constraints can aid the development of accurate equations of state and thus help determine the composition in Saturn’s core. In addition, we investigate mode excitation and whether the \kappa-Mechanism can excite modes on Jupiter. While we find that the \kappa-Mechanism does not play a role in Jovian mode excitation, we discover a different opacity driven mechanism, The Radiative Suppression Mechanism, that can excite modes in hot giant planets orbiting extremely close to their host stars if they receive a stellar flux greater than 10^9~erg cm^{-2} s^{-1}. Finally, we investigate whether moist convection is responsible for exciting Jovian modes. Mode driving can occur if, on average, one cloud column with a 1-km radius exists per 6423 km^2 or if ~43 storms with 200 columns, each with a radius of 25 km, erupt per day. While this seems unlikely given current observations, moist convection does have enough thermal energy to drive Jovian oscillations, should it be available to them.