Calendar

Nov
6
Fri
Colloquium: John Wisniewski
Nov 6 @ 3:15 pm – 4:15 pm
Colloquium:  John Wisniewski @ BX102

Diagnosing the SEEDS of Planet Formation

John Wisniewski, University of Oklahoma

Circumstellar disks provide a useful astrophysical diagnostic of the formation and early evolution of exoplanets. It is commonly believed that young protoplanetary disks serve as the birthplace of planets, while older debris disks can provide insight into the architecture of exoplanetary systems. In this talk, I will discuss how one can use high contrast imaging techniques to spatially resolve nearby circumstellar disk systems, and how this imagery can be used to search for evidence of recently formed planetary bodies. I will focus on results from the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) project, as well as some ongoing follow-up work.

Jan
22
Fri
Colloquium: Rich Zurek (Host: Jim Murphy)
Jan 22 @ 3:15 pm – 4:15 pm
Colloquium:  Rich Zurek        (Host: Jim Murphy) @ BX102

Evolving Perspectives on the Atmosphere and Climate of Mars

            Dr. Richard Zurek, JPL

            Abstract: The planet Mars has both fascinated and tantalized humankind since the invention of the telescope and now well into the age of exploration from space. The first of three waves of space missions to Mars were flyby spacecraft that returned images of a heavily cratered planet with a thin atmosphere, suggesting Mars was more like the Moon than an older Earth. However, Mariner 9, the first spacecraft to orbit another planet, found vast channel and valley networks carved into its surface, as well as towering volcanoes, suggesting that ancient Mars was once much more Earth-like. Subsequent missions have landed on the planet and new orbiters have probed the planet at ever increasing spatial resolution and spectral coverage. As a result of the latest round of space exploration, Mars is revealed to be a complex, diverse planet— one whose climate has changed dramatically over time from an ancient atmosphere where water was active on its surface to a drier, thinner atmosphere shaped by periodic ice ages, to the present atmosphere where dynamic change continues today.

Dr. Zurek is the Chief Scientist in the Mars Program Office, Project Scientist, MRO.

Feb
12
Fri
Colloquium: Lauren Woolsey
Feb 12 @ 3:15 pm – 4:15 pm
Colloquium:  Lauren Woolsey @ BX102

Magnetic Influences on Coronal Heating and the Solar Wind

Lauren Woolsey, Harvard University

 

Abstract

The physical mechanism(s) that generate and accelerate the solar wind have not been conclusively determined after decades of study, though not for lack of possibilities. The long list of proposed processes can be grouped into two main paradigms: 1) models that require the rearranging of magnetic topology through magnetic reconnection in order to release energy and accelerate the wind and 2) models that require the launching of magnetoacoustic and Alfvén waves to propagate along the magnetic field and generate turbulence to heat the corona and accelerate the emanating wind. After a short overview of these paradigms, I will present my ongoing dissertation work that seeks to investigate the latter category of theoretical models and the role that different magnetic field profiles play in the resulting solar wind properties with Alfvén-wave-driven turbulent heating. I will describe the computer modeling in 1D and 3D that I have done of bundles of magnetic field (flux tubes) that are open to the heliosphere, and what our results can tell us about the influences of magnetic field on the solar wind in these flux tubes, including the latest time-dependent modeling that produces bursty, nanoflare-like heating. Additionally, I will present the latest results of our study of chromospheric network jets and the magnetic thresholds we are finding in magnetogram data.

Jan
24
Wed
Colloquium Thesis Proposal: Laurel Farris
Jan 24 @ 2:30 pm – 3:30 pm
Colloquium Thesis Proposal: Laurel Farris @ Science Hall, Room 110

Characterizing the oscillatory response of the chromosphere during solar flares

Laurel Farris; NMSU Astronomy Department

Quasi-periodic pulsations (QPPs) are observed in the emission of solar flares over a wide range of wavelengths,

particularly in the radio and hard x-ray regimes where non-thermal emission dominates. These pulsations are

considered to be an intrinsic feature of flares, yet the exact mechanism that triggers them remains unclear.

There have been reports of an increase in the oscillatory power at 3-minute periods (the local acoustic

cutoff frequency) in the solar chromosphere associated with flaring events. I propose to investigate the

chromospheric response to flares by inspecting the spatial and temporal onset and evolution of the 3-minute

oscillatory power, along with any QPP patterns that may appear in chromospheric emission. The analysis

will be extended to multiple flares, and will include time before, during, and after the main event. To test

initial methods, the target of interest was the well-studied 2011 February 15 X-class flare. Data from two

instruments on board the Solar Dynamics Observatory (SDO) were used in the preliminary study, including

continuum images from the Helioseismic and Magnetic Imager (HMI) and UV images at 1600 and 1700

Angstroms from the Atmospheric Imaging Assembly (AIA). Later, spectroscopic data from the Interface

Region Imaging Spectrometer (IRIS) will be used to examine velocity patterns in addition to intensity.

Jan
26
Fri
Colloquium: Zheng Cai (Host: Kristian Finlator)
Jan 26 @ 3:15 pm – 4:15 pm
Colloquium: Zheng Cai (Host: Kristian Finlator) @ BX102

Colloquium Title

Colloquium Speaker Name, Affiliation

Abstract text

Feb
5
Mon
PDS Atmospheres Node meeting
Feb 5 @ 3:00 pm – 4:00 pm