Calendar

Nov
9
Mon
Pizza Lunch: Karen Kinemuchi
Nov 9 @ 12:30 pm – 1:30 pm
Pizza Lunch: Karen Kinemuchi

High-precision studies of RR Lyrae Stars

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.

Jan
29
Fri
Colloquium Thesis Proposal: Kathryn Steakley (Host: Jim Murphy)
Jan 29 @ 3:00 pm – 4:00 pm
Colloquium Thesis Proposal:  Kathryn Steakley  (Host: Jim Murphy) @ BX102

Exploring Impact Heating of the Early Martian Climate

Kathryn Steakley, NMSU

ABSTRACT: Geological evidence implies that Mars may have had a more warm and wet environment during the late Noachian / early Hesperian era (3.5–3.8 billion years ago), but climate models struggle to reproduce such warm conditions. Prior studies with one-dimensional atmospheric models indicate that the water and energy from impacts could provide enough greenhouse warming to raise temperatures above the freezing point of liquid water for many years. We will use the NASA Ames Research Center Mars GCM to characterize potential atmospheric changes induced by impactors ranging in diameter from 50 m to 100 km on a range of early Mars surface pressure scenarios (10-mbar, 100-mbar, 300-mbar, 1-bar, 2-bar, 3-bar). Our objectives are 1) to examine the temperature behavior of the early Martian climate following impacts and determine if environmental conditions on its surface could support liquid water for extended periods of time, and 2) to quantify precipitation rates and examine rainfall patterns on a simulated early Martian surface following impacts and determine if this mechanism is possibly responsible for the formation of observed river valley networks on Mars. Examining climate conditions after impacts with a GCM will allow us to test a potential mechanism for heating the early Martian atmosphere, constrain the magnitude and temporal duration of these potential heating events, and provide insight regarding the availability of liquid water on early Mars which is relevant to its past habitability.

 

Feb
8
Mon
Pizza Lunch: Vincent Boening
Feb 8 @ 12:30 pm – 1:30 pm
Pizza Lunch: Vincent Boening @ AY 119

Solar Meridional Flows from Time-Distance Helioseismology

Vincent Boening, Kippenheuer Institute for Solar Physics, Freiburg, Germany

 

Apr
15
Fri
Colloquium: Warren Skidmore (Host: Jim Murphy)
Apr 15 @ 3:15 pm – 4:15 pm
Colloquium:  Warren Skidmore     (Host: Jim Murphy) @ BX102

The Thirty Meter Telescope:   The Next Generation Ground Based Optical/InfraRed Observatory

Dr. Warren Skidmore, Thirty Meter Telescope Corp.

 

Abstract: After a construction status update, I will describe how the telescope design was developed to support a broad range of observing capabilities and how the observatory is being engineered. I’ll discuss some of the observational capabilities that the Thirty Meter Telescope will provide and some of the areas of study that will benefit from the TMT’s capabilities, specifically synergistic areas with new and future proposed astronomical facilities. Finally I will describe the avenues through which astronomers can have some input in the planning of the project and potential NSF partnership, prioritizing the development of 2nd generation instruments and directing the scientific aims for the observatory.

Apr
22
Fri
Colloquium: Paul Abell (Host: Nancy Chanover)
Apr 22 @ 3:15 pm – 4:15 pm
Colloquium:  Paul Abell  (Host: Nancy Chanover) @ BX102

Asteroid Exploration

Paul Abell, NASA Johnson Flight Center

I will present the current status of NASA’s Asteroid Redirect Mission (ARM) that is planned for launch in December 2021. Specifically I will discuss how a solar-electric powered robotic spacecraft will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, perform a planetary defense technique at the NEA, and return with the boulder into a stable orbit around the Moon. I will also discuss how astronauts aboard an Orion spacecraft will subsequently explore the boulder, conduct investigations during their extravehicular activities, and return samples to Earth. I will demonstrate how the ARM is part of NASA’s plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. Finally I will discuss how the ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in terms of science, planetary defense, and in-situ resource utilization (ISRU).

May
12
Thu
Colloquium PhD Defense: Kenz Arraki
May 12 @ 3:00 pm – 4:00 pm
Colloquium PhD Defense: Kenz Arraki @ Dominici106

Evolution of Dwarf Galaxy Properties in Local Group Environments

Kenz Arraki, NMSU

Feb
27
Mon
Pizza Lunch: Jason Jackiewicz
Feb 27 @ 12:30 pm – 1:30 pm
Pizza Lunch: Jason Jackiewicz @ AY 119

The Sun’s Internal Conveyor Belt (update)

Jason Jackiewicz

 

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.

 

Sep
1
Fri
Colloquium: Isak Wold (Host: Moire Prescott)
Sep 1 @ 3:15 pm – 4:15 pm
Colloquium: Isak Wold (Host: Moire Prescott) @ BX102

A Faint Flux-Limited LAE Sample at z = 0.3

Isak Wold, UT Austin

Observational surveys of Lya emitters (LAEs) have proven to be an efficient method to identify and study large numbers of galaxies over a wide redshift range. To understand what types of galaxies are selected in LAE surveys – and how this evolves with redshift – it is important to establish a low-redshift reference sample that can be directly compared to high-redshift samples.  The lowest redshift where a direct Lya survey is currently possible is at a redshift of z~0.3 via the Galaxy Evolution Explorer (GALEX ) FUV grism data. Using the z~0.3 GALEX sample as an anchor point, it has been suggested that at low redshifts high equivalent width (EW) LAEs become less prevalent and that the amount of escaping Lya emission declines rapidly.  A number of explanations for these trends have been suggested including increasing dust content, increasing neutral column density, and/or increasing metallicity of star-forming galaxies at lower redshifts. However, the published z~0.3 GALEX sample is pre-selected from bright NUV objects.  Thus, objects with strong Lya emission but faint continuum (high-EW LAEs) could be missed.  In this talk, I will present my efforts to re-reduce the deepest archival GALEX FUV grism data and obtain a sample that is not biased against high-EW LAEs.  I will discuss the implications of this new sample on the evolutionary trends listed above.