Calendar

Apr
16
Mon
Pizza Lunch: Inclusive Astronomy
Apr 16 @ 12:30 pm – 1:30 pm
Apr
23
Mon
Pizza Lunch: Moire Prescott
Apr 23 @ 12:30 pm – 1:30 pm
Pizza Lunch: Moire Prescott @ AY 119

 Glowing Cosmic Gas at Low and High Redshift

Apr
30
Mon
Pizza Lunch: Jon Holtzman
Apr 30 @ 12:30 pm – 1:30 pm
Pizza Lunch: Jon Holtzman @ AY 119

APOGEE and the Milky Way disk

May
7
Mon
Pizza Lunch: Sean Sellers and Alysha Shugart
May 7 @ 12:30 pm – 1:30 pm
Pizza Lunch: Sean Sellers and Alysha Shugart @ AY 119

ASTR 598

Jun
21
Thu
Pizza Lunch: Michael Hayden
Jun 21 @ 12:00 pm – 1:00 pm
Pizza Lunch: Michael Hayden @ AY 119

Chemical Cartography of the Milky Way

Michael Hayden, Sydney Institute for Astronomy (NMSU alumnus)

Sep
12
Wed
Colloquium PhD Thesis Defense: Alexander Thelen (Host: Nancy Chanover)
Sep 12 @ 3:00 pm – 4:00 pm
Colloquium PhD Thesis Defense: Alexander Thelen (Host: Nancy Chanover) @ Domenici Hall Room 102

The Chemical Composition and Dynamics of Titan’s Atmosphere as Revealed by ALMA

Alexander Thelen, NMSU

Over the last century, remarkable advances in our understanding of Titan’s atmosphere have been accomplished by a campaign of ground- and space-based observations revealing a wealth of complex, organic species in the moon’s upper atmosphere. Many of Titan’s atmospheric constituents produced through the photochemistry and ionospheric interactions of N2 and CH4 exhibit significant variations with latitude and time, particularly towards the poles and within the winter circumpolar vortex. The measurement of spatial and temporal variations in Titan’s atmosphere enables us to elucidate connections between its dynamics, photochemistry, and the influence of seasonal changes. At the end of the Cassini mission in 2017, we can employ the Atacama Large Millimeter/submillimeter Array (ALMA) for future observations of Titan’s atmosphere. Here we detail the analysis of numerous short integration (~3 minute) ALMA observations from 2012 to 2015 to investigate Titan’s stratospheric composition, temporal variations, and search for new molecular species. Using the Non-linear optimal Estimator for MultivariatE spectral analySIS (NEMESIS) radiative transfer code, we retrieved vertical profiles of temperature and abundance in Titan’s lower stratosphere through mesosphere (~50–550 km) from three spatially independent regions. We modeled CO emission lines to obtain temperature measurements, and retrieved abundance profiles for HCN, HC3N, C3H4, and CH3CN. The combination of integrated flux maps and vertical atmospheric profiles from spatially resolved observations allowed us to study the circulation of Titan’s middle atmosphere during northern spring. We observed increased temperatures in Titan’s stratopause at high northern latitudes and a persistent northern enrichment of HCN, C3H4, and CH3CN during this epoch; however, increased abundances of all molecules in the southern mesosphere, particularly HCN, and spatial maps of HC3N also show evidence for subsidence at the south pole. We validated these measurements through direct comparisons with contemporaneous Cassini data, previous ground-based observations, and photochemical model results. While no new trace species were detected, ALMA has proven to be a highly capable asset to enhance the data from the final few years of the Cassini mission, and for the continued study of Titan’s atmospheric dynamics, composition, and chemistry into Titan’s northern summer.

Sep
24
Mon
Pizza lunch: Drew Chojnowski
Sep 24 @ 12:30 pm – 1:30 pm
Pizza lunch: Drew Chojnowski @ AY 119

Ap Stars

Oct
8
Mon
Pizza lunch: Patrick Gaulme
Oct 8 @ 12:30 pm – 1:30 pm
Pizza lunch: Patrick Gaulme @ AY 119

Red giants, eclipsing binaries, and asteroseismology.

Patrick Gaulme, Max Planck Institute for Solar System Research

Nov
5
Mon
Pizza lunch: Heidi Sanchez
Nov 5 @ 12:30 pm – 1:30 pm
Pizza lunch: Heidi Sanchez @ AY 119

The Sunspot Solar Observatory Visitor Center

Heidi Sanchez, Sunspot Solar Observatory, NMSU

Nov
12
Mon
Pizza lunch: Nur Berdalieva and Shukur Kholikov
Nov 12 @ 12:30 pm – 1:30 pm
Pizza lunch: Nur Berdalieva and Shukur Kholikov @ AY 119

Past and Present Astronomy in Uzbekistan

Nur Berdalieva (Astronomical Institute of Uzbekistan) and Shukur Kholikov (National Solar Observatory)