Past Events in 2019

Title: Red Supergiants: New Perspectives on Dying Stars

Date: 
Wednesday, October 09, 2019 - 3:30pm PDT
Speaker: 
Emily Levesque
Affiliation: 
University of Washington
Location: 
N232 R103
Event Type: 
Colloquium

Red supergiants (RSGs) are the helium-fusing descendants of moderately massive (10-25Mo) stars. As the coldest and largest (in physical size) members of the massive star population, these evolved stars serve as ideal "magnifying glasses" for scrutinizing our current understanding of massive stars and their role as supernova progenitors.

An upGREAT View of the Treasure Chest in Carina

Date: 
Wednesday, October 16, 2019 - 9:00am PDT
Speaker: 
Bhaswati Mookerjea
Affiliation: 
TIFR
Location: 
N/A
Event Type: 
Teletalk

I will present the results of our recent study of the G287.84-0.82 cometary globule (with the Treasure Chest cluster embedded in it) in the South Pillars region of Carina. The region is interesting because it is likely shaped by the radiation and wind from eta Car and also harbors newly formed stars which appear to have created internal an Photon Dominated Region (PDR).

Tracing chemical complexity in planetary system progenitors

Date: 
Wednesday, October 16, 2019 - 3:30pm PDT
Speaker: 
Jennifer Bergner
Affiliation: 
Harvard University
Location: 
N232 R103
Event Type: 
Colloquium

Nascent planetary compositions are set by the inventories and distributions of molecules in protoplanetary disks. Understanding how planets are seeded with organic molecules, the building blocks for prebiotic chemistry, is key to assessing the habitability of other worlds. I will discuss recent progress in characterizing simple and complex organic molecules in protoplanetary disks using ALMA, and implications for the chemistry of different volatile elements (C, N, and O) in disks.

The Origins Space Telescope

Date: 
Wednesday, October 23, 2019 - 3:30pm PDT
Speaker: 
Margaret Meixner
Affiliation: 
STSCI
Location: 
N201
Event Type: 
Colloquium

Half of the light emitted by stars, planets, and galaxies over the lifetime of the Universe emerges in the infrared. The Origins Space Telescope (Origins) will access this information-rich spectral region to uncover the crucial missing pieces of our cosmic history. Origins is a community-led, NASA-supported mission concept study in preparation for the 2020 Astronomy and Astrophysics Decadal Survey.

Observing and modeling interstellar dust

Date: 
Wednesday, October 30, 2019 - 3:30pm PDT
Speaker: 
Randall Smith
Affiliation: 
CfA- Harvard
Location: 
N232 R103
Event Type: 
Colloquium

Interstellar (IS) dust grains are an integral part of IS evolution in galaxies, and our knowledge of their properties has primarily derived from observations of the UV/optical extinction, infrared emission, and polarization from grains. However, we can also learn about grains by studying the X-ray halos seen around absorbed X-ray sources that are created by small-angle X-ray scattering in dust grains along the line of sight. X-ray halos are strongly affected by the size distribution of the grains, and to a lesser extent their position, composition, and shape.

The Photochemical Evolution of the PAH Family in Photo-Dissociation Regions.

Date: 
Wednesday, November 06, 2019 - 3:30pm PST
Speaker: 
Els Peeters
Affiliation: 
University of Western Ontario
Location: 
N232 R103
Event Type: 
Colloquium

The mid-IR spectra of photodissociation regions (PDRs) are dominated by the well-known emission features at 3.3, 6.2, 7.7, 11.3, and 12.7 micron, generally attributed to polycyclic aromatic hydrocarbon molecules (PAHs). PAHs drive much of the physics and the chemistry in these PDRs, e.g. by heating the gas and as a catalyst in the formation of molecular hydrogen on their surfaces. Thus, PAHs and PDRs are intimately connected, and a complete knowledge of PDRs requires a good understanding of the properties of the PAH population.

The Cauldron of Planet Formation: Understanding our Origins with Infrared Spectroscopy

Date: 
Wednesday, November 13, 2019 - 3:30pm PST
Speaker: 
Klaus Pontoppidan
Affiliation: 
STScI
Location: 
N232 R103
Event Type: 
Colloquium

The origins of the elemental carbon, nitrogen, oxygen and hydrogen that form life can be traced back to a massive reservoir of prestellar ices, which accretes onto planet-forming disks before they take part in the formation of planetesimals and ultimately planetary atmospheres. Their chemical evolution determines the compositions of planets, including those destined to orbit in a habitable zone.

FIFI-LS Result: [CII] Line Excess in an AGN Host Galaxy

Date: 
Wednesday, November 20, 2019 - 9:00am PST
Speaker: 
Irina Smirnova-Pinchukova
Affiliation: 
MPIfA
Location: 
N/A
Event Type: 
Teletalk

I present FIFI-LS observations of 5 AGN host galaxies in [CII] line as part of the Close AGN Reference Survey (CARS, www.cars-survey.org). The [CII] 158-micron emission line is one of the strongest far-infrared lines and an important coolant in the interstellar medium of galaxies that is accessible out to high redshifts. The excitation of [CII] is complex and can best be studied in detail at low redshifts.

A Chemical and Physical Approach to Disk Evolution and Planet Formation

Date: 
Wednesday, November 20, 2019 - 3:30pm PST
Speaker: 
Dary Ruiz Rodriguez
Affiliation: 
NRAO
Location: 
N232 R103
Event Type: 
Colloquium

Winds and outflows are fundamental ingredients of star and planet formation. The energetics of outflows from young stellar objects (YSOs) are intimately connected to YSO accretion and ultimately set the initial conditions for protoplanetary disk evolution. The physical and chemical structure of the disk itself may be sharply and drastically altered by outburst events associated with episodic YSO accretion.

HIRMES Capability and Status

Date: 
Wednesday, December 04, 2019 - 9:00am PST
Speaker: 
Matt Greenhouse
Affiliation: 
NASA GSFC
Location: 
N/A
Event Type: 
Teletalk

The High Resolution Mid-Infrared Spectrometer (HIRMES) is a SOFIA facility instrument that is designed for use by the general astronomical community in support of a wide-range of exoplanet, planetary science, and astrophysics investigations. It is on track for delivery to Armstrong Flight Research Center  during December 2020 to begin flight acceptance testing. HIRMES offers slit spectroscopy with background-limited sensitivity over the 25-122 micron spectrum at 105 < R < 600, and imaging spectroscopy at R ~ 2000 over a 100x100 arc-sec FOV.

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