Calendar

Jun
27
Tue
Colloquium PhD Defense: Laura Mayorga
Jun 27 @ 2:30 pm – 3:30 pm
Colloquium PhD Defense: Laura Mayorga @ Domenici Hall 102

The Orbital and Planetary Phase Variations of Jupiter-Sized Planets: Characterizing Present and Future Giants

Laura Mayorga, NMSU

It is commonly said that exoplanet science is 100 years behind planetary science. While we may be able to travel to an exoplanet in the future, inferring the properties of exoplanets currently relies on extracting as much information as possible from a limited dataset. In order to further our ability to characterize, classify, and understand exoplanets as both a population and as individuals, this thesis makes use of multiple types of observations and simulations.

Firstly, direct-imaging is a technique long used in planetary science and is only now becoming feasible for exoplanet characterization. We present our results from analyzing Jupiter’s phase curve with Cassini/ISS to instruct the community in the complexity of exoplanet atmospheres and the need for further model development. The planet yields from future missions may be overestimated by today’s models. We also discuss the need for optimal bandpasses to best differentiate between planet classes.

Secondly, photometric surveys are still the best way of conducting population surveys of exoplanets. In particular, the Kepler dataset remains one of the highest precision photometric datasets and many planetary candidates remain to be characterized. We present techniques by which more information, such as a planet’s mass, can be extracted from a transit light curve without expensive ground- or space-based follow-up observations.

Finally, radial-velocity observations have revealed that many of the larger “planets” may actually be brown dwarfs. To understand the distinction between a brown dwarf and an exoplanet or a star, we have developed a simple, semi-analytic viscous disk model to study brown dwarf evolutionary history. We present the rudimentary framework and discuss its performance compared to more detailed numerical simulations as well as how additional physics and development can determine the potential observational characteristics that will differentiate between various formation scenarios.

Exoplanet science has already uncovered a plethora of previously unconsidered phenomenon. To increase our understanding of our own planet, as well as the other various possible end cases, will require a closer inspection of our own solar system, the nuanced details of exoplanet data, refined simulations, and laboratory astrophysics.

Mar
29
Thu
Colloquium (Joint with Physics): Jim Fuller (Host: Ethan Dederick)
Mar 29 @ 4:00 pm – 5:00 pm
Colloquium (Joint with Physics): Jim Fuller (Host: Ethan Dederick) @ Gardiner Hall 230

Surprising Impacts of Gravity Waves

Jim Fuller, Caltech

Gravity waves are low frequency fluid oscillations restored by buoyancy forces in planetary and stellar interiors. Despite their ubiquity, the importance of gravity waves in evolutionary processes and asteroseismology has only recently been appreciated. For instance, Kepler asteroseismic data has revealed gravity modes in thousands of red giant stars, providing unprecedented measurements of core structure and rotation. I will show how gravity modes (or lack thereof) can also reveal strong magnetic fields in the cores of red giants, and I will demonstrate that strong fields appear to be common within “retired” A stars but are absent in their lower-mass counterparts. In the late phase evolution of massive stars approaching core-collapse, vigorous convection excites gravity waves that can redistribute huge amounts of energy within the star. I will present preliminary models of this process, showing how wave energy redistribution can drive outbursts and enhanced mass loss in the final years of massive star evolution, with important consequences for the appearance of subsequent supernovae.
Jan
7
Mon
PDS Atmospheres Node meeting
Jan 7 @ 3:30 pm – 4:30 pm
PDS Atmospheres Node meeting @ AY 119

Detailed Node Meeting Schedule:

1/07: ELSA & Node
1/14: ELSA
1/21: nothing – MLK holiday
1/28: Node
2/04: ELSA
2/11: Node
2/18: ELSA
2/25: Node
3/04: ELSA
3/11: Node
3/18: ELSA (but Lynn not here, LPSC)
3/25: nothing – Spring Break
4/01: Node
4/08: ELSA
4/15: Node
4/22: ELSA
4/29: Node
5/06: nothing – Final Exams week
5/13: ELSA

Jan
14
Mon
PDS Atmospheres Node meeting
Jan 14 @ 3:30 pm – 4:30 pm
PDS Atmospheres Node meeting @ AY 119

Detailed Node Meeting Schedule:

1/07: ELSA & Node
1/14: ELSA
1/21: nothing – MLK holiday
1/28: Node
2/04: ELSA
2/11: Node
2/18: ELSA
2/25: Node
3/04: ELSA
3/11: Node
3/18: ELSA (but Lynn not here, LPSC)
3/25: nothing – Spring Break
4/01: Node
4/08: ELSA
4/15: Node
4/22: ELSA
4/29: Node
5/06: nothing – Final Exams week
5/13: ELSA

Jan
21
Mon
PDS Atmospheres Node meeting
Jan 21 @ 3:30 pm – 4:30 pm
PDS Atmospheres Node meeting @ AY 119

Detailed Node Meeting Schedule:

1/07: ELSA & Node
1/14: ELSA
1/21: nothing – MLK holiday
1/28: Node
2/04: ELSA
2/11: Node
2/18: ELSA
2/25: Node
3/04: ELSA
3/11: Node
3/18: ELSA (but Lynn not here, LPSC)
3/25: nothing – Spring Break
4/01: Node
4/08: ELSA
4/15: Node
4/22: ELSA
4/29: Node
5/06: nothing – Final Exams week
5/13: ELSA

Jan
23
Wed
Colloquium Thesis Defense: Lauren Kahre
Jan 23 @ 3:00 pm – 4:00 pm
Colloquium Thesis Defense: Lauren Kahre

Extinction Mapping and Dust-to-Gas Ratios of Nearby Galaxies

Lauren Kahre, NMSU

We present a study of the dust{to{gas ratios in 31 nearby (D >
10 Mpc) galaxies. Using Hubble Space Telescope broad band WFC3/UVIS UV and
optical images from the Treasury program LEGUS (Legacy ExtraGalactic UV
Survey) combined with archival HST/ACS data, we correct thousands of
individual stars for extinction across these galaxies using an
isochrone-matching (reddening-free Q) method. We generate extinction maps
for each galaxy from the individual stellar extinctions using both
adaptive and fixed resolution techniques, and correlate these maps with
neutral HI and CO gas maps from literature, including The HI Nearby Galaxy
Survey (THINGS) and the HERA CO-Line ExtraGalactic Survey (HERACLES). We
calculate dust-to-gas ratios and investigate variations in the dust-to-gas
ratio with galaxy metallicity. We find a power law relationship between
dust-to-gas ratio and metallicity. The single power law is consistent with
other studies of dust-to-gas ratio compared to metallicity, while the
broken power law shows a significantly shallower slope for low metallicity
galaxies than previously observed. We find a change in the relation when
H_2 is not included. This implies that underestimation of N_H2 in
low-metallicity dwarfs from a too-low CO-to-H2 conversion factor X_CO
could have produced too low a slope in the derived relationship between
dust-to-gas ratio and metallicity. We also
compare our extinctions to those derived from fitting the spectral energy
distribution (SED) using the Bayesian Extinction and Stellar Tool (BEAST)
for NGC 7793 and and systematically lower extinctions from SED-fitting as
compared to isochrone matching. Finally, we compare our extinction maps of
NGC 628 to maps of the dust obtained via IR emission from Aniano et al.
(2012) and find a factor of 2 difference in dust-to-gas ratios determined
from the two maps, consistent with previous work.

Jan
25
Fri
Pizza Lunch Talk: Dale Frail
Jan 25 @ 11:30 am – 12:30 pm
Pizza Lunch Talk: Dale Frail @ AY 119

How to Write A Competitive Prize Postdoc Application

Dale Frail, NRAO

Colloquium: Dale Frail (Host: Sarah Kovac)
Jan 25 @ 3:15 pm – 4:15 pm
Colloquium: Dale Frail (Host: Sarah Kovac) @ BX102

Multi-Messenger EM-GW Astronomy: The View from the Radio End of the EM Spectrum

Dale Frail, NRAO

Abstract: With the discovery of gravitational waves and electromagnetic radiation from the binary neutron star merger GW170817, the era of GW multi-messenger astronomy has begun with style. I will describe the discovery, show where progress has been made in several areas, and then move on to describe a controversy regarding the origin of the afterglow emission. After explaining the importance of this issue, I will show how late-time radio observations have decisively resolved the issue. I will end with a discussion of the future, with an emphasis on the role of radio observations in finding and studying EM counterparts.

Jan
28
Mon
PDS Atmospheres Node meeting
Jan 28 @ 3:30 pm – 4:30 pm
PDS Atmospheres Node meeting @ AY 119

Detailed Node Meeting Schedule:

1/07: ELSA & Node
1/14: ELSA
1/21: nothing – MLK holiday
1/28: Node
2/04: ELSA
2/11: Node
2/18: ELSA
2/25: Node
3/04: ELSA
3/11: Node
3/18: ELSA (but Lynn not here, LPSC)
3/25: nothing – Spring Break
4/01: Node
4/08: ELSA
4/15: Node
4/22: ELSA
4/29: Node
5/06: nothing – Final Exams week
5/13: ELSA

Feb
4
Mon
PDS Atmospheres Node meeting
Feb 4 @ 3:30 pm – 4:30 pm
PDS Atmospheres Node meeting @ AY 119

Detailed Node Meeting Schedule:

1/07: ELSA & Node
1/14: ELSA
1/21: nothing – MLK holiday
1/28: Node
2/04: ELSA
2/11: Node
2/18: ELSA
2/25: Node
3/04: ELSA
3/11: Node
3/18: ELSA (but Lynn not here, LPSC)
3/25: nothing – Spring Break
4/01: Node
4/08: ELSA
4/15: Node
4/22: ELSA
4/29: Node
5/06: nothing – Final Exams week
5/13: ELSA