Spotlight
Meet 'El Gato,' the UA's New Supercomputer
University of Arizona assistant professor of astronomy Brant Robertson is propelling the UA’s computational facilities to the forefront of contemporary computer technology. Robertson and collaborators obtained a $1.3 million grant from the National Science Foundation to help fund the implementation of a new generation of supercomputers on campus. Read More
Congratulations to our Senior Bachelor of Science Students
On Thursday, April 24, the Dept. of Astronomy honored the seven matriculating senior undergrads at a brief pre-colloquium ceremony. The photo shows Director Buell Jannuzi with, from left to right, Kyle Pearson, Cassandra Lejoly, Spencer Wallace, Amanda Walker-LaFollette, Ian Cates and Lauren Biddle, (Christen Jones, not pictured). Undergrad Studies Program Coordinator Yancy Shirley also announced that Amanda Walker-LaFollette is this year's recipient of the Research Excellence Award, and Cassandra Lejoly received the Astronomy Outstanding Senior award. Four of the students then gave 15-minute colloquia each to an appreciative audience of professors, postdocs, grad students, and undergrads. All of the members of the Astronomy Department wish each of the seven undergrads the best of luck in their chosen future endeavors.
RIP Russ Warner
"It saddens me to inform you that Russ Warner passed away last week. Many of you had interactions with Russ as he held several positions over the 29 years he worked at Steward Observatory. Russ was initially hired in 1984 as a Project Manager for Mt. Graham Observatory, where he worked on the original site testing for what would become Mt Graham International Observatory. In about 1986, Russ switched hats to manage the Mirror Lab. In 1992, he became Administrative Manager of the Sub-Millimeter Telescope Observatory. In 2000, he transferred as Administrative Manager to the Technical Division (now Engineering Technical Services). He was our Building Monitor, Department Export Control Administrator, and manager for many years. Russ enjoyed travelling both internationally and domestically. He is survived by his wife, Anne, and will be missed dearly by family and friends."
Graduating Astronomy Major Research Symposium
On Thursday. April 24, at 3:45pm, a regular weekly research colloquium will be held, this time featuring four of our matriculating senior undergraduates. Lauren Biddle, Spencer Wallace, Amanda Walker-LaFollette, and Cassandra Lejoly will speak. Their abstracts are below. Please do join us. Pictured are Amanda Walker-LaFollette (left), Lauren Biddle (center), and Cassandra Lejoly (right). Not pictured, Spencer Wallace.
Lauren Biddle
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It is important to explore the diversity of characteristics of ice giants to understand the nature and evolution of this class of planets. We present a homogeneous analysis of 12 new and 9 previously published broadband photometric observations of the Uranus-sized extrasolar planet GJ 3470b, which belongs to the growing sample of sub-Jovian bodies orbiting M dwarfs. The consistency of our analysis explains some of the discrepancies between previously published results and provides updated constraints on the planetary parameters. Our data are also consistent with previous transit observations of this system. The physical properties of the transiting system can only be constrained as well as the host star is characterized, so we provide new spectroscopic measurements of GJ 3470 from 0.33 to 2.42 μm to aid our analysis. We also perform a second analysis of the transmission spectrum of the entire ensemble of transit observations to date, supporting the existence of a H2 dominated atmosphere exhibiting a strong Rayleigh scattering slope.
Spencer Wallace
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Current mixing length theories fail to properly address the interactions that occur between convective and stably stratified regions in stars. Purely local, static criteria such as Schwarzchild and Ledoux do not account for the mixing that occurs at the convective boundaries. We propose a dynamic boundary condition, based on the properties of the turbulent convective flow near the boundary, and describe how we implemented such a mixing mechanism in the MESA stellar evolution code. We also briefly consider how turbulence near the convective boundary affects semiconvective mixing.
Amanda Walker-LaFollette
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We conducted a survey of the 63 starless and prestellar cores in the Perseus molecular cloud to study the kinematics of the cores using the Arizona Radio Observatory 12m telescope. We observed the cores in HCN and H13CN and looked for blue asymmetry in the line profile, a sign of infall. We classified the line profiles based on whether there is a clear asymmetry or skew in the profile. Blue asymmetric infall profiles across an entire starless and prestellar core population are rare. Comparing to the number of class II protostars in Perseus we estimated the lifetime of collapsing prestellar cores to be (0.25 - 1.6)×105yrs, which is 0.74 - 4.7 times longer than the gravitational freefall time. This could indicate that some of the infall candidates are tracing larger scale flows.
Cassandra Lejoly
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I will present the periods of repeatability of individual coma features in Comet 1P/Halley measured using the position angle at different spatial distances from the nucleus in consequent cycles. I found that separate features appear to have different periods of repeatability within the same images, perhaps depending on the corresponding source regions on the nucleus. The periods of repeatability of coma morphologies will be presented as a function of time from the perihelion. I will also discuss the current work being done on the outflow velocities of the dust as well as the comprehensive modeling of the comet’s features.
2014 Outstanding Graduate Student Awardees
This year’s Department of Astronomy awards to outstanding graduate students, one in each of three categories, are the following:
Scholarship: Kathryn Decker French
Service: Kate Follette
Teaching: Megan Kiminki
Further, Kate Follette received the 2014 Outstanding Service Award for the entire College of Science, which was presented by Associate Dean Elliott Cheu to Kate in a special ceremony on Apr 16th.
Please join me in congratulating these students on their awards.
-Buell Jannuzi
LSST and OSIRIS-REx
Reporter Tom Beal fills us in on the latest from LSST and OSIRIS-REx
Two Tucson-based space science projects are moving from design to construction. OSIRIS-REx, the asteroid sampling mission being led by the University of Arizona’s Lunar and Planetary Laboratory, has been cleared by NASA to begin building a spacecraft, flight instruments, ground system and launch support facilities. The Large Synoptic Survey Telescope has passed its design review. Money for construction is in this year’s federal budget and a July date has been set for construction, pending final approval by the National Science Board in early May.
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