Utah Aurora - May 10/11 2024

BYU Astronomy Research Group Joins the Astrophysical Research Consortium (ARC)

As of January 2021 BYU will be a member of the ARC Consortium (Link to Consortium) with access to the ARC 3.5-m telescope and the 0.5-m ARCSAT telescope.  The primary use of the ARC 3.5-m telescope time is for graduate student projects.  This provides a wide array of instrumentation that is currently being used to study objects in the solar system all the way to studies of the large scale structure of the Universe.

Other BYU Astronomy Facilities

In addition to our telescope time from the ARC consortium, we operate a number of our own astronomical facilities

West Mountain Observatory (West Mountain)

This is our mountain observatory at about 6600 ft above sea level.  This consists of three telescopes: 0.9-m, 0.5-m, and a 0.32-m. It is a 40 minute drive that ends in a 5 miles drive up a dirt road. The mountain itself can be seen from campus. We don't provide any tours of this facility.

Orson Pratt Observatory

The Orson Pratt Observatory is named for an early apostle of the Church of Jesus Christ of Latter-Day Saints.  It is our campus telescope facility and contains a wide variety of telescopes for student research and public outreach. We operate a 24" PlaneWave telescope in the main campus dome, plus a 16", two 12", one 8", and a 6" telescope on our observation deck.  The telescopes are all fully robotic. Beyond this we have a large sections of telescopes used on public nights.

Royden G. Derrick Planetarium (Planetarium)

This is a 119 seat, 39" dome planetarium with acoustically treated walls to allow it's use as a lecture room. Recently we upgraded to an E&S Digistar7 operating system with 4K projectors.  The planetarium is used for teaching classes, public outreach, and astronomy education research projects.





Selected Publications

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Testing Model-determined Temperatures in the Hyades: A Bayesian Approach

Gains in our understanding of stellar evolution over the last century are largely due to improvements in stellar models. One key aspect in the use of these models is a reliable transformation between theoretical values (such as luminosity and temperature) to observable quantities (such as magnitude and color). To assess the current state of this transformation, we sought to compare model-determined temperatures from color–magnitude diagram fitting to temperatures obtained from photometric colors or spectroscopy. Our sample for analysis was 88 nonbinary stars in the Hyades open star cluster. By applying a sophisticated Bayesian algorithm we fit five widely available model sets to high-quality photometric data combined with Gaia parallaxes. This analysis provides specific feedback for improving temperature–color transformations, as well as practical guidance for using results based on these models.

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Observing Globular Cluster RR Lyrae Variables with the BYU West Mountain Observatory
We have utilized the 0.9-meter telescope of the Brigham Young University West Mountain Observatory to secure data on six northern hemisphere globular clusters. Here we present representative observations of RR Lyrae stars located in these clusters, including light curves. We compare light curves produced using both DAOPHOT and ISIS software packages. Light curve fitting is done with FITLC. We find that for well-separated stars, DAOPHOT and ISIS provide comparable results. However, for stars within the cluster core, ISIS provides superior results. These improved techniques will allow us to better measure the properties of cluster variable stars.
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Deep Observations of the Open Cluster NGC 6253
We have obtained deep observations of the metal-rich open cluster NGC
6253 with GMOS on the Gemini-South telescope, with the goal of observing the cluster
white dwarfs for the first time. These observations are an important piece and further
test of the variously proposed scenarios to explain the formation of the strange white
dwarfs in the metal rich open cluster NGC 6791. We will use the new observations of
NGC 6253 to measure the cluster’s white dwarf age and search for any anomalies in the
white dwarf luminosity function. The high metallicity of this cluster will allow us to
explore and better understand the formation of white dwarfs in such a high metallicity
environment. These observations are an important piece in the continuing puzzle that
has important implications on mass loss, white dwarf cooling, and stellar evolution as
a whole.
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Deriving Precise Ages of Field White Dwarfs using Bayesian Techniques
We apply a self-consistent and robust Bayesian statistical approach along with modern model ingredients to determine the posterior age distributions for nine DC field white dwarfs. Our technique requires only quality optical and near-IR photometry to derive ages with uncertainties that range from as little as 4% to as much as 27%, depending on the star. We use these results to demonstrate the non-Gaussian nature of white dwarf age posteriors and to compare the effect on ages of two modern initial final mass relations. We additionally predict the capabilities of our Bayesian technique in the GAIA era, when we will possess distances accurate to 1-2% for thousands of white dwarfs.
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Deriving the Ages of Field White Dwarfs
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A Deep Proper Motion Catalog Within the Sloan Digital Sky Survey Footprint
A new proper motion catalog is presented, combining the Sloan Digital Sky Survey (SDSS) with second epoch observations in the r band within a portion of the SDSS imaging footprint. The new observations were obtained with the 90prime camera on the Steward Observatory Bok 90 inch telescope, and the Array Camera on the U.S. Naval Observatory, Flagstaff Station, 1.3 m telescope. The catalog covers 1098 square degrees to r = 22.0, an additional 1521 square degrees to r = 20.9, plus a further 488 square degrees of lesser quality data. Statistical errors in the proper motions range from 5 mas year-1 at the bright end to 15 mas year-1 at the faint end, for a typical epoch difference of six years. Systematic errors are estimated to be roughly 1 mas year-1 for the Array Camera data, and as much as 2-4 mas year-1 for the 90prime data (though typically less). The catalog also includes a second epoch of r band photometry.