C2023 A3 - October 15, 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

Thumbnail of figure from publication
Energy-distributions for 12 solar-type stars and synthetic ubv photometry of the sun
New spectrophotometry for 12 solar-type stars providing virtually complete wavelength coverage between 3288 and 7000 A is reported. Instrumental colors are calculated from the solar irradiance, stellar flux curves, and adopted response functions and are transformed to the UBV system by using observed stellar colors. The resulting solar colors agree well with previously published exact counterparts. Comparison of the irradiance curves for the sun and a similar star reveals no evidence of systematic error in the Balmer-confluence region of the parent stellar flux curves. Transformation equations from this procedure appear to reproduce the UBV system for solar-type stars quite closely. Solar colors are reported for five published irradiance curves and are compared to other photometric solar colors from the literature. Indirect techniques yield solar (B-V) in the range 0.60-0.66.
Thumbnail of figure from publication
An augmented system of secondary standards for bright-star spectrophotometry
This paper contains calibrations on the Hayes-Latham (1975) spectrophotometric system for 21 bright secondary standard stars. Seven of these calibrations are intended for use only with archival data, or the low sensitivity S1 photocathode, or both; the other 14 are for general use in the 3300 to 10,800 A wavelength range. The sky coverage of the calibrated stars is generally adequate for southern hemisphere observers, and is somewhat better than adequate for northern hemisphere observers. At wavelengths shorter than 6058 A, the calibrations include and extend the work of Breger. At wavelengths greater than 6058 A, the most frequently used data are from closely accordant data series given by Cochran (1981) and by the author. A status review is given for 'problem stars' calibrated in this and other papers. Several of these stars are small-amplitude variables, and Zeta Oph and (probably) 109 Vir vary intermittently by amounts which can be substantial. Other problems of calibration or use are discussed. Evidence is reviewed which suggests that, as a whole, the calibrations given in this paper have high accuracy. This implies that several of the calibrated stars may be used as standards each night; the advantages of this technique are described. Future work on secondary standards, and decisions which should be made about them, are reviewed.
Thumbnail of figure from publication
Some evidence for variation of the spectrophotometric standard 109 virginis

The existing spectrophotometric data for the standard star 109 Vir show evidence for intermittent variation during the years 1966-68, and again after 1977. During both epochs, the variation has been of a nature to increase (b — y) and decrease m1 by roughly equal amounts. Evidence for variation of this type also appears in Strömgren data obtained by Perry during the early 1960s. The amount of this latter variation is very similar to that predicted from the later-epoch scans.

Thumbnail of figure from publication
A revised and extended calibration for the spinrad-taylor scanner system
In this paper, new spectrophotometric data are presented for the standards of the Spinrad-Taylor (1969) scanner photometric system. The new data are in the 4040-6180 A wavelength range and are used to construct a calibration of Spinrad-Taylor data to absolute units in this range. In addition, a previously published calibration for wavelengths greater than 6100 A is revised and extended through use of data in the literature. The calibrations, fused into a single whole, and the Spinrad-Taylor data themselves, are tested for systematic error, partly through use of further new spectrophotometry at wavelengths greater than 6100 A; those tests which can currently be made yield generally satisfactory results.
Thumbnail of figure from publication
The TESS Grand Unified Hot Jupiter Survey. III. Thirty More Giant Planets

We present the discovery of 30 transiting giant planets that were initially detected using data from NASA’s Transiting Exoplanet Survey Satellite mission. These new planets orbit relatively bright (G ≤ 12.5) FGK host stars with orbital periods between 1.6 and 8.2 days, and have radii between 0.9 and 1.7 Jupiter radii. We performed follow-up ground-based photometry, high angular resolution imaging, high-resolution spectroscopy, and radial velocity monitoring for each of these objects to confirm that they are planets and determine their masses and other system parameters. The planets’ masses span more than an order of magnitude (0.17 MJ < Mp < 3.3 MJ). For two planets, TOI-3593 b and TOI-4961 b, we measured significant nonzero eccentricities of  and  , respectively, while for the other planets, the data typically provide a 1σ upper bound of 0.15 on the eccentricity. These discoveries represent a major step toward assembling a complete, magnitude-limited sample of transiting hot Jupiters around FGK stars.

Thumbnail of figure from publication
A Survey of Model Fits to Brown Dwarf Spectra Through the L–T Sequence
Savanah K. Turner, Denise C. Stephens, and Josh A. Miller (et al.)

We fit archival near-IR spectra of ∼300 brown dwarfs with atmosphere models from the Sonora and Phoenix groups. Using the parameters of the best-fit models as estimates for the physical properties of the brown dwarfs in our sample, we have performed a survey of how brown dwarf atmospheres evolve with spectral type and temperature. We present the fit results and observed trends. We find that clouds have a more significant impact on near-IR spectra than disequilibrium chemistry, and that silicate clouds influence the near-IR spectrum through the late T types. We note where current atmosphere models are able to replicate the data and where the models and data conflict. We also categorize objects with similar spectral morphologies into families and discuss possible causes for their unique spectral traits. We identify two spectral families with morphologies that are likely indicative of binarity.