A 'New' Star

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

The authors compare their cluster (R-I) data (see the preceding paper) to measurements from other sources. For the Hyades, they find no case in which other data definitely agree with their own in both scale and zero point. For M67, affairs are better, and the authors can compile a merged (R-I) and (V-R) catalog for the evolved stars. These analyses yield one instance of disagreement between sets of Eggen R-I data, and two more in which such data disagree with measurements by others. A fourth example of this kind exists for the Hyades, and a fifth example exists for field stars. The combined evidence suggests that there have been recurring systematics in Eggen's (R-I) measurements.
The authors report new V magnitudes and/or (VRI)C colors for 17 Hyads and 11 bright M67 stars. They find that a source of variation in the Hyads (probably chromospheric variation) can change R-I while leaving V-R unaffected. The V magnitude can also vary, but is uncorrelated with R-I. The timescale for color variation is roughly a week; V magnitudes can vary on timescales from weeks to years.
Benjamin J. Taylor and Scott B. Johnson
This paper considers absorption features in nearby, very strong lined (VSL) G and K stars. These are the stars which traditionally have been called "super-metal-rich" (SMR). The data include measurements made by Spinrad and Taylor, more recent data of the same kind, and a temperature index (Cousins R - I). The other indices adopted measure narrow-band blanketing, broad-band blanketing, and strong absorption features of CN, Ca I, CH, Mg I, and Na I. For dwarfs, data for Fe I and Ca II are also analyzed. It is found that with two exceptions (CH in giants, Ca II in dwarfs), G and K VSL stars have enhancements in all these features. For disk G and K stars in general, there is a positive correlation between the temperature-corrected strengths of most indices. A feature is enhanced in VSL stars if and only if it participates in this correlation. The VSL stars are therefore simply strong-featured examples of disk stars. For non-VSL stars, stronger (weaker) features are associated with higher (lower) overall metallicities. If this correlation applies also to VSL stars, they are super-metal-rich. The authors discuss possibilities which might explain the VSL enhancements without appeal to supermetallicity. None of these "Alternatives X" are clearly satisfactory, but the existence for an Alternative X is not ruled out.
Benjamin J. Taylor, Scott B. Johnson, and Michael D. Joner
The authors report accidental errors and blanketing sensitivities for seven disk K giant temperature indices: Johnson J-K, Cousins R-I, Johnson R-I, Kron R-I, the Spinrad-Taylor T index. T1-T2, and V-K. The authors ultimately compare these indices to a blanketing-free color index, with the latter being derived from narrowband photometry, empirical blocking data, and a model-atmosphere backwarming correction. They also investigate the anomalous R band blanketing reported by Frogel, Whitford, and Rich for Baade's Window K giants.
Scott B. Johnson, Michael D. Joner, and Benjamin J. Taylor
The authors present new data which will contribute to an analysis of the so-called super-metal-rich K giants. The results include DDO photometry and photomultiplier scanner data; some of the latter reflect blanketing and feature strengths, and the rest bear primarily on stellar temperatures. Some of the scanner data are transformed to the Cousins R-I system and are given with previously published measurements on this system.
Transformations among VRI systems are commonly beset by Paschen-jump effects, for which fully satisfactory allowance has not previously been made. This paper describes two new techniques which are based on the work of Gutierrez-Moreno, and which allow fully for the effects of the Paschen jump. Values of E(V-R)/E(B-V) and E(R-I)/E(B-V) are also given for the Cousins system for a wide range of temperatures. These and the new techniques contribute to a set of new transformation relations which apply for most VRI systems; the status of the remaining systems is reviewed, and future work needed for them is described. Two major sources of Cousins VRI data underlie the new relations; the consistency of these sources is reviewed and found to be generally satisfactory, although more work on this question is needed. Finally, three tables of transformed standard-star and other data are given for the Cousins and Johnson systems, and a description of ways to reproduce the latter is presented.