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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Christiana Z. Suggs, Eric G. Hintz, and Denise C. Stephens

As part of our variable star follow-up program, we have examined a number of stars from the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey. Using a combination of our own data, ATLAS data, and other archival data, we confirmed the published periods and established a baseline ephemeris for each star. This initial sample of six stars are from the PUL or mono-periodic set from the ATLAS survey. Our determined periods agreed well with the published values. Five targets were found to be high amplitude δ Scuti variables (HADS), and one a low-amplitude δ Scuti (LADS). Beyond the primary period we examined the frequency content, Q value, position in the PL relation, and position within the instability strip of each object. We found ATO J070.9950+37.4038 to be the most complex target. The frequency content is likely a set of nonradial pulsations. ATO J328.8034+58.0406 is a multiperiodic HADS variable that is pulsating in the first and second overtones. ATO 345.4240+42.0479 was found to be a simple HADS monoperiodic fundamental pulsator. In the case of ATO J086.0780+30.3287, we found a strong fundamental pulsation with many harmonics and a weaker first overtone pulsation. We classify ATO J086.0780+30.3287 as a HADS. ATO J077.6090+36.5619 was found to be an interesting case of a monoperiodic star that appears to be pulsating in the third overtone. The lower amplitude for this target would put it in the LADS group. ATO J045.8159+46.0090 was found to be a multiperiodic HADS pulsating in the first and second overtones.

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Tyler B. Harding and Eric G. Hintz

Spectroscopic methods were used to monitor the Hα and Hβ indices for two emission-line objects, X Persei and γ Cassiopeiae. The spectroscopic data covered a timeline from 2010 to 2020. The Hα index for X Per showed substantial variation, with the Hβ index changes being less pronounced. The shape of the Hα variations for X Per were a mirror image to archival V-magnitude observations. In the case of γ Cas only a slight rise in value for the Hα index was seen. To allow comparison to published observations, we determined a transformation from the two indices to equivalent width values. The values determined for X Per fill time gaps in the previously published equivalent width values. The γ Cas values provide no additional coverage.

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Denise C Stephens, Emma Campbell, Jarrod Hansen, Eric G Hintz, and Jacob S Jensen (et al.)

We present the discovery and characterization of six short-period, transiting giant planets from NASA’s Transiting Exoplanet Survey Satellite (TESS) — TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), & TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9 <G < 11.8, 7.7 <K < 10.1). Using a combination of time-series photometric and spectroscopic follow-up observations from the TESS Follow-up Observing Program (TFOP) Working Group, we have determined that the planets are Jovian-sized (RP = 0.99-1.45 RJ), have masses ranging from 0.92 to 5.26 MJ, and orbit F, G, and K stars (4766 ≤ Teff ≤ 7360 K). We detect a significant orbital eccentricity for the three longest-period systems in our sample: TOI-2025 b (P = 8.872 days, 0.394$^{+0.035}_{-0.038}$), TOI-2145 b (P = 10.261 days, e = $0.208^{+0.034}_{-0.047}$), and TOI-2497 b (P = 10.656 days, e = $0.195^{+0.043}_{-0.040}$). TOI-2145 b and TOI-2497 b both orbit subgiant host stars (3.8 < log  g <4.0), but these planets show no sign of inflation despite very high levels of irradiation. The lack of inflation may be explained by the high mass of the planets; $5.26^{+0.38}_{-0.37}$ MJ (TOI-2145 b) and 4.82 ± 0.41 MJ (TOI-2497 b). These six new discoveries contribute to the larger community effort to use TESS to create a magnitude-complete, self-consistent sample of giant planets with well-determined parameters for future detailed studies.

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Eric G. Hintz, Jarrod L. Hansen, Denise C. Stephens, and Benjamin J. Derieg

As part of our variable star follow-up program we have examined a number of stars from the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey. The first of these, ATO J031.2309+52.9923, was reported with a period of 0.069705 d. Our revised period is 0.06970555 d, but we find an additional period of 0.074 d. We also report a suspected period change of (1 / P) dP / dT = –340 × 10–8 yr–1. In addition to the primary period, we find two additional closely spaced periods of 0.07380 d and 0.07338 d, with a period ratio of P1 / P2 = 0.945. The period ratio and change would indicate that this object is a δ Scuti variable with non-radial pulsations. We find that this target fits into the medium amplitude group of δ Scuti variables such as AN Lyncis.

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We report the first discovery of a transiting circumbinary planet detected from a single sector of Transiting Exoplanet Survey Satellite (TESS) data. During Sector 21, the planet TIC 172900988b transited the primary star and then five days later it transited the secondary star. The binary is itself eclipsing, with a period P approximate to 19.7 days and an eccentricity e approximate to 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of M (1) = 1.2384 +/- 0.0007 M (circle dot) and R (1) = 1.3827 +/- 0.0016 R (circle dot) for the primary and M (2) = 1.2019 +/- 0.0007 M (circle dot) and R (2) = 1.3124 +/- 0.0012 R (circle dot) for the secondary. The radius of the planet is R (3) = 11.25 +/- 0.44 R (circle plus) (1.004 +/- 0.039R (Jup)). The planet's mass and orbital properties are not uniquely determined-there are six solutions with nearly equal likelihood. Specifically, we find that the planet's mass is in the range of 824 less than or similar to M (3) less than or similar to 981 M (circle plus) (2.65 less than or similar to M (3) less than or similar to 3.09M (Jup)), its orbital period could be 188.8, 190.4, 194.0, 199.0, 200.4, or 204.1 days, and the eccentricity is between 0.02 and 0.09. At V = 10.141 mag, the system is accessible for high-resolution spectroscopic observations, e.g., the Rossiter-McLaughlin effect and transit spectroscopy.

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Eric G. Hintz, Tyler B. Harding, and Maureen L. Hintz

Using an extensive archive for visual observations from the AAVSO, along with published times of maximum light, we determined a new model for the period of X Cygni. The best model is two linear fits for data before and after 1917 (JD2421512). Before that time the period is 16.38438 +/- 0.00036 days. After we find a period of 16.386470 +/- 0.000028 days. An examination of the O-C values for data after 1917 shows no clear evidence of a constant period change or of sinusoidal variations. The period looks to be constant. From an examination of H-alpha index measurements we find a drop in the value between data before 2013 October and data after 2014 July. This drop is not related to temperature and is likely related to mass loss in the star. Finally, we find that radial-velocity measurements match well with previously published values and show no seasonal variation over the 11 yr of data. This again seems to limit the possibility of a companion.