West Mountain, Moon, Venus, and Stars

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

We present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright (V ∼ 11.1) Sun-like G2V star TYC 7518-468-1. The planet has an orbital period of days, a radius of , and a relatively large mass of . The star has , , K, (cgs), and [m/H] = ; thus other than its slightly super-solar metallicity, it appears to be a near-solar twin. Surprisingly, KELT-22A exhibits kinematics and a Galactic orbit that are somewhat atypical for thin-disk stars. Nevertheless, the star is rotating rapidly for its estimated age, and shows evidence of chromospheric activity. Imaging reveals a slightly fainter companion to KELT-22A that is likely bound, with a projected separation of 6″  (∼1400 au). In addition to the orbital motion caused by the transiting planet, we detect a possible linear trend in the radial velocity of KELT-22A, suggesting the presence of another relatively nearby body that is perhaps non-stellar. KELT-22Ab is highly irradiated (as a consequence of the small semimajor axis of ), and is mildly inflated. At such small separations, tidal forces become significant. The configuration of this system is optimal for measuring the rate of tidal dissipation within the host star. Our models predict that, due to tidal forces, the semimajor axis is decreasing rapidly, and KELT-22Ab is predicted to spiral into the star within the next Gyr.

Ian R. Clark, Eric G. Hintz, Michael D. Joner, Trevor J. Martin, Alex D. Spencer, Michelle Spencer, and Denise C. Stephens (et al.)
The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ∼23″ pixel −1 —very similar to that of NASA’s Transiting Exoplanet Survey Satellite ( TESS )—as well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3′. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and photometric precision higher than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ∼450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1128 bright stars(6 < V < 13) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS .
Seth P. Clarke, Michelle Spencer, Jason Trump, Michael D. Joner, Adam G. Bugg, Eric G. Hintz, and Denise C. Stephens (et al.)
We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of ${1.586}_{-0.040}^{+0.039}$ $\,{R}_{{\rm{J}}}$. We set an upper limit on the planetary mass of ${M}_{P}\lt 3.91$ $\,{M}_{{\rm{J}}}$ at $3\sigma $ confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin–orbit misalignment of $\lambda =-{5.6}_{-1.9}^{+1.7\circ }$. The star has ${T}_{\mathrm{eff}}={7598}_{-84}^{+81}$ K, ${M}_{* }={1.458}_{-0.028}^{+0.029}\,\,{M}_{\odot }$, ${R}_{* }=1.638\,\pm 0.034\,\,{R}_{\odot }$, and $v\sin {I}_{* }=146$ km s−1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal poor and α-enhanced, with $[\mathrm{Fe}/{\rm{H}}]=-{0.405}_{-0.033}^{+0.032}$ and [α/Fe] = 0.145 ± 0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1farcs2 and with a combined contrast of ${\rm{\Delta }}{K}_{S}=6.39\pm 0.06$ with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of ~0.12 $\,{M}_{\odot }$, a projected mutual separation of ~20 au, and a projected separation of ~500 au from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems.

We present the discovery of the giant planet KELT-19Ab, which transits the moderately bright () A8V star TYC 764-1494-1 with an orbital period of 4.61 days. We confirm the planetary nature of the companion via a combination of  radial velocities, which limit the mass to (), and a clear Doppler tomography signal, which indicates a retrograde projected spin–orbit misalignment of degrees. Global modeling indicates that the K host star has and . The planet has a radius of and receives a stellar insolation flux of , leading to an inferred equilibrium temperature of K assuming zero albedo and complete heat redistribution. With a , the host  is relatively slowly rotating compared to other stars with similar effective temperatures, and it appears to be enhanced in metallic elements but deficient in calcium, suggesting that it is likely an Am star. KELT-19A would be the first detection of an Am host of a transiting planet of which we are aware. Adaptive optics observations of the system reveal the existence of a companion with late-G9V/early-K1V spectral type at a projected separation of . Radial velocity measurements indicate that this companion is bound. Most Am stars are known to have stellar companions, which are often invoked to explain the relatively slow rotation of the primary. In this case, the stellar companion is unlikely to have caused the tidal braking of the primary. However, it may have emplaced the transiting planetary companion via the Kozai–Lidov mechanism.

We report the discovery of KELT-20b, a hot Jupiter transiting a $V\sim 7.6$ early A star, HD 185603, with an orbital period of $P\simeq 3.47$ days. Archival and follow-up photometry, Gaia parallax, radial velocities, Doppler tomography, and AO imaging were used to confirm the planetary nature of KELT-20b and characterize the system. From global modeling we infer that KELT-20 is a rapidly rotating ($v\sin {I}_{* }\simeq 120\,\mathrm{km}\ {{\rm{s}}}^{-1}$) A2V star with an effective temperature of ${T}_{\mathrm{eff}}={8730}_{-260}^{+250}$ K, mass of ${M}_{* }={1.76}_{-0.20}^{+0.14}\ \,{M}_{\odot }$, radius of ${R}_{* }={1.561}_{-0.064}^{+0.058}\ \,{R}_{\odot }$, surface gravity of $\mathrm{log}{g}_{* }={4.292}_{-0.020}^{+0.017}$, and age of  $\lesssim 600\,\mathrm{Myr}$. The planetary companion has a radius of ${R}_{P}={1.735}_{-0.075}^{+0.070}\,\,{R}_{{\rm{J}}}$, a semimajor axis of $a={0.0542}_{-0.0021}^{+0.0014}$ au, and a linear ephemeris of ${\mathrm{BJD}}_{\mathrm{TDB}}=2457503.120049\pm 0.000190$ $+E(3.4741070\pm 0.0000019)$. We place a $3\sigma $ upper limit of $\sim 3.5\,\,{M}_{{\rm{J}}}$ on the mass of the planet. Doppler tomographic measurements indicate that the planetary orbit normal is well aligned with the projected spin axis of the star ($\lambda =3\buildrel{\circ}\over{.} 4\pm 2\buildrel{\circ}\over{.} 1$). The inclination of the star is constrained to $24\buildrel{\circ}\over{.} 4\lt {I}_{* }\lt 155\buildrel{\circ}\over{.} 6$, implying a three-dimensional spin–orbit alignment of $1\buildrel{\circ}\over{.} 3\lt \psi \lt 69\buildrel{\circ}\over{.} 8$. KELT-20b receives an insolation flux of $\sim 8\times {10}^{9}\,\mathrm{erg}\,{{\rm{s}}}^{-1}\,{\mathrm{cm}}^{-2}$, implying an equilibrium temperature of of ~2250 K, assuming zero albedo and complete heat redistribution. Due to the high stellar ${T}_{\mathrm{eff}}$, KELT-20b also receives an ultraviolet (wavelength $d\leqslant 91.2$ nm) insolation flux of $\sim 9.1\times {10}^{4}\,\mathrm{erg}\,{{\rm{s}}}^{-1}\,{\mathrm{cm}}^{-2}$, possibly indicating significant atmospheric ablation. Together with WASP-33, Kepler-13 A, HAT-P-57, KELT-17, and KELT-9, KELT-20 is the sixth A star host of a transiting giant planet, and the third-brightest host (in V) of a transiting planet.
Mary T. Dumont, Clement Gaillard, Kyle Matt, Denice C. Stephens, and Michael D. Joner (et al.)
The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300–10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside2, and is highly inflated–traits that have been linked to high insolation3, 4. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.