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News and Events

Vance Robinson
Friday's Colloquium: Vance Robinson
Please join us for a colloquium titled “ X-ray Sources: Advances in Electron Emitter Technology and Multi-Beam Sources” at 12:00 PM online, or in C215 ESC.
Thumbnail of Stars, Dust, and Gas Near Antares
APOD: Stars, Dust, and Gas Near Antares
Why is the sky near Antares and Rho Ophiuchi so dusty yet colorful? The colors result from a mixture of objects and processes. Fine dust -- illuminated from the front by starlight -- produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark. Antares, a red supergiant and one of the brighter stars in the night sky, lights up the yellow-red clouds on the lower right of the featured image. The Rho Ophiuchi star system lies at the center of the blue reflection nebula on the top left. The distant globular cluster of stars M4 is visible above and to the right of Antares. These star clouds are even more colorful than humans can see, emitting light across the electromagnetic spectrum.
Mount Timpanogos with sky above
Weather at the Eyring Science Center
Check current conditions and historical weather data at the ESC.
Image for Capturing Images at the New Mexico Observatory
Capturing Images at the New Mexico Observatory
Students and faculty from theBYU Astronomy and Physics department captured images from space at an observatory in New Mexico to research explaining the evolution of the universe.
Image for How Physics Students Thrive in a Pandemic
How Physics Students Thrive in a Pandemic
Ways Students have Adapted to the Pandemic
Image for New Professor Dr. Benjamin Boizelle
New Professor Dr. Benjamin Boizelle
Dr. Boizelle brings radio astronomy to the department

Selected Publications

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Proca Q-balls and Q-shells
BYU Authors: Christopher B. Verhaaren, published in J. High Energy Phys.

Non-topological solitons such as Q-balls and Q-shells have been studied for scalar fields invariant under global and gauged U(1) symmetries. We generalize this framework to include a Proca mass for the gauge boson, which can arise either from spontaneous symmetry breaking or via the Stuckelberg mechanism. A heavy (light) gauge boson leads to solitons reminiscent of the global (gauged) case, but for intermediate values these Proca solitons exhibit completely novel features such as disconnected regions of viable parameter space and Q-shells with unbounded radius. We provide numerical solutions and excellent analytic approximations for both Proca Q-balls and Q-shells. These allow us to not only demonstrate the novel features numerically, but also understand and predict their origin analytically.

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An Examination of Pulsational Changes in the Classical Cepheid X Cygni
BYU Authors: Eric G. Hintz, Tyler B. Harding, and Maureen L. Hintz, published in Astron. J.

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.

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Isochrone fitting of Galactic globular clusters – III. NGC 288, NGC 362, and NGC 6218 (M12)
BYU Authors: Aleksandr V Mosenkov, published in Mon. Not. Roy. Astron. Soc.

We present new isochrone fits to colour–magnitude diagrams of the Galactic globular clusters NGC 288, NGC 362, and NGC 6218 (M12). We utilize a lot of photometric bands from the ultraviolet to mid-infrared by use of data from the HST, Gaia, unWISE, Pan-STARRS, and other photometric sources. In our isochrone fitting we use theoretical models and isochrones from the Dartmouth Stellar Evolution Program and Bag of Stellar Tracks and Isochrones for α–enhanced abundance [α/Fe]=+0.40, different helium abundances, and a metallicity of about [Fe/H]=−1.3 adopted from the literature. We derive the most probable distances 8.96 ± 0.05, 8.98 ± 0.06, and 5.04 ± 0.05 kpc, ages 13.5 ± 1.1, 11.0 ± 0.6, and 13.8 ± 1.1 Gyr, extinctions AV = 0.08 ± 0.03, 0.11 ± 0.04, and 0.63 ± 0.03 mag, and reddenings E(B − V) = 0.014 ± 0.010, 0.028 ± 0.011, and 0.189 ± 0.010 mag for NGC 288, NGC 362, and NGC 6218, respectively. The distance estimates from the different models are consistent, while those of age, extinction, and reddening are not. The uncertainties of age, extinction, and reddening are dominated by some intrinsic systematic differences between the models. However, the models agree in their relative age estimates: NGC 362 is 2.6 ± 0.5 Gyr younger than NGC 288 and 2.8 ± 0.5 Gyr younger than NGC 6218, confirming age as the second parameter for these clusters. We provide reliable lists of the cluster members and precise cluster proper motions from the Gaia Early Data Release 3.