A recent article that appeared in the Astronomical Journal (Joner and Hintz, 2015, AJ, 150, 204), established a new photometric system based on a pair of filter functions used to measure the strength of the H-alpha line in stars. The paper presented H-alpha and H-beta indices for 136 field and cluster stars that were observed with the 1.2-meter telescope at the Dominion Astrophysical Observatory during an 11 year period. The indices were determined from spectro-photometry of the thousands of spectra exposures. The figure to the left shows a relation for normal main sequence stars between the new H-alpha index and the more than 60 year old H-beta index. Color-color plots like this one are useful in surveys to detect objects of astrophysical interest that display emission features of various strengths. These extreme objects are easily seen in a color-color plot. One High Mass X-ray Binary recently observed for a followup study was located at (0.87,1.87) in the color-color plot.
The small black spot projected on the Sun just above the foreground clouds in Provo is caused by the planet Venus as it transits for the last time this century. The transits of Venus come in pairs separated by eight years that only occur after a period of 105 or 122 years without a transit visible from the Earth. If you missed this event, the next opportunity will be in December of 2117. Finding the transit of an Earth sized planet across a stellar photosphere was the primary mission of the Kepler spacecraft as it searched for extrasolar planets up through August 2013. The difficulty of this mission is apparent when you note the small fraction of the Sun's light that is blocked by the transit of a planet the size of Venus.
This composite image of the Dumbbell Nebula (known by catalog designations such as M27 or NGC 6853), located in the northern summer constellation of Vulpecula, presents a remarkably detailed view of the planetary nebula that was first discovered by Charles Messier in 1764. The complex shells of gas that are observed in planetary nebulae are in fact the remnants of material lost by an aging star that has collapsed to form a white dwarf. In the case of the Dumbbell Nebula, the expansion rate of the material surrounding the central star indicates that the main portion of the nebulosity is only three or four thousand years old. Noted astrophysical image processor Dr. Robert Gendler has combined image data from the 2.4-meter Hubble Space Telescope, the 8.2-meter Subaru Telescope located near the summit of Mauna Kea on the island of Hawai’i, and the 0.9-meter Brigham Young University Telescope at the West Mountain Observatory in Utah to produce a rich and finely detailed image of this well known object. The data from the Hubble Space Telescope provide the small scale detail in the central portions of the nebula. The Subaru Telescope data add to the overall fine detail that is resolved in the nebula. The data from the wide field 0.9-meter Brigham Young University Telescope were secured in the summer of 2010 by BYU astronomers Dr. Michael D. Joner and Dr. C. David Laney. The BYU images provide the majority of the color information and faint details in the outer shells of the nebulosity that were used in the assembly of this intricately detailed image.
The figure shown to the left is from a recent publication in the Astronomical Journal (Oberst, Thomas E., et al., 2017, AJ, 153, 97) that confirms the discovery of a highly irradiated, ultra-short period hot Jupiter in orbit around a distant star. The newly discovered planet has been designated as KELT–16b. The long time series run in the left hand panel that is labeled "Pratt" is from a team of students led by Dr. Denise Stephens using the BYU campus Orson Pratt Observatory. The four multi-color data sets that follow were secured a couple of days later by students under the direction of Dr. Michael Joner at the BYU West Mountain Observatory. These and the other data presented in the paper confirm the sub-stellar mass and other properties of KELT-16b.
This image was secured just after the end of evening twilight on a clear April night from the West Mountain Observatory. The view is looking west past the domes housing the two smaller research telescopes at the observatory. The thin crescent Moon is also illuminated by reflected light from the Earth that is known as earthshine. Higher in the sky, the bright 'star' is actually the planet Venus. In between the two, the 'V' shaped group of stars in the constellation of Taurus is in reality the nearby open cluster known as the Hyades. Photo credit: Dr. Michael D. Joner
15 Jan, Today
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Brent Reichman, Kent Gee, and Traci Neilsen et al. recently published an article titled "Characterizing acoustic shocks in high-performance jet aircraft flyover noise" in Journal of The Acoustical Society of America. Click on the image above to read it.
The Heart and Soul Nebulas : Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found....
This photograph and Description come from NASA's Astronomy Picture of the Day web site.