Thursday, August 22, 2019

The Ellensburg, WA sky for the week of August 24, 2019

Saturday: Arcturus is three fists held upright and at arm’s length above the western horizon at 9:30 p.m. This star, whose name means bear watcher, is the brightest in the sky’s northern hemisphere. It follows Ursa Major, the Great Bear, around the North Star. Arcturus is the closest giant star to Earth. It is one of the few stars whose diameter can be measured directly rather than being inferred from its density and mass, which themselves are derived from other parameters.

Sunday: Have you ever gone to a family reunion, looked around and asked, “How in the world are we related to each other?” Astronomers look around the Solar System and wonder if there is life anywhere else that we are related to. The Mars Science Laboratory landed on Mars in 2012 to investigate whether it ever had conditions favorable for life. The Venus Express studied the atmosphere of Venus from 2006 to 2014. NASA plans to launch the Europa Clipper in 2023 to look for evidence of current or past life in the Jovian moon’s ice-covered ocean. And NASA just approved the Dragonfly mission to fly a drone through the atmosphere of Saturn’s moon Titan to study clues for the origin of life. To learn more about the search for life in the Solar System and beyond, go to https://www.astrobio.net/, a NASA-sponsored popular science magazine. While you won’t see anyone waving back, you can see Jupiter and Saturn in the evening sky. At 9:00 p.m., Jupiter is nearly two fists above the south-southwestern horizon and Saturn is two fists above the southern horizon.

Monday: Deneb is nearly straight overhead at 11 p.m. When you look at Deneb, you are seeing light that left Deneb about 1,800 years ago.

Tuesday: Spica, the brightest star in the night sky, is about a half a fist above the southeastern horizon at 5:30 a.m.

Wednesday: All stars rotate. Our Sun takes a little less than an Earth month to make one rotation. Astronomers have started to study the relationship between mass, stellar rotation, and planetary formation by aiming NASA’s Kepler space telescope toward the Pleiades open star cluster. All 1,000 stars in this group is nearly the same age, 125 million years old. Since all of the stars are the same age and formed from the same set of materials, astronomers have the ideal “laboratory” to isolate the role star mass plays on star rotation and evolution. Read more about the findings at http://goo.gl/osijIY. See the Pleiades for yourself, one fist above the east-northeastern horizon at 11:30 p.m.

Thursday: Seventeenth century astronomers documented the appearance of a new star, or “nova”, in 1670. However as modern astronomers studied the records of the star, called Nova Vulpeculae 1670, they realized it didn’t have the characteristics of a typical nova because it didn’t repeatedly brighten and dim. It brightened twice and disappeared for good. Turning their telescopes to the region, they discovered the chemical signature to be characteristic of a very rare collision of two stars. For more information about this discovery, go to http://goo.gl/rJnC2G. Nova Vulpeculae 1670 is right below the binary star system Alberio, the head of Cygnus the swan. Alberio is seven fists above due south at 10:00 p.m.

Friday: Today’s new Moon is at perigee, meaning it is at its closest point to the Earth for the month. When the Moon is closer to the Earth, its gravitational tug is greater and the tides are higher. So that means the tides will be exceptionally high today.


The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm

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