Saturday: “The sky is black (or light polluted), the stars are white (or red or orange or yellow or blue), the whole world gazes upon the sight (except where there are too many city lights or people are lazy.” Wow. It is difficult to write a flowing set of lyrics when there are so many parenthetical thoughts. Most people think of the sky’s blackness as a lack of stars. But dark patches in the Milky Way are actually massive clouds of dust that are blocking the stars behind them. Two of the most prominent are dark nebulae B142 and B143 in the constellation Aquila the eagle. These are easy to find and enjoy with binoculars. First find the bright white star Altair, five fists held upright and at arm’s length above the southeastern horizon at 10 p.m. Then move your binoculars up a little bit to the next bright star Tarazed, about one fifth as bright. B142 and B143 are to the upper right of Tarazed. They make an “E” shape in the sky; fitting because American astronomer E. E. Barnard first proposed that these were dust clouds and not simply big spaces between the stars. For more information about dark nebulae, including many more to look at with binoculars, go to https://goo.gl/9tiqdh.
Sunday: Arcturus is two and a half fists held upright and at
arm’s length above the western horizon at 10:00 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.
Monday: Saturn is two fists above the southeastern horizon
at 10:30 p.m. Jupiter is one fist above the eastern horizon at this time.
Tuesday: Deneb is straight overhead at 11:30 p.m. When you
look at Deneb, you are seeing light that left Deneb about 2,600 years ago.
Wednesday: All stars rotate. Our Sun takes a little less than
one Earth month to rotate once on its axis. Astronomers studied the
relationship between mass, stellar rotation, and planetary formation by aiming
NASA’s recently retired Kepler space telescope toward the Pleiades open star
cluster. All 1,000 stars in this group are 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, a half a fist above the east-northeastern horizon at 11:15 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 10:15 p.m.
Friday: Mars is finally rising at a semi-reasonable hour. It
is a half a fist above the east-northeastern horizon at midnight.
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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