Saturday: At 9:30 p.m., the bright star Regulus is to the lower right of the crescent moon, low on the west-northwestern horizon. Mars is nearby, one fist held upright and at arm’s length above the western horizon.
Sunday: Have you ever planned a vacation to a place because
it was supposedly the up-and-coming locale? Then, when the vacation time
finally arrives, you find out the place doesn’t live up to its billing. Over
the past decade, astronomers strengthened earlier findings about the planetary
system of the star Tau Ceti, one of our closest Sun-like star neighbors at 12
light years away. It has four planets classified as “super-Earths.” Two of the
planets are on the edge of the habitable zone where the temperature is just
right for having liquid water on their surface. Time for a va-ca-tion! Well,
not so fast. Astronomers have only a lower limit to the planet masses so they
may be too massive for complex life to form. And the Tau Ceti system has ten
times as much mass in dust and rocks as our own solar system. So, you’ll want
to do some research before you travel there. Tau Ceti is one and a half fists
above the southeast horizon at 3:00 a.m. For more information about the system,
go to https://skyandtelescope.org/astronomy-news/four-exoplanets-may-orbit-nearby-sun-like-star/.
Monday: Saturn is a half a fist above the eastern horizon at
11:30 p.m.
Tuesday: The Southern Delta Aquarid meteor shower peaks
tonight, tomorrow night, and on into mid-August. Meteor showers are named after
the constellation from which the meteors appear to originate. These meteors
appear to come from a point in Aquarius near the star Delta Aquarii, also known
as Skat. This point is about one and a half fists above the southeastern
horizon at 1:00 am tonight. You can follow this point throughout the night, as
it will remain a fist above Fomalhaut, the brightest star in that section of the
sky. The Moon is in the waxing crescent to first quarter phase this week
meaning it will not be up for many hours each night. For more information about
this year’s shower, go to https://earthsky.org/?p=159138.
As your mother might say, dress warmly and sit in a comfortable chair for
maximum enjoyment. Meteors are tiny rocks that hit the Earth and burn up in the
atmosphere.
Wednesday: At 4:30 a.m., Jupiter is one fist above the
east-northeastern horizon and Venus is one and a half fists above the eastern
horizon.
Thursday: Mizar is a well-known binary star in the
constellation Ursa Major. You can find it at the bend in the Big Dipper handle,
three fists above due northwest at midnight. Its name is Arabic for waistband.
Mizar has an optical double called Alcor, which is less than a pinky width away
and can easily be seen with the naked eye. Optical doubles are stars that are
close together in the sky but do not orbit a common center of mass as true
binary stars. Not wanting to deceive sky gazers who call Alcor and Mizar a
binary star, two stars that DO orbit a common center of mass, Mizar actually is
a binary. It was the first binary star system discovered using a telescope.
Mizar A and Mizar B are about 400 astronomical units apart from each other and
about 80 light years from Earth. 400 astronomical units is about 10 times the
distance between the Sun and Pluto.
Friday: The Perseid meteor shower peaks in a week and a
half. But there will be an increased number of meteors over the next two weeks.
If the Moon is out when you want to look, position yourself so you are blocked
from the Moon’s light. The meteors appear to come from a point just below the W
of the constellation Cassiopeia. This point is about two and a half fists above
the northeast horizon at 11:00 p.m. By dawn, this point is about seven fists
above the northeast horizon. If you fall asleep or forget to set your alarm,
you will be able to observe this shower from about 11:00 p.m. to dawn for the
next two weeks in about the same location in the sky.
The Perseid shower is one of the longest lasting showers.
For tips about optimizing your viewing this year, go to https://earthsky.org/?p=165416. These
meteors are sand to pea-sized bits of rock that fell off Comet Swift-Tuttle.
They travel about 40 miles per second as they collide with the Earth and burn
up in the atmosphere.
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.
All times are Pacific Time unless noted.
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