Saturday: Mercury and Venus are low on the west-northwestern horizon right after sunset. Venus is the brighter of the two. Mercury is a fist to the left of Venus at 9:10 p.m. The star Regulus is to the upper right of Mercury.
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. Seven
years ago this month, astronomers strengthened earlier findings that the star
Tau Ceti, one of our closest neighbors at 12 light years away, has four planets
classified as “super-Earths”. Two of the planets are in the so-called 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 discovery, go to https://skyandtelescope.org/astronomy-news/four-exoplanets-may-orbit-nearby-sun-like-star/.
Monday: The Southern Delta Aquarid meteor shower peaks
tonight 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, and
a first to the lower right of Saturn. The Moon is approaching the new moon
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 warm and sit in a comfortable chair for maximum
enjoyment. Meteors are tiny rocks that hit the Earth and burn up in the
atmosphere.
Tuesday: Clockwise from the top, the moon, Mars, the star
Aldebaran, and Jupiter make a crooked diamond shape three and a half fists
above due east at 5:00 a.m.
Wednesday: The bright star Altair is four fists above the
southeastern horizon at 10:00 p.m.
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 in the
Moon’s shadow. 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 held upright
and at arm’s length 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
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 of Comet
Swift-Tuttle. They are traveling 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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