Bakersfield Night Sky – August 15, 2015
By Nick Strobel
School begins in a few days for many K12 students and next week for Bakersfield College, so my household is very school focussed now. This is the last summer "vacation" weekend for us. The kids aren't ready to go back to school but my wife and I sure are.
Two things to put on your calendar are the KAS public star party next Saturday, August 22nd, and the Dark Sky Festival at Sequoia National Park the weekend of September 11th to 13th. The Kern Astronomical Society will be hosting a free public star party at Panorama Bluff Park on Saturday, August 22nd from 8 to 10 PM. Telescopes will be set up near where Linden Ave runs into Panorama Drive. The Moon and Saturn will be bright targets to see along with beautiful star clusters and nebulae.
Tonight the Moon is a very thin Waxing Crescent just one day past New Phase, setting a few minutes after the Sun does but next Saturday it will be at First Quarter, so it will appear half-lit and the craters will be especially noticeable through the KAS telescopes. On August 22nd the Moon will be just above the head of Scorpius in the southern sky at sunset. A bit to the right of the Moon between Scorpius and Libra will be Saturn. Saturn will be 90 degrees from the Sun that weekend, so the shadow of the globe on the rings will be at its maximum extent. A great sight to see through the KAS telescopes!
Left (east) of Scorpius are the stars of Sagittarius. That is the direction toward the center of the Milky Way, so the thickness of the Milky Way's band is thickest in the direction of Sagittarius (and the 13th zodiac constellation above it, Ophiuchus). While the skies of Bakersfield are a bit too polluted to see the Milky Way, there are plenty of relatively young open clusters, old globular clusters and gas nebulae in the direction of Sagittarius and Scorpius (and Ophiuchus) to view through the KAS telescopes.
High almost directly overhead will be Hercules with the famous globular cluster M13 on its right (west) side. High up in the southeast will be Summer Triangle formed by the three brightest stars in Cygnus, Aquila, and Lyra: Deneb, Altair, and Vega. On the opposite end of Lyra from Vega, you can get a view of what our solar system will look like about 7 billion years from now with the Ring Nebula.
Three weekends later on September 11 through 13, the Sequoia Natural History Association will be presenting the Dark Sky Festival at Sequoia National Park. There will be a number of activities during the day AND night. The listing of activities on the Dark Sky Festival website at www.sequoiahistory.org/darksky includes constellation tours, telescope viewings, solar observations, astronaut Robert L Behnken, kids activities, NASA Systems Engineer Nagin Cox, model rocket building (hopefully no flames, though), National Park Service programs, special Crystal Cave tours, nature walks, photography presentations, and musical performances. I don't know the topic of astronaut Robert Behnken's talk but he is one of the four astronauts training for the first US commercial space flight, so he may include that upcoming space flight in his talk. Nagin Cox is a systems engineer for the NASA Curiosity mission on Mars, so she'll have plenty of things to share about our current and future explorations of Mars. The Kern Astronomical Society will be giving solar observing sessions at two locations on Saturday followed by a star party at one location that night.
The skies of Sequoia and Kings National Parks are truly dark and there will be no Moon to worry about, so you'll be able to see thousands of stars and the Milky Way. The cost to attend the Dark Sky Festival is just the park entrance fee. Last year, the KAS folks had many hundreds of people (at least) from many different countries (one KAS member counted 8 countries last year) viewing the sky through their telescopes and there will very likely be even more people attending this year.
One interesting piece of recent astronomy news is the detection of the closest rocky "super-Earth" to us. If you have a dark sky, you can actually see the star it orbits without a telescope in the northern constellation Cassiopeia. The star is just 22 light years away---in our backyard, astronomically speaking. In the context of exoplanet research, a "super-Earth" is defined by mass only: a world up to ten times the mass of Earth. The term does not necessarily mean the planet is habitable. The upper limit of ten times the mass of Earth is used because it is thought that planets larger than 10 times the mass of Earth will have enough gravity to suck up the hydrogen and helium surrounding it as it is forming and become a jovian planet, like Neptune or Jupiter.
The stats for this exoplanet with the very sexy name of "HD 219134b" are: mass between 4 and 5 times the Earth's mass and about 1.6 times the Earth's diameter. This puts its density somewhere between 4.7 and 7 times that of water which means it is definitely made of rock and metals like the terrestrial planets, including Earth. Earth's density is 5.5 times that of water and that is the highest of any of the planets in our solar system. This rocky super-Earth is much too close to its star though to be habitable. It takes just 3 days to orbit its star! There are two other super-Earths in the HD 219134 system but we haven't been able to measure their diameters yet. We only know their masses. Both diameter and mass are needed to give us the density and it's the density that gives us the composition.
By the way, the closest exoplanet to us is Alpha Centauri Bb at just 4.23 light years away.
Want to see more of the stars at night and save energy? Shield your lights so that the light only goes down toward the ground. See www.darksky.org for how.
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Nick Strobel
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com