Week of January 13, 2014
This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, January 13. All times are given as local St. Louis time (Central Standard Time). For definitions of terminology used in the night sky update, click the highlighted text.
Information updated weekly or as needed.
Join us for our next star party, Friday, February 7, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.
The Sun and the Moon
Sunrise is at 7:18 a.m. on Monday, January 13 and sunset is at 5:02 p.m. providing us with less than 10 hours of daylight. Even after sunset, the light from the Sun will still illuminate our sky for about one hour and 30 minutes. This period of time is called twilight, which ends around 6:35 p.m. this week. For those with a sun dial, solar transit or local noon occurs around 12:10 p.m. this week.
Moonrise for Monday, January 13 occurs at 3:17 p.m. Moonset will occur at 5:53 a.m. on the following day. On Monday the 13th the Moon will be exhibiting a waxing gibbous phase with roughly 95% of the lunar disk illuminated. Full moon occurs on Wednesday, January 15. January’s full moon is known as the Full Wolf Moon.
International Space Station (ISS) Observing
The next visible passes of ISS over St. Louis are all morning passes. Learn more about these passes and others this week in the table below.
Catch ISS flying over St. Louis in the morning hours starting Monday, January 13.
Magnitude (Mag): The Measure of brightness for a celestial object. The lower the value is, the brighter the object will be.
Altitude (Alt): The angle of a celestial object measured upwards from the observer’s horizon.
Azimuth (Az): The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.
For information about ISS flyovers and other visible satellites, visit www.heavens-above.com
Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:
The Planets Visible Without A Telescope
Mars is now in the constellation Virgo and will rise around 11:47 p.m. this week. For those awake around 2:00 a.m. look to the east and you will see a reddish-orange object high in the eastern skies. Mars will be seen earlier each week as we start to catch up with it in our orbit. Mars will be close to us again in 2014 reaching opposition on April 8, 2014. Fans of Mars rejoice it is back and on its way to another close approach.
Jupiter is now rising as the Sun is setting. For those with a clear eastern horizon look east roughly 30 minutes after sunset and you should see Jupiter shining brighter than any star in the sky. As twilight fades you will see the bright stars Castor and Pollux just north of Jupiter. Looking at these stars and then comparing them to Jupiter you will see that the stars are twinkling and Jupiter is not. The twinkling you see is called scintillation which is a distortion of the stars light by Earth’s atmosphere. Testing for scintillation is how you can distinguish stars from planets.
Saturn is now out of the glare of the Sun. It rises by 2:40 a.m. and will be an easy target by 3:30 a.m. Saturn is currently in the constellation Libra. It forms a nice triangle in the sky with Libra’s two brightest stars Zubenelgenubi and Zubeneschamali.
Comet Lovejoy has been a treat for binocular observers since October 2013. It reached perihelion on December 22, 2013 brightening to about 4.3 magnitude. It still remains an object of interest for those with binoculars or small telescopes and can be seen in the morning skies by 5:00 a.m.
To locate Comet Lovejoy you will need to find the summer constellation Hercules in the eastern skies. An easy way to find Hercules is to locate the Big Dipper, follow the curve of its handle to the bright star Arcturus. This star marks the bottom of the kite shaped constellation Bootes. Look to the east of the widest part of Bootes kite shape and you first find a U-shape of stars and further down you will see a bowtie shape of stars. This bowtie shape is the body of Hercules. Next locate the star Sarin also named Delta Herculis and the star Rasalhague in Ophiuchus. Comet Lovejoy will be following a path between these stars through most of January 2014. For a detailed map follow the link below.
Now that Comet Lovejoy has passed perihelion it will continue to fade becoming more difficult to see each night. It is currently a 6th magnitude comet that is predicted to fade to 8 magnitude by February 2014. Take a look at this comet before it fades from view.
Constellation of the Month
Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation. At the start of the month we will list only a few of these objects and each week we will add another to the list. Some objects will be visible to the unaided eye and some may require a telescope. Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties. Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section.
For January the constellation of the month will be Orion the Hunter. Orion was the great hunter from Greek mythology that was killed by the great scorpion Scorpius. The pair was immortalized in the sky as constellations and is placed opposite one another in the sky. Throughout the year you can see both Orion and Scorpius chasing one another as Orion is in the winter sky and Scorpius is in the summer sky.
Orion is the most prominent constellation in the winter sky. By the time the Sun is setting Orion is beginning to rise in the southeast. By 5:30 p.m. Orion has cleared the horizon and the brightest stars are starting to shine through the twilight sky. Orion has a very distinct hourglass shape with three stars cutting across the middle. These three stars are Orion’s famous belt and are what most look for when searching for the constellation. The most prominent stars in Orion are Betelgeuse, Bellatrix, Rigel, Saiph and the three belt stars Mintaka, Alnilam and Alnitak. Orion will be in the sky from sunset to sunrise and will serve as the starting point for exploring the winter sky.
The first thing we will explore in Orion is the bright star Betelgeuse. This star marks the left shoulder of Orion and stands out amongst the rest due to its bright red color. Betelgeuse is a highly evolved red supergiant star that is beginning the process that ends in a spectacular explosion. The red color is the result of a core collapse event that allowed the outer layers of the star to expand and cool off significantly until core fusion started again. Over the next million years or so this process will continue fusing heavier elements each time. Once the element iron is reached core collapse is inevitable and Betelgeuse will explode in what is called a Type II supernova. These are rare events as they require a single massive star with a mass of 8 to 50 solar masses. Stars this big are not common and therefore Type II supernovas are rare events. In fact in all of recorded history only 6 bright supernovas have been witnessed by humans. The nuclear fusion process occurring in all stars is how all elements heavier the hydrogen and helium are synthesized. Fusion can only account for elements up to iron, everything heavier than iron was synthesized during a supernova. All the precious metals on the earth like those used for jewelry and circuit components were created by the violent explosion of a massive star.
Betelgeuse is under 10 million years old. This short stellar life is the result of its mass and temperature. Betelgeuse was originally a hot massive O or B class star that was associated with the stars in Orion’s belt. At some point Betelgeuse was ejected from the OB association in Orion’s belt and is speeding away at about 30 km/s.
To find Betelgeuse look for the bright red star in the top left corner of the constellation. It will be impossible to miss as it is the 8th brightest star in the sky. It shines with a magnitude of 0.45 and lies at a distance of roughly 600 light years. If we put Betelgeuse in our solar system it would be nearly as large as the orbit of Jupiter. This is a fascinating star that is a great place to start exploring Orion. Below you will find basic star chart that will assist in finding Betelgeuse and the rest of the targets we will discuss in the following weeks.
The object for the week of January 13 is the stellar nursery M42 also named The Great Orion Nebula. Before we talk about this nebula there is another feature of Orion we should discuss. Doing so will give us a better appreciation for Orion and what is taking place in that part of the sky. Orion is in a part of the Milky Way known as the Orion Spur. This is the same part of the Milky Way that the Sun is part of. In the winter months we are looking at some our nearest neighbors in the galaxy. Also of interest is that most of Orion is immersed in a molecular cloud of hydrogen, dust and a mixed bag of other elements. This cloud is known as the Orion Molecular Complex and it is an area in the Milky Way that acts as a cauldron for star formation. Most of the brightest stars in Orion are the products of this giant molecular cloud. Most of these bright stars have formed over the last 12 million years. The brightest of these stars are O and B class stars and when they exhibit the same proper motion they are called an OB Association. Collectively Orion has what is called the Orion OB1 association. This is made up of four distinct age groups known as OB1a, OB1b, OB1c and OB1d. The oldest of these groups is OB1a at 12 million years old and the Newest is OB1d at an age of roughly 30,000 years old. There is some data that suggests the youngest members of OB1d are only 10,000 years old. These are stars that fit inside the recent history of humankind. The oldest identified culture in North American is the Clovis culture. They were an early nomadic culture that existed roughly 10,000 to 13,000 years ago. It is likely within this cultures existence that the youngest stars in the OB1d association first started to shine.
This brings us to our object of the week M42. The stars in the OB1d association all came from the bright emission nebula M42. This is currently the most active star forming region in the Orion Molecular Complex and it is still actively producing stars. To find M42 look for what appears to be three stars in a line perpendicular to and below the belt of Orion. Scanning the central of these stars with a pair of binoculars you will quickly see that there are more than just three bright stars. M42 will stand out as a large dim patch of greyish light with what looks like a dark finger poking into the object. Sadly the human eye is not sensitive enough to perceive the color of this nebula as it has a bright pinkish color. The color seen in emission nebulae is caused by the young hot stars exciting the gasses in the nebula through a process called ionization.
The group of stars that is mainly responsible for the ionization of M42 can be seen through a small telescope and are known as the Trapezium Cluster. They will appear to be four stars arranged in a trapezoid shaped and are the brightest components of the OB1d association discussed above. Larger telescopes will be able to reveal a few more stars that are members of this small cluster of stars. The Trapezium Cluster is so young that many of its members are either still shrouded in the gasses and dust of M42 or are still actively forming. Many these stars are only visible using telescopes like the Hubble or others that have the ability to observe in the infrared wavelength of light.
If you have ever wondered about how stars form, M42 and the rest of Orion is the best example of this process we can see in the northern hemisphere. The rest of the objects we will cover this month will all be members of the Orion Molecular Complex. Some will be more of the young star clusters that have formed over the last 12 million years and one will be a cloud of dust and gas that is visible due to reflected star light. Orion is a favorite constellation for many. He has huge cultural significance, he is bright and easy to find and lastly he will keep even the most avid stargazer busy due to the numerous deep sky objects scattered through the constellation. Below you will find link to a star chart for Orion and a link to the Hubble Space Telescope website.
Our next Star Party will be held on Friday, February 7, 2014, from dusk until 10 p.m.
Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions. Telescope viewing begins at 8:00 p.m. Regardless of the weather on February 7, join us indoors in our planetarium theater for “The Sky Tonight”. Showtime is at 7 p.m. There will also be two Laserium shows this night at 8:30 p.m. and 10:00 p.m. Information for laser shows can be found at http://www.slsc.org/laserium
This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.
The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge. For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org