The Monthly Newsletter of the Bays Mountain Astronomy Club · 2018-09-27 · the myths and fun...

The Monthly Newsletter of the

BaysMountain AstronomyClub

Edited by Adam Thanz M o re o n t h i s i m a g e .

S e e F N 1

October 2018

Chapter 1

Cosmic Reflections

W i l l i a m Tro x e l - B M A C C h a i r

M o re o n t h i s i m a g e .

S e e F N 2

Greetings fellow BMACers

September went by so quickly, however that puts us at October which is a very busy month for our club. More on October’s activities later. I always like to recap the month in case you were not able to come out. I wanted to thank Adam and Jason for hosting the club to use the planetarium theater for our meeting last month.

Robin Byrne was the speaker, she always does a wonderful job. This program was out of the galaxy! Her presentation was about the history and astronomy of the “Pic du Midi Observatory” in the French Pyrenees. She shared some of her pictures she took while visiting there. While she discussed the history of the observatory, it was like all history. It showcased the struggles that were endured because of the dream of the pioneers. She also shared some of the research the observatory has done and is continuing to do in the quest to understand our Solar System, our galaxy and the Universe. Saying that some of the pictures were jaw dropping goes without saying. Maybe someday I will get to visit. Until then I can dream, which was made a little easier

seeing Robin’s presentation. Thank you again, Robin, for sharing your experience with the club members.

Following Robin’s presentation, Adam shared some of the panoramas he had captured while up at the observatory during their visit. They also just added to the jaw dropping experience that was displayed in photographic presentation. Thanks goes out to Adam for sharing his photographic journey. I can only image what it felt like to be there to experience it live.

I want to extend a welcome our new club members, James & Pam Sherwood of Kingsport, TN. We also welcomed some visitors which is always wonderful. Hopefully they will come back again. Please introduce yourself to our new members and any visitors that you may meet at the meetings.

Our business meeting covered a few things. Upcoming events which are starting with the October monthly meeting, I will remind you at the end of this article again. I shared a couple of ideas that I have been developing. One was having an annual observational contest for members which did not seem to have much support. The other was an annual BMAC Outreach

William Troxel

Cosmic Reflections

Bays Mountain Astronomy Club Newsletter October 2018 3


S e e F N 3

4 Bays Mountain Astronomy Club Newsletter October 2018

Image from Stellarium

Annotation by Adam Thanz

Ambassador Award. This got better support from the members. I am working on the details and will share them as soon as they are complete. Adam then shared an update on StarFest which of course is the big event coming up for the club. We closed our meeting with the social in the lobby of the Nature Center.

This month, Jason and I will again start sharing parts of the monthly constellation for your reading enjoyment. I will talk about the myths and fun facts about the monthly constellation, Jason will share the technical and scientific information. Please continue to the next section to read his article also. Pegasus is the winner for October. You all know Pegasus is the “Flying Horse” that was the son of Poseidon and his mother was the dreadful monster, MEDUSA. She had snakes for hair and hated everyone, even her son Pegasus.

Pegasus did not mind that he was born a horse. He liked the fact that he had power and speed that being a horse gave him. The problem was that people were always trying to catch him. At first he liked it because it was a fun game for him. He was a horse that could fly. Everyone could see the value of this gift. Pegasus was safe but very lonely, he could not live with his father under the water because he did not have the ability to breath there. He did not want to live with his mother because she hated him. All the other horses shied away. He belonged nowhere it seemed, so he kept himself busy saving others, especially Greek soldiers wounded in battles. However it was not the same thing as having

a family or friends to do things with. Zeus, the King of the Gods noticed that Pegasus was very depressed and befriended him. Zeus brought him to live at Mount Olympus. Very soon the people would see Pegasus flying through the stars. The friendship between Zeus and Pegasus grow and made them both very happy.

Then one day when Perseus, another demigod, killed his mother, Medusa. He was afraid that Pegasus would be very upset and therefore make Zeus mad at him. The truth was that Pegasus was so happy that his mean mother was dead. From that day forward Pegasus and Perseus were good friends. Legend tells that they were not the best of friends as he and Zeus, but reminded very good friends all their days. After many years, Zeus granted him a place in the MilkyWay for his good deeds where all the peoples of the Earth could be reminded of him forever.1

Let’s now move right into our continued communication about our home galaxy, the Milky Way. This month we start our conversation with fact number 4: “It’s really dusty and gassy.”2

While logical, this has caused me some confusion. Our galaxy, being as old as it is or what we understand about the age of the Milky Way, would seem to have time for the removal of all the dust and gases that is not needed in the formation of the planets. I knew that space dust and gas is the star and planet formation material. Does this mean that our galaxy is still forming stars and planets to this day?



Our Solar system is in the Orion-Cygnus arm, which is the

orange arm of the drawing.3

While the article does not seem to address this question it does explain that what they are referring to the 10 to 15% which is the dust and gas. The rest, the article writes, is made up of stars. Ten to fifteen precent is not much of the total galaxy which makes this fact misleading if taken only at the statement itself. It will be interesting to see how this changes as we learn more about our galaxy.

Fact number #5; “It was made from other Galaxies.”2

One side of my mind thinks that is really an interesting thing, giving way to theories that right here in our very own galaxy is bits and pieces of the entire Universe. This will answer the many questions we have about how things got started in the first place. Then comes the other side of my mind that is yelling “NO, NO, NO,” it is not nice and interesting at all. The thought then comes: this means that all other galaxies are being torn apart to form our galaxy, there is nothing nice and easy about that concept. IT IS VERY VIOLENT! Imagine the amount of energy it takes to tear something as big as a galaxy apart. In my mind the only thing I can relate to this would be the strongest hurricane multiplied by 1 million. I have been in Florida and seen what a small hurricane can do so to have something 1 million times stronger, honestly I can’t even imagine. Maybe this is one of those things that needs to be seen with my own eyes to believe.

Fact number # 6; “Every Picture of the Milky Way you’ve seen isn’t it.”2

I knew it! I have always had an issue with this picture and I never knew who to ask or why I had a problem accepting this. I consider myself to be well-read person. Come on, if someone had gotten a true picture of our home galaxy the picture would be all over the world in a second. That would overshadow everything. Some of my friends ask me “what does it matter what our home galaxy looks like?” I do not know the answer. A part of me feels like it is in the part of learning for the sake of learning, expanding our mind. What will we get from the knowledge that will make us better. Right now I just feel that it would help us understand what our galaxy is.

For now I enjoy looking into the night sky and seeing the arm of our galaxy. Having read this article I feel like I know something about this path across the night sky. I may never understand it completely. For me everything I learn about it makes it that more interesting to look at. Hopefully it will give you something to think about, or at least look at a photograph.

October’s meeting, of course, will start at 6 p.m. due to the cleanup of the two observatories at the Park. I really want to strongly encourage each of you to come out and help with the cleanup. Adam has many times said, and he is right, “the more people we have, the faster we can get the job completed.”

The reason we take this time and do this job every year has a few purposes. We all know that we will have guests coming into the observatories because of StarFest 2018, but we will also be


hosting the public every Saturday night during our Fall StarWatch event. Just as a reminder, this free event will be every Saturday evening starting in October and continuing thru the last Saturday of November, starting at dusk. This meeting, will if we can get a break with the weather, will include observing after the clean up. Should the clouds roll in on us, we will go over for a show in the Planetarium.

Hope to see each of you. Until next time, clear skies…

1- https://greece.mrdonn.org/greekgods/pegasus.html

2- www.universetoday.com

3- wikipedia.org


https://greece.mrdonn.org/greekgods/pegasus.html

https://greece.mrdonn.org/greekgods/pegasus.html

http://www.universetoday.com

http://www.universetoday.com

Chapter 2

Celestial Happenings

J a s o n D o r f m a n


S e e F N 5

October is here! And that means slightly cooler weather and changing scenery, both of which make this one of my favorite times of the year. It also means that StarFest is about to occur! StarFest is our annual gathering of fellow stargazers and, this year, will be happening from the 12th through the 14th. We'll have a waxing crescent Moon at that time, so for those who enjoy some late night observing you'll have some dark skies once it sets.

Over the last few months, we've enjoyed being able to view many of the naked-eye planets in our early evening skies. But, with October, we'll begin to see them disappear one by one over the next few months, starting with Venus. Don't worry, though, there's still plenty else to see. This month, there is the potential for two decent meteor showers and you'll be able to see the cometary source for one of them.

PlanetsThis month, the two inner planets, Mercury and Venus, will be hovering close to the horizon as the Sun goes down. Venus has been very prominent in the evening sky for the last several months but is now getting low in the sky and will disappear into

the twilight glow after the first week of October. Though Venus begins the month about 30° east of the Sun, it remains quite low due to the shallow angle of the ecliptic at this time of year and, also, the planet is currently about 5° below the ecliptic. On the 1st, Venus will be about 4° above the horizon in the west-southwest a half hour after sunset. Its magnitude will be -4.7, so you should see it with a clear view to the horizon despite the twilight sky. If you glimpse it through a telescope, you'll see a 47" diameter disk in a thin, crescent phase. Over the first week, Venus will dip into the setting sunlight. On the 26th, it will pass between the Sun and Earth and transition to our morning skies early next month.

Mercury crossed the far side of the Sun on the 20th of September making its way into our evening skies. The low angle of the ecliptic, however, will keep it hidden from view until the last week of October. And, even then, it will be a difficult target. Break out your binoculars on the 27th when Mercury will be directly below bright Jupiter. A half hour after sunset, Jupiter will be shining at magnitude -1.7 about 7° above the horizon in the west-southwest. Once you find it, look about 3° below for fainter

Jason Dorfman

Celestial Happenings



S e e F N 3

Mercury at magnitude -0.2. Mercury will remain at the same altitude for the rest of the month at that same time as Jupiter moves lower and to the right of Mercury.

At the beginning of the month, Jupiter will be a much easier find. Look for Jupiter on the 1st about 10° above the southwest horizon an hour after sunset. At magnitude -1.8, you should have no problem discerning it from the receding twilight. Each week, Jupiter will lose about 3° of altitude so, earlier in the month will be your best opportunity for observations with a telescope.

Next, turn a little towards the south and look a bit higher for +0.5 magnitude Saturn. Saturn will be about 30° high just west of south as the sky begins to darken. By the end of the month, it will have moved towards the southwest and dropped slightly in altitude. Saturn remains amongst the backdrop of our Milky Way galaxy in Sagittarius. Telescopes provide the most spectacular views. At mid-month, the disk of Saturn spans 16". The ring plane spans 37" and remains very open to us at a tilt of 27°.

Outshining Saturn about 40° eastward is Mars. Though opposition has passed, you can still achieve some good views of the "Red Planet," if only the weather would cooperate! Plus, now that the dust storm has subsided, you might still be able to identify some surface features near the start of the month. As October progresses, the magnitude of Mars will lessen from -1.3 to -0.6 and the diameter of the disk will shrink from 16" to 12". Obtaining the best views will be when Mars is highest in the

south, which will be about 9:30 p.m. on the 1st with Mars about 30° high and an hour earlier by the 31st with Mars ascending a bit higher to 36°. Mars is currently located in the western side of Capricornus and will move through to the eastern side of the constellation over the course of the month.

One of the fainter planetary highlights for the month is Uranus. It will reach opposition on the 23rd so it will be observable throughout the night. It shines at magnitude +5.7 and will be about 65° high around 1 a.m., the highest that it has been at opposition since February 1962. The high altitude means that you should be able to enjoy some wonderful views of this ice giant due to less interference from the Earth's atmosphere. However, there will be a nearly full Moon at opposition about 8° to the lower right of the planet. But, since this outer world moves slowly, those wonderful views can still be obtained throughout the entire month.

LunaFull Moon occurs on the 24th of the month, though a nearly full Moon will appear low in the east after sunset for a few days around this date. Due to the shallow angle of the ecliptic, the Moon will rise 30 minutes later each night compared to an average of 50 minutes. This has been called a Hunter's Moon.

In the early evening hours of the 11th, a thin sliver of a crescent Moon will be about 3° to the upper right of Jupiter. A few days later, on the 14th, a more easily seen crescent will be within 2° to


the right of Saturn around 10 p.m. Over the 17th and 18th, a first quarter Moon will cross in front of Mars.

Meteor ShowersOctober holds the potential for two smaller meteor showers. The Orionids is the more prominent event for the month and will peak during the early morning hours of the 21st. There will be a waxing gibbous Moon then that will set about 4 a.m., leaving a couple of hours for darker observations. The Orionids normally have a rate of about 10-20 an hour.

However, the normally minor Draconids, which peaks on the night of the 8th/9th, has the potential to upstage the Orionids this year because its parent comet - 21P/Giacobini-Zinner - made its close approach to the Sun last month. Outbursts have been observed following the comet's return previously.

The source comet for the Draconids can be observed this month in the predawn skies moving from Monoceros into Canis Major towards Puppis. It will pass within 0.5° of M50 on the 7th/8th and about midway between Sirius and alpha Mon on the 13th. The comet is expected to be about 8th magnitude and should have a nice gas tail about 1° long due to the recent close approach to the Sun. How often can you observe a meteor shower and the comet that caused it all in the same evening?

That is all for this month.

Clear Skies and Happy Observing!12 Bays Mountain Astronomy Club Newsletter October 2018

Chapter 3

TheQueenSpeaks

R o b i n B y r n e

This month, we honor another female trailblazer. Liu Yang was born in Zhengzhou, Henan in China on October 6, 1978. To be clear, because this is a Chinese name, Liu is the surname, and Yang would be the equivalent to a first name. Yang’s early career choices didn’t quite fit her ultimate occupation, with dreams of being a lawyer like the ones she saw on television shows, or a bus conductor so she could ride the bus daily.

What decided Liu’s career was a visit to her school by representatives of the People’s Liberation Army (PLA). Now she knew what she would become - a pilot. After her public school work was complete in 1997, Liu attended the PLA Air Force Aviation University in Changchun. During her time in the PLA, Liu qualified to become a pilot, training to fly transport planes. During one of her flights, her jet hit a flock of pigeons, which disabled one of the engines. Despite the potentially fatal damage to her plane, Liu remained calm and managed to land safely. Liu rose through the ranks to become a major in the PLA Air Force, and has flown over 1,600 hours. She was eventually named the Deputy Head of a flying unit. Proud of her career, on China’s

equivalent to Skype, called Tencent QQ, Liu goes by the handle “Little Flying Knight.”

In May, 2010, Liu was approached with the offer of being a candidate for the taikonaut (Chinese astronaut) corps. After being accepted as a candidate, she trained for two years before being selected as a taikonaut. Asked if being a woman affected how she was treated, Liu said, "From day one I have been told I am no different from the male astronauts.” While in training, Liu’s name was placed on the list of finalists for the Shenzhou 9 mission.

On March 12, 2012, the official crew for Shenzhou 9 was announced. Jing Haipeng (commander), Liu Wang (pilot, and no relation to Liu Yang), and Liu Yang (mission specialist) - becoming China’s first woman in space. Shenzhou 9 was the fourth manned flight in the Chinese program. Launch occurred on June 16, 2012, exactly 49 years after Valentina Tereshkova became the first woman in space. On June 18, it became the first manned spacecraft to dock with the Chinese space station, Tiangong 1. The docking was remotely controlled by the ground crew. After pressurizing the space station, Jing was able to enter.

Robin Byrne

Happy Birthday Liu Yang



S e e F N 3


R. The Shenzhou 9 mission patch.

L. Liu Yang while visiting the Chinese University of Hong

Kong on August 12, 2012.

Images from Wikipedia.

Later in the mission, they undocked from the station, and Liu Wang performed the first manual docking. Liu Yang performed space medicine experiments throughout the flight. After 13 days in space, they landed by parachute in the Inner Mongolia Autonomous Region.

With this flight, China became the third country, after the Soviet Union and the United States, to send a woman into space using their own space craft. As a result of the flight, Liu found herself repeatedly being interviewed about being the first Chinese woman in space. The tone of the questions, and her answers, definitely reflect a different attitude towards women compared to the United States, with ideas more similar to our nation in the 1960’s rather than the 2010’s. When asked about the advantages of having a crew with both men and women, Liu replied, “I think both female and male astronauts have their own advantages in the course of the exploration of the Universe. For example, men are superior in strength and endurance whereas women are more resilient, soft and approachable. Working in a confined space requires a high level of affinity and integration within a team. Thus, feminine seriousness and delicacy are very helpful in conducting experiments in space.” Other questions were about how she balanced work and family, with Liu admitting to feeling guilty over not spending much time with her husband during her training.

Since her flight, Liu has spoken at public events about her flight, while continuing to train in the taikonaut corps. She and her husband did have a child in 2015, but no other information was released, not even the gender. In her spare time, Liu is described as an avid reader, and a lover of cooking, especially “cola chicken wings.”

Advances for women in typically male-dominated fields always come slowly and with difficulty. Liu Yang has blazed the trail for other female taikonauts in China. Hopefully, with these advances in careers, we will also see advances in attitudes toward women. Meanwhile, let us all wish Liu Yang a very happy 40th birthday!

References:

Liu Yang (astronaut) Wikipedia

https://en.wikipedia.org/wiki/Liu_Yang_%28astronaut%29

Astronaut Liu Yang: Balance Between Family and Career helps Me Fly High by Jane Wang, Women of China

http://www.womenofchina.cn/womenofchina/html1/people/others/1707/556-1.htm

China’s First Woman in Space: Q&A with Astronaut Liu Yang by Rob Coppinger, space.com

https://www.space.com/17887-china-first-female-astronaut-liu-yang-interview.html




http://www.womenofchina.cn/womenofchina/html1/people/others/1707/556-1.htmChina











Liu Yang in the Chinese Space

Station.

Image from Wikipedia.

Profile of Liu Yang, China’s first woman astronaut, BBC News

https://www.bbc.com/news/science-environment-18471236

Shenzhou 9 Wikipedia

https://en.wikipedia.org/wiki/Shenzhou_9

Liu Yang: China’s first female astronaut, PHYS.org

https://phys.org/news/2012-06-liu-yang-china-female-astronaut.html






Chapter 4

Space Place


S e e F N 6

Feeling like you missed out on planning a last vacation of summer? Don’t worry—you can still take a late summertime road trip along the Milky Way!

The waning days of summer are upon us, and that means the Sun is setting earlier now. These earlier sunsets reveal a starry sky bisected by the Milky Way. Want to see this view of our home galaxy? Head out to your favorite dark sky getaway or to the darkest city park or urban open space you can find.

While you’re out there waiting for a peek at the Milky Way, you’ll also have a great view of the planets in our Solar System. Keep an eye out right after sunset and you can catch a look at Venus. If you have binoculars or a telescope, you’ll see Venus’s phase change dramatically during September—from nearly half phase to a larger, thinner crescent.

Jupiter, Saturn and reddish Mars are next in the sky, as they continue their brilliant appearances this month. To see them, look southwest after sunset. If you’re in a dark sky and you look above and below Saturn, you can’t miss the summer Milky Way spanning the sky from southwest to northeast.

You can also use the summer constellations to help you trace a path across the Milky Way. For example, there’s Sagittarius, where stars and some brighter clumps appear as steam from a teapot. Then there is Aquila, where the Eagle’s bright Star Altair combined with Cygnus’s Deneb and Lyra’s Vega mark what’s called the “Summer Triangle.” The familiar W-shaped constellation Cassiopeia completes the constellation trail through the summer Milky Way. Binoculars will reveal double stars, clusters and nebulae all along the Milky Way.

Between Sept. 12 and 20, watch the Moon pass from near Venus, above Jupiter, to the left of Saturn and finally above Mars!

This month, both Neptune and brighter Uranus can also be spotted with some help from a telescope. To see them, look in the southeastern sky at 1 a.m. or later. If you stay awake, you can also find Mercury just above Earth’s eastern horizon shortly before sunrise. Use the Moon as a guide on Sept. 7 and 8.

Although there are no major meteor showers in September, cometary dust appears in another late summer sight, the morning zodiacal light. Zodiacal light looks like a cone of soft light in the night sky. It is produced when sunlight is scattered by dust in our Solar System. Try looking for it in the east right before

Jane Houston Jones and Jessica Stoller-Conrad

A Trip Through the Milky Way



S e e F N 3



S e e F N 8

sunrise on the moonless mornings of Sept. 8 through Sept 23.

You can catch up on all of NASA’s current—and future—missions at www.nasa.gov

This article is distributed by NASA Space Place. With articles, activities and games NASA Space Place encourages everyone to get excited about science and technology. Visit spaceplace.nasa.gov to explore space and Earth science!


http://www.nasa.gov

http://www.nasa.gov

Chapter 5

BMAC

Calendar

and more


S e e F N 7

BMAC Calendar and more



S e e F N 3

Date Time Location Notes

B M A C M e e t i n g sB M A C M e e t i n g sB M A C M e e t i n g sB M A C M e e t i n g s

Friday, October 5, 2018 6 p.m. ObservatoriesProgram: Observatory Cleaning & Observing to Follow. If poor weather, we will see a planetarium show instead.;

Please show up at the observatory by 6 p.m. and bring cleaning supplies, vacuum, broom, rags, etc. Many hands make short work!; Free.

Friday, November 2, 2018 7 p.m.Nature Center

Discovery TheaterProgram: Program TBA; Free.

Friday, December 7, 2018 7 p.m.Nature Center

Discovery TheaterProgram: “Binoculars for Astronomy.” Dr. Greg Love, ETSU Physics and Chemistry Instructor and BMAC

member, will speak about how to use common, everyday binoculars to enjoy the night sky.; Free.

S u n W a t c hS u n W a t c hS u n W a t c hS u n W a t c h

Every Saturday & SundayMarch - October

3-3:30 p.m. if clear

At the dam View the Sun safely with a white-light view if clear.; Free.

S t a r W a t c hS t a r W a t c hS t a r W a t c hS t a r W a t c h

Oct. 6, 13, 2018 7:30 p.m.

ObservatoryView the night sky with large telescopes. If poor weather, an alternate live tour of the night sky will be held in the

planetarium theater.; Free.Oct. 20, 27, Nov. 3, 2018 7:00 p.m. Observatory

View the night sky with large telescopes. If poor weather, an alternate live tour of the night sky will be held in the planetarium theater.; Free.

Nov. 10, 17, 24, 2018 6:00 p.m.

ObservatoryView the night sky with large telescopes. If poor weather, an alternate live tour of the night sky will be held in the

planetarium theater.; Free.

Bays Mountain Astronomy Club

853 Bays Mountain Park Road

Kingsport, TN 37650

1 (423) 229-9447

www.BaysMountain.com

[email protected]

Annual Dues:

Dues are supplemented by the Bays Mountain Park Association and volunteerism by the club. As such, our dues can be kept at a very low cost.

$16 /person/year

$6 /additional family member

Note: if you are a Park Association member (which incurs an additional fee), then a 50% reduction in BMAC dues are applied.

The club’s website can be found here:

https://www.baysmountain.com/astronomy/astronomy-club/#newsletters

Regular Contributors:William Troxel

William is the current chair of the club. He enjoys everything to do with astronomy,

including sharing this exciting and interesting hobby with anyone that will

listen! He has been a member since 2010.

Robin Byrne

Robin has been writing the science history column since 1992 and was chair in 1997.

She is an Associate Professor of Astronomy & Physics at Northeast State

Community College (NSCC).

Jason Dorfman

Jason works as a planetarium creative and technical genius at Bays Mountain Park.

He has been a member since 2006.

Adam Thanz

Adam has been the Editor for all but a number of months since 1992. He is the

Planetarium Director at Bays Mountain Park as well as an astronomy adjunct for

NSCC.


http://www.BaysMountain.com

http://www.BaysMountain.com

mailto:[email protected]?subject=

mailto:[email protected]?subject=





Footnotes:1. The Rite of SpringOf the countless equinoxes Saturn has seen since the birth of the solar system, this one, captured here in a mosaic of light and dark, is the first witnessed up close by an emissary from Earth … none other than our faithful robotic explorer, Cassini.Seen from our planet, the view of Saturn’s rings during equinox is extremely foreshortened and limited. But in orbit around Saturn, Cassini had no such problems. From 20 degrees above the ring plane, Cassini’s wide angle camera shot 75 exposures in succession for this mosaic showing Saturn, its rings, and a few of its moons a day and a half after exact Saturn equinox, when the sun’s disk was exactly overhead at the planet’s equator.The novel illumination geometry that accompanies equinox lowers the sun’s angle to the ring plane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and to cast shadows across the rings. These scenes are possible only during the few months before and after Saturn’s equinox which occurs only once in about 15 Earth years. Before and after equinox, Cassini’s cameras have spotted not only the predictable shadows of some of Saturn’s moons (see PIA11657), but also the shadows of newly revealed vertical structures in the rings themselves (see PIA11665).Also at equinox, the shadows of the planet’s expansive rings are compressed into a single, narrow band cast onto the planet as seen in this mosaic. (For an earlier view of the rings’ wide shadows draped high on the northern hemisphere, see PIA09793.)The images comprising the mosaic, taken over about eight hours, were extensively processed before being joined together. First, each was re-projected into the same viewing geometry and then digitally processed to make the image “joints” seamless and to remove lens flares, radially extended bright artifacts resulting from light being scattered within the camera optics.At this time so close to equinox, illumination of the rings by sunlight reflected off the planet vastly dominates any meager sunlight falling on the rings. Hence, the half of the rings on the left illuminated by planetshine is, before processing, much brighter than the half of the rings on the right. On the right, it is only the vertically extended parts of the rings that catch any substantial sunlight.With no enhancement, the rings would be essentially invisible in this mosaic. To improve their visibility, the dark (right) half of the rings has been brightened relative to the brighter (left) half by a factor of three, and then the whole ring system has been brightened by a factor of 20 relative to the planet. So the dark half of the rings is 60 times brighter, and the bright half 20 times brighter, than they would have appeared if the entire system, planet included, could have been captured in a single image.The moon Janus (179 kilometers, 111 miles across) is on the lower left of this image. Epimetheus (113 kilometers, 70 miles across) appears near the middle bottom. Pandora (81 kilometers, 50

miles across) orbits outside the rings on the right of the image. The small moon Atlas (30 kilometers, 19 miles across) orbits inside the thin F ring on the right of the image. The brightnesses of all the moons, relative to the planet, have been enhanced between 30 and 60 times to make them more easily visible. Other bright specks are background stars. Spokes -- ghostly radial markings on the B ring -- are visible on the right of the image.This view looks toward the northern side of the rings from about 20 degrees above the ring plane.The images were taken on Aug. 12, 2009, beginning about 1.25 days after exact equinox, using the red, green and blue spectral filters of the wide angle camera and were combined to create this natural color view. The images were obtained at a distance of approximately 847,000 kilometers (526,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 74 degrees. Image scale is 50 kilometers (31 miles) per pixel.The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/. The Cassini imaging team homepage is at http://ciclops.org.Image Credit: NASA/JPL/Space Science Institute

2. Leo RisingA sky filled with stars and a thin veil of clouds.Image by Adam Thanz

3. The Cat's Eye Nebula, one of the first planetary nebulae discovered, also has one of the most complex forms known to this kind of nebula. Eleven rings, or shells, of gas make up the Cat's Eye.Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA)Acknowledgment: R. Corradi (Isaac Newton Group of Telescopes, Spain) and Z. Tsvetanov (NASA)

4. Jupiter & GanymedeNASA's Hubble Space Telescope has caught Jupiter's moon Ganymede playing a game of "peek-a-boo." In this crisp Hubble image, Ganymede is shown just before it ducks behind the giant planet.

Footnotes



S e e F N 3

http://saturn.jpl.nasa.gov

http://saturn.jpl.nasa.gov

http://ciclops.org

http://ciclops.org

Ganymede completes an orbit around Jupiter every seven days. Because Ganymede's orbit is tilted nearly edge-on to Earth, it routinely can be seen passing in front of and disappearing behind its giant host, only to reemerge later.Composed of rock and ice, Ganymede is the largest moon in our solar system. It is even larger than the planet Mercury. But Ganymede looks like a dirty snowball next to Jupiter, the largest planet in our solar system. Jupiter is so big that only part of its Southern Hemisphere can be seen in this image.Hubble's view is so sharp that astronomers can see features on Ganymede's surface, most notably the white impact crater, Tros, and its system of rays, bright streaks of material blasted from the crater. Tros and its ray system are roughly the width of Arizona.The image also shows Jupiter's Great Red Spot, the large eye-shaped feature at upper left. A storm the size of two Earths, the Great Red Spot has been raging for more than 300 years. Hubble's sharp view of the gas giant planet also reveals the texture of the clouds in the Jovian atmosphere as well as various other storms and vortices.Astronomers use these images to study Jupiter's upper atmosphere. As Ganymede passes behind the giant planet, it reflects sunlight, which then passes through Jupiter's atmosphere. Imprinted on that light is information about the gas giant's atmosphere, which yields clues about the properties of Jupiter's high-altitude haze above the cloud tops.This color image was made from three images taken on April 9, 2007, with the Wide Field Planetary Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to natural colors.Credit: NASA, ESA, and E. Karkoschka (University of Arizona)

5. 47 TucanaeIn the first attempt to systematically search for "extrasolar" planets far beyond our local stellar neighborhood, astronomers probed the heart of a distant globular star cluster and were surprised to come up with a score of "zero".To the fascination and puzzlement of planet-searching astronomers, the results offer a sobering counterpoint to the flurry of planet discoveries announced over the previous months."This could be the first tantalizing evidence that conditions for planet formation and evolution may be fundamentally different elsewhere in the galaxy," says Mario Livio of the Space Telescope Science Institute (STScI) in Baltimore, MD.The bold and innovative observation pushed NASA Hubble Space Telescope's capabilities to its limits, simultaneously scanning for small changes in the light from 35,000 stars in the globular star cluster 47 Tucanae, located 15,000 light-years (4 kiloparsecs) away in the southern constellation Tucana.Hubble researchers caution that the finding must be tempered by the fact that some astronomers always considered the ancient globular cluster an unlikely abode for planets for a variety of reasons. Specifically, the cluster has a deficiency of heavier elements that may be needed for building planets. If this is the case, then planets may have formed later in the universe's evolution, when stars were richer in heavier elements. Correspondingly, life as we know it may have appeared later rather than sooner in the universe.Another caveat is that Hubble searched for a specific type of planet called a "hot Jupiter," which is considered an oddball among some planet experts. The results do not rule out the possibility that 47 Tucanae could contain normal solar systems like ours, which Hubble could not have detected. But even if that's the case, the "null" result implies there is still something fundamentally different between the way planets are made in our own neighborhood and how they are made in the cluster.

Hubble couldn't directly view the planets, but instead employed a powerful search technique where the telescope measures the slight dimming of a star due to the passage of a planet in front of it, an event called a transit. The planet would have to be a bit larger than Jupiter to block enough light — about one percent — to be measurable by Hubble; Earth-like planets are too small.However, an outside observer would have to watch our Sun for as long as 12 years before ever having a chance of seeing Jupiter briefly transit the Sun's face. The Hubble observation was capable of only catching those planetary transits that happen every few days. This would happen if the planet were in an orbit less than 1/20 Earth's distance from the Sun, placing it even closer to the star than the scorched planet Mercury — hence the name "hot Jupiter."Why expect to find such a weird planet in the first place?Based on radial-velocity surveys from ground-based telescopes, which measure the slight wobble in a star due to the small tug of an unseen companion, astronomers have found nine hot Jupiters in our local stellar neighborhood. Statistically this means one percent of all stars should have such planets. It's estimated that the orbits of 10 percent of these planets are tilted edge-on to Earth and so transit the face of their star.In 1999, the first observation of a transiting planet was made by ground-based telescopes. The planet, with a 3.5-day period, had previously been detected by radial-velocity surveys, but this was a unique, independent confirmation. In a separate program to study a planet in these revealing circumstances, Ron Gilliland (STScI) and lead investigator Tim Brown (National Center for Atmospheric Research, Boulder, CO) demonstrated Hubble's exquisite ability to do precise photometry — the measurement of brightness and brightness changes in a star's light — by also looking at the planet. The Hubble data were so good they could look for evidence of rings or Earth-sized moons, if they existed.But to discover new planets by transits, Gilliland had to crowd a lot of stars into Hubble's narrow field of view. The ideal target was the magnificent southern globular star cluster 47 Tucanae, one of the closest clusters to Earth. Within a single Hubble picture Gilliland could observe 35,000 stars at once. Like making a time-lapse movie, he had to take sequential snapshots of the cluster, looking for a telltale dimming of a star and recording any light curve that would be the true signature of a planet.Based on statistics from a sampling of planets in our local stellar neighborhood, Gilliland and his co-investigators reasoned that 1 out of 1,000 stars in the globular cluster should have planets that transit once every few days. They predicted that Hubble should discover 17 hot Jupiter-class planets.To catch a planet in a several-day orbit, Gilliland had Hubble's "eagle eye" trained on the cluster for eight consecutive days. The result was the most data-intensive observation ever done by Hubble. STScI archived over 1,300 exposures during the observation. Gilliland and Brown sifted through the results and came up with 100 variable stars, some of them eclipsing binaries where the companion is a star and not a planet. But none of them had the characteristic light curve that would be the signature of an extrasolar planet.There are a variety of reasons the globular cluster environment may inhibit planet formation. 47 Tucanae is old and so is deficient in the heavier elements, which were formed later in the universe through the nucleosynthesis of heavier elements in the cores of first-generation stars. Planet surveys show that within 100 light-years of the Sun, heavy-element-rich stars are far more likely to harbor a hot Jupiter than heavy-element-poor stars. However, this is a chicken and egg puzzle because some theoreticians say that the heavy-element composition of a star may be enhanced after if it makes Jupiter-like planets and then swallows them as the planet orbit spirals into the star.The stars are so tightly compacted in the core of the cluster – being separated by 1/100th the distance between our Sun and the next nearest star — that gravitational tidal effects may strip nascent planets from their parent stars. Also, the high stellar density could disturb the subsequent migration of the planet inward, which parks the hot Jupiters close to the star.


Another possibility is that a torrent of ultraviolet light from the earliest and biggest stars, which formed in the cluster billions of years ago may have boiled away fragile embryonic dust disks out of which planets would have formed.These results will be published in The Astrophysical Journal Letters in December. Follow-up observations are needed to determine whether it is the initial conditions associated with planet birth or subsequent influences on evolution in this heavy-element-poor, crowded environment that led to an absence of planets.Credits for Hubble image: NASA and Ron Gilliland (Space Telescope Science Institute)

6. Space Place is a fantastic source of scientific educational materials for children of all ages. Visit them at:http://spaceplace.nasa.gov

7. NGC 3982Though the universe is chock full of spiral-shaped galaxies, no two look exactly the same. This face-on spiral galaxy, called NGC 3982, is striking for its rich tapestry of star birth, along with its winding arms. The arms are lined with pink star-forming regions of glowing hydrogen, newborn blue star clusters, and obscuring dust lanes that provide the raw material for future generations of stars. The bright nucleus is home to an older population of stars, which grow ever more densely packed toward the center.NGC 3982 is located about 68 million light-years away in the constellation Ursa Major. The galaxy spans about 30,000 light-years, one-third of the size of our Milky Way galaxy. This color image is composed of exposures taken by the Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2), the Advanced Camera for Surveys (ACS), and the Wide Field Camera 3 (WFC3). The observations were taken between March 2000 and October 2009. The rich color range comes from the fact that the galaxy was photographed invisible and near-infrared light. Also used was a filter that isolates hydrogen emission that emanates from bright star-forming regions dotting the spiral arms.Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)Acknowledgment: A. Riess (STScI)

8. This illustration shows how the summer constellations trace a path across the Milky Way. To get the best views, head out to the darkest sky you can find. Credit: NASA/JPL-Caltech


http://spaceplace.nasa.gov

http://spaceplace.nasa.gov

The Monthly Newsletter of the Bays Mountain Astronomy Club · 2018-09-27 · the myths and fun...

Documents

Transcript of The Monthly Newsletter of the Bays Mountain Astronomy Club · 2018-09-27 · the myths and fun...