Surf's Up! Astronomers Ride Stellar Waves

This week, first results from the Kepler mission are coming out in waves from the meeting of the American Astronomical Society (AAS) in Washington, DC. Carried along on those waves are papers on waves in stars. I’m referring to a branch of astronomy you’ll be hearing more about as Kepler and other missions begin to reveal the interior structures of stars- asteroseismology. So, what is asteroseismology?

Seismology is the study of earthquakes on Earth. But more importantly to our discussion, it is the study of seismic waves. Earthquakes produce different types of seismic waves that travel through different layers of rock, and providing us with a way to image structures deep within the Earth. Essentially, large earthquakes provide us with a natural sonogram to look inside the Earth, far deeper then we can tunnel or drill. Since these waves propagate all the way from one side of the planet to the other we can look all the way to the center of the Earth. This is how we know the outer core of the Earth is liquid, and the relative dimensions and densities of the other parts of the Earth’s internal and surface structure.

Copyright Nick Strobel 

www.astronomynotes.com

Asteroseismology, also known as stellar seismology, gives us the same kind of insight into the structure of stars. By studying the oscillations in pulsating stars, astronomers can peer into the very hearts of stars, one of the most difficult places to observe in the entire universe. The reason stellar interiors can be probed from oscillations is that different oscillation modes penetrate to different depths inside the star. Combining the rate, and amplitude of pulsation with other information, such as spectra, which reveals what the composition of the star is we obtain information on the internal structure of stars.

Stellar oscillation modes are divided into three categories, based on the force that drives them: acoustic, gravity, and surface-gravity wave modes. p-mode, or acoustic waves, have pressure as their force, hence the name "p-mode". These waves can tell us things about the structure and density of regions below the surface of a star. g-mode, or gravity waves, are confined to the interior of the star. f-mode, or surface gravity waves are also gravity waves, but occur at or near the outer layers of stars, so they give us information about the surface conditions of stars.

Helioseismology is the study of the propagation of wave oscillations in the Sun. Since the Sun is the closest star to us, it is much easier to study its pulsations in greater detail. By interpreting solar oscillations we can even detect sunspots on the far side of the Sun before they rotate into view. Many of our models of stellar interiors are based on information gained through studying the Sun’s oscillations. But the Sun is only one star at one point in its evolution, so to really understand stars we need to observe many more stars of different size, mass, composition and age.

That is precisely what Kepler is doing right now. The satellite is staring at a 100 square degree section of the sky between Cygnus and Lyra continuously taking data on the brightness of over 150,000 stars for the next three to five years. While Kepler’s primary mission is to discover the existence and abundance of earth-like planets around stars, all this high precision photometry will be used for other science, especially studying variable stars of all types and performing asteroseismology on stars showing solar-like oscillations.

The much-anticipated release of the first science results from the Kepler mission January 4th included numerous papers on asteroseismology and the potential for understanding stellar structure in unprecedented detail. Astronomers are riding the new wave of information on wave propagation in stars. Surf’s up!

[Originally published in Universe Today, January 5, 2010]

Extrasolar Asteroids and Ophiuchans

As promised, the full length interview with Steve Howell from NOAO and the Kepler mission is now online at Slacker Astronomy dot org.

The Kepler mission is designed to discover Earth-like planets around other stars. The Kepler space telescope will stare at a field bordering Cygnus and Lyra for three to five years, continuously monitoring over 150,000 stars for exoplanet transits. According to a recent paper from Howell and collaborators, Kepler should also be able to detect asteroids orbiting white dwarfs.

And just for fun, Steve and I talk about the long lost astrological sign Ophiuchus.

The Monthly Sky Guide a Book Review

One of the nice things about writing an astronomy blog is I get copies of astronomy books from various publishers sent to me to review. Just before Christmas I received a copy of the eighth edition of Ian Ridpath and Wil Tirion's 'The Monthly Sky Guide'.

This book is a classic beginner level guide to the night sky that includes a great introductory text on finding your way around the heavens, tips on observing the four brightest naked eye planets, a very nice guide to observing the Moon, complete with detailed lunar maps with features labeled, and star charts for each month of the year.

The attention to detail and practicality are notable. For example, the Moon maps are made large enough to show quite a bit of detail. This necessitates them being printed as roughly half a hemisphere per page. Instead of losing detail in the margins of some of the most interesting features on the lunar surface, the maps overlap quite a bit. This is a handy feature that could easily have been overlooked by less experienced or detail oriented authors or publishers.

Everyone you show the Moon to wants to know where the astronauts landed. In answer to this, the sky guide Moon maps show the locations of the landings of Apollo 11, 12, 14, 15 and 16 (remember Apollo 13 never made it to the surface, "Houston, we have a problem!")

The real meat and potatoes of the book are the monthly sky charts, depicting the stars, constellations, nebulae, star clusters and galaxies that are visible to the observer with the unaided eye, binoculars or a small telescope. Thee is also a description of the location and brightness of Venus, Mars, Jupiter and Saturn each month from 2010 to 2014, so this book will serve readers well for the next five years. Also listed are lunar and solar eclipses, and meteor showers visible for each month for the next five years.

The star maps are first quality and should make the beginner or intermediate observer anxious to go check out what can be seen each month. I've been observing the sky for nearly forty years and I find them to be a pleasure to look at and use. Wil Tirion is widely considered the leading celestial cartographer of our time. This night sky guide is just another example of why.

Featured each month are star maps and text highlighting a particular constellation or region of the sky. January features Orion and all the wonderful nebulae and clusters visible to binoculars and small telescopes. The text is well written and scientifically accurate in every aspect. I expected nothing less from the editor of the Oxford Dictionary of Astronomy and Norton's Star Atlas.

If you have a young person or friend you would like to share your love of astronomy with, get them a pair of binoculars and this book and you'll have a star gazing friend for life.

A New Year of Carnival of Space Begins!

The first Carnival of Space for 2010 is now online. You can find it over at Steve's Astro Corner.

Blogger, Stephan Tilford, is an amateur astronomer from Cincinnati who is involved in outreach and works with Boy Scouts of America. He belongs to the Cincinnati Astronomical Society and the Cincinnati Observatory Center. Steve sums up his enthusiasm like this. "I love sharing my love of the night sky with people who might have never gotten a glimpse of Jupiter or the rings of Saturn or countless other grand eye candy. I love to hear that tell tale 'Wow!' I go to at least two Star parties a year. and sometimes more if wife and funds allow."

Ya gotta love it. He put together a sweet Carnival. Check out Carnival of Space #135 at Steve's Astro Corner.

Kepler Could Discover Asteroids Around White Dwarfs

Today on the 365 Days of Astronomy Podcast, I interview Steve Howell from NOAO, about the Kepler mission. We talk a little about the mission goals, debunk some misinformation and rumors about the detectors, and discuss the potential for Kepler to detect transits of asteroids orbiting around white dwarfs.

There will be a Slacker Astronomy episode later this month featuring the entire interview, which also includes some discussion of the 13th astrological sign, Ophiuchus, along with some other silliness.

NASA spam--Update

Well, it turns out that NASA wasn't spamming me exactly. I was receiving the emails through the Slacker Astronomy notification system. People are invited to make comments and suggestions for topics through the Slacker website. Someone at the Office of Public Affairs at Goddard Space Flight Center decided to add the Slacker email address to the list of news services and blogs they send these press releases to. Doing this without asking if we wanted these notifications is essentially spamming, but the lady at Goddard was very apologetic and reasonable, and we have been removed from the list.

Hey, they're NASA. We love NASA. Stuff happens.
Although I'm sure my complaining has put me on yet another government watch list and blown whatever chance I had at going into space...ever.

Is NASA spamming me?

I recently started getting emails with satellite images of earth's surface and weather from someone at NASA. I never subscribed for this, and I don't know who this person is. How irritating. She apparently works for the Office of Public Affairs, so I will give her the benefit of doubt... for a minute.

Maybe she thought I'd be interested because I write a space science blog--I'm not. I'm really only interested in weather that affects me and my own observing. I don't have time to examine images of icebergs off the coast of Australia or storm clouds over the Indian Ocean. I have RSS feeds, my Google reader and some small programs that crawl the web for things I am likely to be interested in, BECAUSE I don't have time to read everything.

I'm hoping this is just an honest mistake, and she didn't presume to just start sending me email with large image files attached. My email rejects most of the Viagra and penis enlargement email these days. I really don't want it to have to block message from NASA!

I've called her office and emailed to see if we can clear this up. I'll let you know...

Astronomy and Fantasy Football?

I love NFL football. It's the only sport I follow anymore. I used to love baseball, but when they canceled the world series while on strike, I gave up on baseball. I mean really, they didn't even cancel the World Series for World War II, but they canceled it over money? Screw baseball.

So NFL football is the only pastime, hobby, diversion I have to take me away from astronomy 24/7. I need a distraction for my sanity, so I won't apologize for my obsession with football.

A few years ago, my son asked me to join a fantasy football league he was in with co-workers. I'd never played before, and wasn't sure what it was all about, but quickly realized that this was made for me and my OCD personality. Essentially, you draft your own team from the player pool of the NFL and then play games each week in head to head competition based on the statistical performance of the players on your team in games played each week. You can trade players with other owners and pick up players off the waiver wire, just like in the NFL.

It was the best $150.00 I ever spent. My son and I played each other in the Super Bowl that first year, and he won. We've been playing against each other ever since, and we've spent hours and hours debating football, life, and a million other things we probably wouldn't have taken the time to discuss if we didn't share this fantasy football obsession.

In September this year, we went to a Browns/Vikings game in Cleveland to see Brett Favre one more time before he retires. It was a glorious road trip. We drove to Cleveland the night before the game, had a great dinner and debated football and life over drinks to the wee hours. Then we drove to the game in the morning and enjoyed one of the most perfect, sunny, crisp days football was ever played under in a terrific stadium with rabid fans. It was a ball. Our plan is to visit all the NFL stadiums in the next decade or so. Sooner or later we'll be dragging my grandson along for an education in football fanaticism.

Through the years, my son has beaten me consistently in our head to head fantasy competitions. He has won two league championships, while until last year, I rarely even made the playoffs. Last year, I snuck into the playoffs as the last seed and went all the way from 6th spot to league champion. In the process, I had to beat my son, Jan, which made it all that much more special.

I also won the championship in another league I played in; so I won two out of the three leagues I played in last year. The prize money totaled over $2000.00! Did I mention we have this huge, gaudy trophy that holds about 30 ounces of beer for the Champ to keep on his mantle for the whole next season?

Like any good astronomy freak, I spent my winnings buying astronomical equipment. I bought a CCD auto-guider, mounting rings and an 80mm guide scope. I also purchased a treadmill which we have in the living room, in front of the plasma TV.

Fast forward to the present. This is the first week of playoffs and you guessed it, I am playing my son in the first round in the league we play in together. Bragging rights at Christmas dinner and $600 are at stake so this is serious business! I'm also leading the pack in another league I play in, so I'm looking at finishing in the money in 2 out of 4 leagues this year.

The AAVSO meeting in April will be held in Argentina this year. If I win both leagues, I might actually be able to afford to fly Irene and myself there. If my teams sputter in the playoffs, it's doubtful we will spend the money, in spite of it being a once-in-a-lifetime opportunity.

Funny how even my distraction of fantasy football has turned into an astronomy related activity; and one with such important ramifications. It's really not that hard to understand. I'm spoiled. I love what I do, I'm passionate about it, no matter what it is I'm doing, and I would be totally bored if it were any other way.

We want to go to the southern hemisphere and see the sky down under.

Go Runnamuckers...
Go Belichick's Hoodie!

Carnival of Space #133

The 133rd Carnival of Space is hosted this week at Next Big Future. Next Big Future is a blog featuring articles about nanotechnology, nuclear and energy technology, quantum computers, life extension, space technology and AI. Proposing and tracking the best societal, business and technical choices to the next big things that will shape our future. Check out the passenger configuration video for current aircraft and future space flight. I would kill for a nice big seat with the option to lay down on those long trans-oceanic flights.

I guess I was in more of a look at the pretty pictures mood as I read through the Carnival this week. My favorites were:

The exploration of Eddington crater, from the authors own telescope to views retrieved and produced online gives you an idea of all the tools amateur astronomers and citizen scientists have at their disposal these days. Two big thumbs up from the Simostronomer.

Bad Astronmer, Phil Plait, actually did a blog about astronomy last week, covering the mosaic image of galaxies from the Canada-France-Hawaii Telescope Legacy Survey Deep Field #1. I'll give him props for showing me the cool 'zoom in to freak out' tool from CFHT. Hubble has a zoom in tool online now too you can find here.
Check these and the other great pieces out at Carnival of Space 133.

Slacker Astronomy on 365 Days of Astronomy

Michael, Doug and I talk about "heat!" What is heat? What is temperature? What is the difference? What does any of this have to do with astronomy?
We take a crack at explaining it all on 365 Days of Astronomy. You tell me; how did we do?
My fear is the end result was something like this:

To prove my hypothesis there is a longer version of this discussion on the Slacker Astronomy site also!

I'll be interested in the comments this time around.