astronomy

All posts tagged astronomy

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NASA’s Juno Mission, designed to probe Jupiter’s deep interior and unlock the origin of the solar system, will arrive at the planet on July 4th.

Stay up late with Boise State Physics to celebrate on July 4th 10p-12a on the Brady Street Garage. Come watch the fireworks and stay to view Jupiter, Saturn, and Mars.

Free public parking will be provided by Boise State University in the Brady Garage (accessible from Brady Street).

Information at bit.ly/BSUJupiterEvent or from Brian Jackson (bjackson@boisestate.edu).

OsherPagesTopPic2015I gave a talk at Boise State’s Osher Lifelong Learning Institute on exoplanets generally and my group’s research specifically.

The crowd was really amazing. Despite my being delayed by a flat bike tire, there was an enormous group of enthusiastic astrophiles waiting for me when I arrived.

We toured the night sky briefly using the stellarium program, a free (but please donate) and open-source night sky simulator available here — http://stellarium.org/.

I made quite a long talk to fill the two-hour scheduled slot, but there were so many interesting questions, I barely made it halfway through. I’ve posted my abstract and presentation below in case there’s any interest.

The Exoplanet Revolution

The discoveries of hundreds of planets outside our solar system, called exoplanets, have led to a renaissance in astrophysics and revolutionized every sub-discipline within planetary astronomy. The vast array of new planets strains imagination, and even after two decades of discovery, exoplanets pose a host of astrophysical riddles. In this presentation, I’ll describe how these distant worlds have revised our picture of planet formation and evolution. I’ll also discuss outstanding questions in planetary astrophysics and prospects for observational work, including the TESS mission, selected by NASA for a 2017 launch to find more, nearby planets.

IMG_3637Had a wonderful visit to London, Ontario last week, home of the University of Western Ontario. Weather wasn’t quite as nice as here in Boise, but the city was just as beautiful.

My friend and colleague Catherine Neish arranged for me to give three talks while there — one on our crowd-funding effort, one on my exoplanet research, and one on our dust devil work.

I’ve posted two of the talks and abbreviated abstracts below. The dust devil talk, “Summoning Devils in the Desert”, is a reprise of a previous talk, so I didn’t include it below.

Crowdfunding To Support University Research and Public Outreach
In this presentation, I discussed my own crowdfunding project to support the rehabilitation of Boise State’s on-campus observatory. As the first project launched on PonyUp, it was an enormous success — we met our original donation goal of $8k just two weeks into the four-week campaign and so upped the goal to $10k, which we achieved two weeks later. In addition to the very gratifying monetary support of the broader Boise community, we received personal stories from many of our donors about their connections to Boise State and the observatory. I’ll talk about our approach to social and traditional media platforms and discuss how we leveraged an unlikely cosmic syzygy to boost the campaign.

On the Edge: Exoplanets with Orbital Periods Shorter Than a Peter Jackson Movie
In this presentation, I discussed the work of our Short-Period Planets Group (SuPerPiG), focused on finding and understanding this surprising new class of exoplanets. We are sifting data from the reincarnated Kepler Mission, K2, to search for additional short-period planets and have found several new candidates. We are also modeling the tidal decay and disruption of close-in gaseous planets to determine how we could identify their remnants, and preliminary results suggest the cores have a distinctive mass-period relationship that may be apparent in the observed population. Whatever their origins, short-period planets are particularly amenable to discovery and detailed follow-up by ongoing and future surveys, including the TESS mission.

Among other fun things I did this week during spring break, I practiced using one of the Physics Dept.’s new telescopes. It’s a lovely little 127-mm Maksutov-Cassegrain with a robotic mount. I also used a NexImage 5 camera. While the telescope is a joy to use, the camera is a pain, and I can’t convince it to return color images.

In any case, I took advantage of the clear night on Friday and imaged Jupiter from the middle school baseball field across the street from my house. In spite of the fact that neither the seeing nor tracking were great, some post-processing with Registax returned a nice little image.

Jupiter, from my backyard.

Jupiter, from my backyard.

Next steps: I need to do a better job with the tracking (probably need some new gear to improve the telescope alignment). A new camera might also be in order.

 

 

 

 

From http://www.redshift-live.com/binaries/asset/image/25908/image/Graviational_Waves.jpg.

From http://www.redshift-live.com/binaries/asset/image/25908/image/Graviational_Waves.jpg.

Nothing. They just waved.

Led by physics major Tyler Wade, this week’s astronomy journal club discussed the very exciting result from the LIGO collaboration, the first detection of gravitational waves.

Einstein predicted the existence of gravitational waves back in 1916. (If your differential geometry and German are any good, you can read the original paper here.) Essentially, gravitational waves are a consequence of that fact that mass can distort the shape of space (that’s what we call gravity).

The upshot of this is that any massive object in motion can excite gravitational waves, but only very massive objects (like, black hole-sized) produce waves big enough that we have any hope of measuring them.

And so for the last few decades, the LIGO project, along with other gravitational observatories, has been monitoring the space-time continuum, looking for tiny distortions due to rapid, oscillatory motion of massive celestial bodies.

LIGO attempts to detect these distortions by sending two laser beams, one each, out and back along two orthogonal 4-km tunnels. By measuring the travel time for each laser beam down each tunnel, they can determine their lengths to a ridiculous precision. A passing gravitational wave would VERY slightly modify the tunnel lengths in a particular way.

How slightly? The signal reported last week by LIGO corresponds to a change in the tunnel length by 0.0000000000000000000001 meters. That’s the equivalent of a change in the width of the Milky Way galaxy by 1 meter.

At two different observatory sites, one in Washington state and the other in Louisiana, the LIGO collaboration measured the distinctive signature of gravitational waves generated by two black holes, many times the mass of the Sun, as they completed their death spiral, merging into an even bigger black hole and radiating an enormous amount of energy.

Why is this important? Well, seeing gravitational waves is not going to allow us to control gravity (at least not yet), and the fact that they exist is not surprising. Instead, LIGO has provided us a brand-new way of doing astronomy.

It’s as if, up until now, we were doing astronomy colorblind, and suddenly LIGO built a color telescope. Of course, being able to see in color would open up vast and unexpected vistas on the universe. The detection of gravitational radiation is the same kind of revolutionary achievement.

NYT has a really great animation and video describing how the detection worked, which I’ve embedded below.

The red dots show the observations, with the dips due to asteroid chunks transiting the white dwarf. The inset shows an artist's conception of the disruption process.

The red dots show the observations from this study, with the dips due to asteroid chunks transiting the white dwarf. The inset shows an artist’s conception of the disruption process.

For our second journal club meeting this semester (didn’t manage to blog the first one), we discussed a study from Saul Rappaport and colleagues on observations of the white dwarf WD 1145+017, which continues to show evidence that it is eating a small asteroid.

A study last year from Vanderburg and colleagues (which we discussed last semester) presented observations from the K2 Mission showing distinctive but highly-variable transit signals coming from WD 1145+017. That group conducted follow-up observations that pointed to the presence of an asteroid very close to the star, being ripped apart by the star’s gravity.

As crazy as it sounds, the idea that some white dwarfs are eating asteroids is fairly well-established, but Vanderburg’s study was the first to present observations of the process clearly in action. The variability of the transit signals indicates that the violent process is dynamic and complicated.

This new study from Rappaport and colleagues continues the saga of WD 1145+017 and finds that the disruption process persists more than a year after the initial observations. And using the apparent drift rates of the different chunks of asteroid, Rappaport is able to constrain the mass of the parent asteroid to be about 1% that of Ceres in our solar system.

One of the most exciting aspects of this study for me is that the observations were made using a network of small, amateur telescopes. Some of the scopes used in the study were 25-cm, and so I’m hopeful that, in the near future, we will be able to use Boise State’s own Challis Observatory to conduct follow-up. Just gotta wait for a clear night.

Last week, I had a lovely visit to the Astronomy Dept at New Mexico State University in beautiful Las Cruces. I was invited to give one of the dept’s weekly colloquia about our research group’s work on very short-period exoplanets. While there, I talked dust devil science with my host Prof. Jim Murphy, his student Kathryn Steakley, and Lynn Neakrase.

I also enjoyed some excellent Mexican food at the Double Eagle Restaurant, which has been haunted by the ghosts of two young lovers since just after the Mexican-American War.

The International Space Station passing over Mesilla, NM on 2015 Dec 4.

The International Space Station passing over Mesilla, NM on 2015 Dec 4.

Just before dinner, the ISS also passed directly over our heads, and I got a very poor photo of it (left).

So, all in all, a great visit.

 

 

I’ve posted my abstract and presentation below.

On the Edge: Exoplanets with Orbital Periods Shorter Than a Peter Jackson Movie


From wispy gas giants to tiny rocky bodies, exoplanets with orbital periods of several days and less challenge theories of planet formation and evolution. Recent searches have found small rocky planets with orbits reaching almost down to their host stars’ surfaces, including an iron-rich Mars-sized body with an orbital period of only four hours. So close to their host stars that some of them are actively disintegrating, these objects’ origins remain unclear, and even formation models that allow significant migration have trouble accounting for their very short periods. Some are members of multi-planet system and may have been driven inward via secular excitation and tidal damping by their sibling planets. Others may be the fossil cores of former gas giants whose atmospheres were stripped by tides.

In this presentation, I’ll discuss the work of our Short-Period Planets Group (SuPerPiG), focused on finding and understanding this surprising new class of exoplanets. We are sifting data from the reincarnated Kepler Mission, K2, to search for additional short-period planets and have found several new candidates. We are also modeling the tidal decay and disruption of close-in gaseous planets to determine how we could identify their remnants, and preliminary results suggest the cores have a distinctive mass-period relationship that may be apparent in the observed population. Whatever their origins, short-period planets are particularly amenable to discovery and detailed follow-up by ongoing and future surveys, including the TESS mission.

We had our last research group meeting of 2015 on Friday since finals are coming up soon. Fairly large crowd, though, for a meeting so late in the year.

Artist's conception of Vanderburg's disintegrating body. From https://www.cfa.harvard.edu/~avanderb/page1.html.

Artist’s conception of Vanderburg’s disintegrating body. From https://www.cfa.harvard.edu/~avanderb/page1.html.

We discussed Andrew Vanderburg’s discovery of a disintegrating minor body orbiting a white dwarf star.  The body, as small as Ceres or smaller, is so close to its host star that it’s actively evaporating and falling apart, and the shadows of the resulting dust cloud is visible data from the K2 Mission. The dust then falls onto the white dwarf, polluting its atmosphere in a way we can see spectrally.

We also had a very impressive presentation from Hari Gopalakrishnan of Renaissance High School on a recent study from Jim Fuller at Caltech. Fuller and colleauges analyzed oscillations at the surface of a red giant star to infer the presence and strength of magnetic fields deep in the star’s interior. Hari kindly shared the presentation, which I’ve linked below.

Attendees at this journal club included Jennifer Briggs, Karan Davis, Emily Jensen, Tyler Gordon, Steven Kreyche, Jake Soares, and Hari Gopalakrishnan.

k2scicon_web_bannerOn my way back to Boise from the first K2 Science Conference, a week-long conference on the K2 Mission, successor to the Kepler mission.

Although I had to leave only two days into the conference (gotta get back to teach about the Origins of Earth Life), I got to see some amazing talks.

Talks that really stick out in my mind include Natalie Batalha‘s talk about the frequency of Earth-like planets (one for every three Sun-like stars); Roberto Sanchis-Ojeda‘s talk on a disintegrating planet with a cometary tail; and Jim Fuller‘s talk about measuring magnetic fields deep in the hearts of red giant stars by studying waves on the stars’ surfaces. The burritos at Sandbar on State St. are also pretty amazing.

All in all, a dazzling conference in refreshing Santa Barbara, CA.