Publicity in the Baltimore Sun helped.

WBAL coverage of our event.

Peter McCullough’s talk on transits

Maryland Space Grant Observatory TA Chris Martin using the projection method:

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Volunteer Shireen Gonzaga helping guests view through a solar telescope:

Some of the organizers (Veselin, Justin, Scott, Dan) with speaker and Nobelist Adam Riess:

Event schedule:

5 pm – Short talks in the Schafler Auditorium, including one by Nobel Prize winner Adam Riess on the importance of transits in the history of astronomy and cosmology

6 pm to sunset – Observation of transit using Bloomberg’s Maryland Space Grant Observatory telescope (projecting onto paper)

…and using several personal, smaller telescopes set up on the Bloomberg roof

…and using a live feed from Hawaii (projecting in the Schafler Auditorium)

Contact me at richman[at]pha[dot]jhu[dot]edu if you have questions.

If you would like to bring your own telescope, please contact us at least one week before the event so we can make sure it is ok to use. We will have limited space for telescopes on the roof, so please get in touch with us early. See this for directions to the Bloomberg Center: http://physics-astronomy.jhu.edu/dept/directions/index

What makes them special, however, is their unusual history. The authors suggest that these are the remnants (cores) of larger planets that have been immersed inside the star as it expanded to become a Red Giant — the inevitable fate of our own planet. The two probably proceeded into spiraling ever deeper inside the envelope of the gigantic star, losing mass and possibly even driving the evolution of the host itself.

This discovery adds yet another example of the wide variety of environments extrasolar planets can be found in. More importantly, it show how…stubborn…and resourceful planets are in the game of survival. But of course, nothing less is to be expected of the carriers of this most fascinating and robust thing called life.

Main article: iron-sulfur world theory

Current evolutionary theory on the origin of life posits that the first organisms were anaerobic because the atmosphere of prebiotic Earth was, in theory, almost barren of diatomic oxygen. As such, requisite biochemical materials must have preceded life. In vitro, iron sulfide at sufficient pressure and temperature catalyzes the formation of pyruvate. Thus, argues Günter Wächtershäuser, the mixing of iron-rich crust with hydrothermal vent fluid is suspected of providing the fertile basis for the formation of life.

In short, we thought it had a period of 2.8 days and a minimum mass of 14 Mearth.  This is from radial velocity measurements.  The paper from last year, however, made the case that this period may be due to aliasing in the data.  If the planet has a period closer to 0.7 days, it could appear to have a 2.8 day period in radial velocity observations.  And if its period is 0.7 days, then there’s a really good chance that it could transit its star.

Which, it turns out it does.  These new observations confirm it has a 0.74 day orbit, and that it’s mass is much lower: 8.5 Mearth.  But because it’s transiting, we can much more accurately determine its radius: 1.63 Rearth.  This gives it an average density of 11 g cm^-3.  For comparison, that makes it twice as dense as the Earth or Mercury.  For further comparison, that iron meteorite we had at our Physics Fair table (just to the left of Veselin’s laptop in the picture) has a density of roughly 7.5 g cm^-3 and weighs 24.5 lbs.  It was roughly the size of a large dog’s head. If it were a chunk of 55 Cnc e, then it would weigh 36 lbs., roughly a third heavier.

Physics Fair 2011 Astrobiology Table. The iron meteorite in question is to the left of the laptop.

Figure 2 from "Detectability of planetary rings around an extrasolar planet from reflected-light photometry"

Just saw this on astrobites.com: Could Rings Exist Around Kepler “Warm Saturns”?

It’s a new paper on arxiv.org that follows a couple of older papers that try to pin down the detectability of rings around exoplanets.  In this case, the authors are focusing only on planets and candidate planets detected by Kepler.  Astrobites does a good job of summing up the paper, so I’ll just provide a couple of other quick-read papers and a book reference if you’re interested in learning more.

Transit Detectability of Ring Systems Around Extrasolar Giant Planets
Detectability of planetary rings around an extrasolar planet from reflected-light photometry
Planetary Rings

This latter reference, a book from the Cambridge Planetary Science series, is a good introduction to (Saturn’s) rings suitable for undergraduates.

2011-4-16-handouts

Dark Matter And The Habitability of Planets

In many models, dark matter particles can elastically scatter with nuclei in planets, causing those particles to become gravitationally bound. While the energy expected to be released through the subsequent annihilations of dark matter particles in the interior of the Earth is negligibly small (a few megawatts in the most optimistic models), larger planets that reside in regions with higher densities of slow moving dark matter could plausibly capture and annihilate dark matter at a rate high enough to maintain liquid water on their surfaces, even in the absence of additional energy from starlight or other sources. On these rare planets, it may be dark matter rather than light from a host star that makes it possible for life to emerge, evolve, and survive.

I came across this on the always-excellent astrobites.com site.

The beam itself measured 2000 gray as it entered Bugorski’s skull and about 3000 gray when it exited on the other side.  A “gray” is an SI unit of energy absorbed from ionizing radiation.  One gray is equal to the absorption of one joule of radiation energy by one kilogram of matter.  An example where this is commonly used is in X-rays.  For reference, absorption of over 5 grays at any time usually leads to death within 14 days.  However, no one before had ever experienced radiation in the form of a proton beam moving at about the speed of light.

I’m posting this out because it immediately made me think of the interview we did with Dr. DiRuggiero for last week’s 365 Days of Astronomy podcast:

The organism we’re working on at the moment is Halobacterium.  They’re fairly resistant to radiation.  We measure the resistance to radiation as the D10, which corresponds to the radiation doses for which 10% of a population survive.  So the D10 of the organism, that is called the wild type.  The regular organism is five kilo Gray—that’s measured radioactivity—which is pretty high.  This is 5000 Gray, and humans are killed by five Gray.  Those survive 5000 Gray; humans died with five Grays.