Today was the opening day of the American Astronomical Society conference in Washington, D.C. I’m here to learn about NITARP, the NASA/IPAC Teacher Archive Research Program. Seven teachers, including myself, have been selected as a new class to learn how to do original research using the infrared astronomy archive (IPAC) housed at Caltech. We will be presenting a paper on our experience at next year’s AAS conference in Seattle. This coming summer, we’ll bring up to four students with us to Caltech to learn how to use the archives that are part of IPAC.
I had a hard time sleeping the night before, and just barely managed to drag myself downstairs at 9:00 without breakfast to meet with Dr. Rebull, our team’s scientist and director of NITARP. We met inside the exhibit hall, and went over a few more details, such what to do to prepare for writing up our proposals due March 7 and how to get up to speed on our research project. We’ll be looking at K giant stars that have excess lithium to try to determine if that lithium could have come from ingested planets. We’ll look for the signature of a dusty shroud or disk around these stars, which may indicate that a planet had been torn apart by tidal forces as the giant expanded.
Exomoons and Planet Migration
I went to a session on Exomoons and Planet Migration. An exomoon is a moon orbiting a planet which orbits another star besides the sun. So far we have not discovered any, because they are very difficult to detect and verify, but we probably have data from Kepler in the pipeline now that will verify the existence of such moons within the next year or two. The problem isn’t if they exist – they surely do – it’s how do we tease their signals out of the noise. The first talks were about planet migration. One talked about how he had discovered that younger planets have more eccentric (elliptical) orbits, which suggests that some third body (another planet) has deflected the planet into a more elliptical orbit. Then tidal forces and the gravity of residual dust would circularize the orbits. The next talk discussed how planetesimals achieve resonances in the periods of their orbits by interactions with remaining dust.
Zachary Berta-Thompson, a Torres Exoplanet Fellow at MIT, looked at alignments between a star’s spin and the planet’s orbital plane for mini Neptunes, as measured by comparing transit energies. If the depth of the transits change, it could mean the planet is not aligned with background features of the star, such as a sunspot group, and that it migrated closer to the star in a violent fashion. If they are aligned, it means the planet and the sunspots stay lined up, and the planet’s original migration was probably gradual and smooth.
Paul Mason from the Univeristy of Texas El Paso spoke of how the habitable zone (HZ) for P-type planets orbiting both stars in a binary star system would actually be wider and more stable than planets orbiting single stars. He based this on the ideas that the stars would become tidally locked (if their orbits had short periods), which would weaken their magnetic field and lead to a decrease in stellar flux and wind. With less wind, the water on the planet would not evaporate away as easily, leading to more possibility of life. In fact, he claimed that if our sun had a .6 solar mass companion with a 30-day period, then Venus and Mars would both lie inside the HZ and not just Earth. Of course, such Tatooine-like planets are probably rare, but they do exist. We have found them.
Natalie Hinkel of SFSU showed how a moon orbiting a planet might have habitable conditions even if the planet itself does not stay inside the HZ all the time. It all comes down to the actual radiative flux reaching the moon.
Kepler Town Meeting
Steve Howell led a Town Meeting on the Kepler mission and its proposed successor, the K2 mission. The moderator in the previous session has strongly suggested attending this. Kepler lost its second of four reaction wheels last year, effectively ending the primary mission since the telescope could no longer be pointed at the target area with any precision. But the scope still works and has steering propellant, so astronomers have been making suggestions for how it might still be used. Steve went over the close-out timeline for the primary mission, which still has many candidate stars and raw data that need to be confirmed. The properties of stars in the existing catalog need to be better characterized. A final catalog for Kepler Objects of Interest (KOI) will be made, showing which are junk (false positives), which are astronomical objects such as eclipsing binaries or high sunspot stars, and which are truly planets.
The K2 mission will be cool. They will use the remaining two wheels to keep the telescope pointed radially away from the sun along the ecliptic. They will use the thrusters to change the field of view every 85 days, since the scope can yaw more then about 90 degrees with only two wheels and still stay pointed away from the sun. Precision roll will be accomplished by thrusters and balanced pressure from the solar wind. In essence, they will use the telescope as a solar sail. They can still look at areas for about 80 days, enough to see short period planets and other phenomena. Some star clusters, such as the Pleides and Hydes lie along this path and will be studied for planets. It will be interesting to see what sort of planets are found in an open cluster.
Stranded in Miami
My wife called me out of the Town Hall Meeting to say here flight from Miami to Chicago had been cancelled. She has been in Chile visiting her parents (nice place to go during winter). We’ve had a huge polar vortex move south over the entire Midwest and East Coast, bringing terrible wind chill. Chicago’s airport was shut down. She was at the back of the plane, and by the time she got off and got into line for the ticket counter, she was at the end of a long and slow line and all available seats on all flights were full. Thousands of flights are cancelled, and she was unable to find a flight out of Miami until Thursday morning. Meanwhile, our two youngest children are being watched by my sister while I’m in D.C. She has to go back to work tomorrow. We’re not sure what we’re going to do. I went back to my room to try to help her out. Her bags have gone on to Salt Lake and all she has is the clothes on her back, her purse, her cell phone (without a charger), and the blanket she’s crocheting.
I returned to the conference after having lunch (I was starved). I ate at the Pienza buffet in the hotel. This next session was on characterizing exoplanets. The first talk (I missed his name) talked about how we have a better frequency distribution now for the abundances of different planet sizes. At first, we were finding many hot Jupiters because our detection methods favored this, but we now know they are actually quite rare, and the smaller planets a bit larger than the Earth but smaller than Neptune are the most common. Yet we have none of this size in our own solar system. He also looked at the H/He ratios and the relationship between the mass and the size of the planets. He concluded that planets with less than about 10 Earth masses are mostly rocky (less than one percent H/He) and planets larger are more gaseous (>10 % H/He). These findings, coupled with the fact that we are finding fewer brown dwarfs than expected, indicate to me that certain sizes of stellar and sub-stellar objects are more likely. The peaks occur at subNeptunes and at red dwarfs, for some reason.
The next speaker discussed how water clouds are possible on Y-class brown dwarfs. I hadn’t heard this before. So stars can have weather . . . The next speaker used computer simulations to show that giant planets can form around low-mass stars, as many as 10% of the planets formed.
Sarah Ballard of the University of Washington showed how exoplanets can be verified using astroseismology. In other words, the planet’s gravity can create tides in the star that are visible to us as surface radial velocities. She looked at Kepler 93b, and showed how her technique could make planet measurements much more precise because the density of the star can be worked out to milligrams per cubic centimeter using astroseismology. The planet here is only 73 miles in diameter.
Bryce Croll looked at an asymmetric transit depth (deeper on one side than on the other, and fluctuating with time) to suggest the object was a sub-Mercury sized planet just outside the Roche limit and in the process of breaking up. The dust and gas blown off as a plume are creating the asymmetries in the transit curve. Lauren Biddle of the University of Arizona talked about discovering non-transitting planets in a system by looking at the variations in timing for planets that do transit
I then went to the Henry Norris Russell lecture given by Kenneth Freeman from Australia. He talked about how the abundances of elements found on a star’s surface doesn’t change (except for elements under magnesium), so these abundances can be used to identify which stars belong to which open clusters and moving groups (stars that formed together and still move together). Piecing these together brings a picture of the evolution of our galaxy’s structure over time, and helps us know that we are in a barred spiral galaxy. Looking at the motions of these associated stars, we see a kind of bowtie or peanut shape to their orbits around the galactic center from our perspective. We also see different areas of our galaxy, such as the thin disk of the spiral arms, the thick disk, the central bulge, the stellar halo with globular clusters, and the final halo of dark matter. Another interesting fact is to see that metal rich stars are found in the thin disk (arms) and that metal poor stars, even though found in outside now, were formed close to the center of the galaxy where there was less metal available. On a final note, he said we have yet to find the association of which our sun is a part.
After resting in my room and helping my wife, still stuck at the airport in Miami, to get a hotel room, I went out to Thai food with some of the new NITARP teachers. We swapped ideas, especially about making and using videos in the classroom. We’re all scrambling to contact our subs and provide materials while attending the meetings here. I had to leave early to go to a reception and town hall for SOFIA. But I couldn’t stay long there because I had to report to the NITARP group for a debriefing of this past year.
All the previous teams are here now, and there are about 75 of us. We took photos, then met in mixed groups to brainstorm what worked, what didn’t, and how to improve. We made the process go quickly so that we could get to Neil deGrasse Tyson’s talk at 8:00.
I talked briefly with Wendi Laurence, who said the Mohling Award judging was basically done and I needn’t worry about it – I had not heard from her for a while. She must have been using a wrong e-mail address.
Neil deGrasse Tyson
The Potomac Ballroom A was quite full. Tyson is the director of the Hayden Planetarium in New York City and has become quite a celebrity in science popularization circles. He’s appeared on the Big Bang Theory TV show, on Stargate: Atlantis with Bill Nye, and has now even appeared in the DC Comics series of Superman, where he helped Superman see a view of Krypton exploding. He explained how it all got started. When he was newly at the Hayden, the first exoplanet was discovered and the local news station asked him some questions. He went on and on with a great scientific explanation of the radial shift method of planet detection, but the only part that got on TV was him doing a little jiggle to show how the star shifted. He decided never to by sound bit again. So as he was asked questions on camera, he always gave a “tasty” sound bite the press would eat up. Things mushroomed, he made appearances on shows, and has now become quite the celebrity.
The point of his address was to show anecdotes of how there appears to be a groundswell in the public interest in science. He showed how science ideas how entered the public consciousness, even made it into comics and art. And tattoos. He talked about memes and the Twitterverse and showed how his followership jumped when he had done certain things or made certain comments. It was all very interesting and entertaining, although the language used was not appropriate for such an audience.
But he also came across as someone who has crossed the line from scientist to arrogant celebrity. He managed to offend quite a few people in the audience, even going so far as to hint (very strongly) that only uneducated people would have voted for Mitt Romney. Now he’ll claim he never said this, but he did show a slide showing the top 10 states in education level and how they voted (all Democratic) and the lowest 10 states in education level, where all but one voted Republican (the exception was Nevada, where Senator Reid is from). And there were dunce caps on Mitt Romney’s head.
His showing of the slide in this way (without much comment) would imply a causality, without making the necessary scientific addendum that this chart only shows a correlation, not a causation. And in fact the figure’s accuracy is questionable. Look at Utah, which has a high education rate, but voted more strongly for Romney than any other state. Yet exceptions were not mentioned. It’s a case of observational selection. But then he went further into offensive territory to ask how many people in the audience were Republicans by a show of hands – about eight dared to respond. I didn’t, even though I am a Republican. I did not want to invite the public scorn he then heaped upon those who raised their hands, or try to make Tyson’s point for him. It was hardly a scientifically valid poll.
I can’t imagine any responsible scientist acting this way. But I can imagine an uneducated, unenlightened celebrity acting this way. Just because one is famous doesn’t give one the expertise to comment on public policy or any other field. I do not understand how these so-called well-educated people are unable to see that it takes two sides to make an argument, and that our current budget crisis is just as much the blame of the President as it is the Congress. It’s the political polarization that’s hurting us; the inability of either side to reach common ground. I also have a hard time with the apparent liberal attitude that they know what’s best for us and that we all need to be saved from our own ignorance. But I’ll talk about this more in a future post. I need to cool my jets a little.
The highlight of his lengthy ego trip was to show a trailer for the new Cosmos series. That, at least, looks to be worth watching. He described the history behind the new show and why it is going to be on Fox TV. It’s mostly because Fox is willing to put good money into it, whereas PBS wanted to control it all.
After his remarks I walked back to my room. I encountered some of the high school students who had come for NITARP and who had all heard Tyson’s remarks. I asked what they felt of it, and they would only say, “It was OK.” That’s the high school equivalent of saying, “We didn’t like it.” Some of the students were from the very states Tyson’s graphic had said were uneducated. I’m sure that’s going to help persuade them to become scientists . . . I just hope Tyson considers next time that there could be high school students in his audience before sharing R rated language and offensive comments.
I understand the Twitterverse exploded with negative comments after his remarks. Maybe that’s what he had in mind all along – seeing if his talk would create the very types of memes he was describing.