Archive for extrasolar planets

It’s Official, it’s PLATO!

Posted in Science Politics, The Universe and Stuff with tags , , , , on February 19, 2014 by telescoper

Just a quick post to pass on the news that the European Space Agency has officially selected the third M-Class mission to form part of its Cosmic Vision Programme (which covers the period 2015-2025). The lucky winner is PLATO (PLAnetary Transits and  Oscillations of stars) and it will detect extra-solar planets by monitoring relatively nearby stars, searching for tiny, regular dips in brightness as planets transit in front of them. It will also study astroseismological activity, enabling a precise characterisation of the host star of each planet discovered, including its mass, radius and age.

plato_satelliteIt is expected that PLATO will find and analyse thousands of  such exoplanetary systems in this way, with an emphasis on discovering and characterizing Earth-sized planets and super-Earths in the habitable zone of their parent star. PLATO will be launched on a Soyuz rocket from Europe’s Spaceport in Kourou by 2024 for an initial six-year mission. It will operate from the Second Lagrange Point, or L2 for short. It’s an intriguing design consisting of 34 small telescopes (left).

PLATO joins Solar Orbiter and Euclid, which were chosen in 2011 as ESA’s first two M-class missions. Solar Orbiter will be launched in 2017 to study the Sun and solar wind from a distance of less than 50 million km, while Euclid, to be launched in 2020, will focus on dark energy, dark matter and the structure of the Universe.

The decision to select PLATO wasn’t exactly a surprise as it was singled out as the leading candidate by an expert panel last month, but there was nevertheless some nervousness among certain senior astronomers at the Royal Astronomical Society on Friday in advance of the formal decision. I suspect they’ll all be out celebrating tonight!

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Astronomy Jobs at Cardiff!

Posted in The Universe and Stuff with tags , , , , , on June 1, 2012 by telescoper

Just a quick post to advertise a couple of job opportunities in the School of Physics & Astronomy at Cardiff University. For further details you can look at the official website, but here is an outline:

Two Faculty Positions in Astrophysics

Observational and theoretical studies of star-formation and/or extrasolar planetary systems.

The School of Physics and Astronomy at Cardiff University has immediate vacancies for two permanent faculty appointments in Astrophysics.  We are seeking experts in observational and theoretical studies of star-formation and/or extra-solar planetary systems to conduct world-class research and research-led teaching at undergraduate and postgraduate level.  The appointments will be at any level from Lecturer to Professor depending on the experience of the candidate; we expect at least one of the appointments to be at a junior level.

Physics and Astronomy at Cardiff University has undergone substantial expansion in the past few years and has very strong research groups in gravitational-wave physics, astronomical instrumentation, extragalactic astronomy and cosmology, star-formation and condensed matter physics.  There are presently 18 academic staff involved in astrophysics and relativity, with 15 post-doctoral researchers and 22 PhD students.

The appointment will be made at a level commensurate with experience.

The advertisement is also available on the AAS Jobs Register, or will be when they get their act together and put it online. The AAS website is just one of a number that have been recently improved, with the result that they’re much less efficient than they were before.

Anyway, I’m just passing on the advertisement so please don’t send me your CVs! If you’d like to apply please do so using the official Cardiff University jobs page, which also has a lot of general information about the City and the University.

P.S. There have been quite a few job vacancies in astronomy around the UK recently – Edinburgh, Surrey, Liverpool, Exeter etc. I wonder why that is, and where the money is coming from?

Cosmic Vision

Posted in Science Politics, The Universe and Stuff with tags , , , , , , , , , on February 20, 2010 by telescoper

It’s nice to have a bit of science stuff to blog about for a change. Just this week the European Space Agency (ESA) has  announced the results of its recent selection process for part of its Cosmic Visions programme, which represents ESA’s scientific activity for the period 2015-2025.

The selection process actually began in 2007, with over 50 proposals. This list was then whittled down so that there were six candidate missions under consideration for the so-called M-class launch slots (M meaning medium-sized), and three in the L-class list of larger missions. The latest exercise was to select three of the M-class missions for further study. They succeeded in selecting three, but have also kept another, much cheaper, mission in the frame.

As far as I understand it, only two M-class missions are actually envisaged so the race isn’t over yet, but the missions still in the running are:

PLATO.  The PLATO mission is planned to study planets around other stars. This would include terrestrial planets in a star’s habitable zone, so-called Earth-analogues. In addition, PLATO would probe stellar interiors by through stellar seismology. In some sense, this mission is the descendant of a previous proposal called Eddington. (PLATO stands for PLAnetary Transits and Oscillations of stars – I’ll give it 3/10 for quality of acronym).

EUCLID. Euclid would address key questions relevant to fundamental physics and cosmology, namely the nature of the mysterious dark energy and dark matter. Astronomers are now convinced that these substances dominate ordinary matter. Euclid would map the distribution of galaxies to reveal the underlying ‘dark’ architecture of the Universe. I don’t think this is meant to be an acronym, but I could be wrong. Perhaps it’s European Union Cosmologists Lost in Darkness?

SOLAR ORBITER. Disappointingly, this is neither an acronym nor a Greek person. It would take the closest look at our Sun yet possible, approaching to just 62 solar radii. It would deliver images and data that include views of the Sun’s polar regions and the solar far side when it is not visible from Earth.

These are the three main nominations, but the panel also decided to endorse another mission, SPICA, because it is much cheaper than the approximately 500 Million Euro price tag on the other contenders. SPICA would be an infrared space telescope led by the Japanese Space Agency JAXA. It would provide ‘missing-link’ infrared coverage in the region of the spectrum between that seen by the ESA-NASA Webb telescope and the ground-based ALMA telescope. SPICA would focus on the conditions for planet formation and distant young galaxies.

Many of Cardiff’s astronomers will be very happy if SPICA does end up being selected as it is the one most directly related to their interests and also their experience with Herschel which is, incidentally,  continuing to produce fantastic quality data. If SPICA is to happen, however, extra money will have to be found and that, in the current financial climate, is far from guaranteed.

Which of these missions will get selected in the end is impossible to say at this stage. There are dark mutterings going on about how realistic is the price tag that has been put on some of the contenders. Based on past experience, cost overruns on space missions are far from unlikely and when they happen they can cause a great deal of damage in budgets. Let’s hope the technical studies do their job and put realistic figures on them so the final selection will be fair.

Whatever missions fly in the end, I also hope that the Science and Technology Research Council (STFC) – or whatever replaces it – remembers that these are science missions, and its responsibility extends beyond the building of instruments to fly on them. Let’s to hope we can count on their support for research grants enabling us to answer the science questions they were designed to address.

On First Looking into Chapman’s Homer

Posted in Poetry, The Universe and Stuff with tags , , on November 19, 2008 by telescoper

As a present to those who appear disgruntled by my comments about exoplanets here and there, this is from John Keats:

 

Much have I travell’d in the realms of gold,
    And many goodly states and kingdoms seen;
    Round many western islands have I been
Which bards in fealty to Apollo hold.
Oft of one wide expanse had I been told
    That deep-brow’d Homer ruled as his demesne;
    Yet did I never breathe its pure serene
Till I heard Chapman speak out loud and bold:
Then felt I like some watcher of the skies
    When a new planet swims into his ken;
Or like stout Cortez when with eagle eyes
    He star’d at the Pacific–and all his men
Look’d at each other with a wild surmise–
    Silent, upon a peak in Darien.
 

This famous sonnet was written in October 1816 and is considered the highlight of Keats’s first volume of poetry. It was originally a gift for his friend, Charles Cowden Clarke. The two men had spent an evening reading George Chapman’s superb 17th century translation of the Iliad and Odyssey.

Please note lines 9 and 10. I’m sure they capture the excitement of discovery although Keats probably wasn’t using the correct IAU nomenclature. I’m not sure about the bit about being “silent” either.

Science and Stamp Collecting

Posted in Books, Talks and Reviews, The Universe and Stuff with tags , , on November 18, 2008 by telescoper

Musing over the comments posted on my (slightly ironic) blog item about exoplanetary ennui, I remembered a piece I wrote for the Times Literary Supplement last summer so I dusted it off, chopped it up, and updated it for presentation here because it expands a bit on the earlier contribution.

If the Sun were the size of a golf ball, then the Earth would be a speck of dust a few metres from it and the nearest star would be hundreds of kilometres away. And this is what it is like in the relatively crowded environment of the Milky Way. The unimaginable scale of our Universe means that astronomy has never really become an experimental science, but has largely remained an observational one, having more in common with, say, archaeology than chemistry or other laboratory-based disciplines. Consequently, even though it is perhaps the oldest science, it is also in some respects the least mature. The absence of the traditional interplay between theory and experiment, the inability to perform repeated experiments under slightly different conditions, and the sheer difficulty of measuring anything at all have stunted its development compared to younger fields. For this reason, one often finds in astronomy certain tendencies that other subjects have largely grown out of, such as an unhealthy mania for classification and nomenclature.

Taxonomy has its place within the scientific method: modern chemistry owes much to Dmitri Mendeleev‘s periodic table; botany could not have progressed without Linnaeus; and the theory of evolution was founded on Charles Darwin‘s painstaking studies on the Galapagos Islands. But arranging things in groups and giving them names does not in itself constitute scientific progress, no matter how systematically it is done. The great experimental physicist Ernest (Lord) Rutherford dismissed this kind of activity as not science but “stamp collecting”.

This brings us to the grand debate that took place in Prague in the summer of 2006 under the auspices of the International Astronomical Union. One of the problems before the IAU’s 26th General Assembly was what to do about the fact that recent investigations have revealed the presence of a number of objects orbiting the Sun that are ostensibly at least as worthy of the name “planet” as Pluto, which in our current textbooks is the ninth one out. Obviously, which objects should be called planets depends on how you define what a planet is. The solar system contains objects of all shapes and sizes, from tiny asteroids to immense gas giants such as Jupiter and Saturn. Where should one draw the line? The original proposal was to increase the number of planets to twelve by admitting some lowly new members to the club, but in the end the IAU decided to demote Pluto to the status of a “dwarf” planet thus restricting the number of true planets to eight. This was a controversial decision, at least in the United States, because the vital vote was taken on the last day of the meeting when most of the US delegates had to take flights home. Pluto was discovered by an American, Clyde Tombaugh, in 1930, so the decision deprived the nation of its only planet-discoverer.

The “no” decision hinged on the adoption of three criteria: that the object be round, i.e. have a shape determined by internal gravitational forces; that it should have cleared its own orbit of debris; and that it should be orbiting our own star, the Sun. None of these has any special scientific value; the resulting decision was therefore pretty arbitrary. Moreover, deep-space observations have led to the discovery of literally hundreds of planetlike objects orbiting other stars. These exoplanets offer much greater prospects for scientific progress into the general theory of planet formation than the few objects that happen to have formed in our particular vicinity, so why are they excluded from the definition? In any case, what have we learned scientifically from the new nomenclature? Pluto is still the same object that it was before August 2006, and astronomers still don’t understand what one can infer from its own particular properties about the general process of planet formation.

So is Pluto a planet?

Who cares? In this case there really is nothing in a name. When I was asked this question on the telephone by a reporter I gave precisely that answer and he was shocked. I’m sure he thought that all that astronomers do is look at things and give them names. There are some that do that, of course, but most of us prefer doing proper science.

In the field of exoplanet research we are seeing real signs of maturity, although current studies are still firmly rooted in the “discovery” and “classificatuion” stage. Witness last weeks press interest in the first directly imaged exoplanets. I am well aware of the immense potential that those pictures have for stimulating interest in science, but there is still a long way to go before this field reaches its prime. That probably makes it an excellent area for young scientists to work in. But ultimately this youthful exuberance should give way to something a bit more serious, which is to go beyond what these discoveries are in themselves and ask what deeper questions they might answer.

One can see many other parallels in the history of astronomy, such as the discovery of quasars in the late 1950s. The first few of these must have generated a huge amount of excitement because they were not at all understood. Within a few years hundreds had been detected by radio observations but their nature remained unknown. The subsequent identification of redshifted hydrogen emission lines in the spectra of these objects led to them eventually being identified as very distant extragalactic sources of immense intrinsic power. By the 1980s quasars were identified as a particular type of active galaxy and placed within a general classification scheme that also involved blazars, Seyfert galaxies, and so on. Nowadays we have samples of tens of thousands of quasar spectra and the interest evolves around how the activity in their nucleus relates to the process of galaxy formation in an expanding Universe and how we can use these objects to map out the large-scale distribution of matter. To an outsider these tasks may seem less glamorous that the early days of quasar research, but that’s what science is like.

At the extreme end of the distance scale of astronomical investigation lies my own field of cosmology, the scientific study of the Universe as a whole. The scale of the solar system is challenging enough, but the cosmos is really big. Until recently, cosmology was so lacking in reliable observational input that it was thought of as a flaky offshoot of astronomy, more a branch of metaphysics than a proper scientific discipline, a paradise for theoreticians whose wildest speculations stood no chance of ever being tested with real measurements. Over the past twenty years or so, however, staggering advances in astronomical instrumentation have allowed astronomers to probe the darkest depths of space, capturing light that has travelled for almost 14 billion years on its way towards us. Theories are now so tightly constrained by these observations that there is very little room for manoeuvre. From this interplay between conjecture and refutation has emerged a cosmological framework that accounts, at least in a broad-brush sense, for how the Universe is constructed and how it is evolving.

There are some important gaps, including some puzzling anomalies, and the precise nature of many of its constituents is yet to be understood, but the establishment of the “concordance model” is a sign that cosmology really has come of age.

When you’ve seen one planet….

Posted in The Universe and Stuff with tags on November 14, 2008 by telescoper

Rumours have been circulating for several days and now we have confirmation. The most exciting news in the history of the Universe! Planets exist

Well, actually, we knew that. We live on one. And anyway, the International Astronomical Union recently stipulated that planets could only be things orbiting the Sun.  Don’t ask me why. So the new things have to be called exoplanets. And over 300 hundred of these were known before today anyway.  A rose by any other name would smell as sweet, so we won’t worry about the taxonomy. But what’s the big deal?

2008111311What is different about the most recent observations, reported in today’s issue of Science, is that they involve direct detection (i.e. imaging) of exoplanets, not indirect inferences made by studying stellar wobbles. An example is shown here: the three red dots are the exoplanetary objects orbiting around the star HR 8799.

 Quite interesting.

But is every new detection of an exoplanet going to be hyped like this from now until doomsday? Or until the public gets thoroughly bored?  Might it not be better to wait until there’s a sufficiently large and unbiased sample that exoplaneticists can quit their stamp collecting and start doing some real science?

At least in cosmology nobody ever exaggerates the importance of their discoveries.

*cough*