Imaging Extrasolar Planets: with the European Extremely Large Telescope

Imaging Extrasolar Planets:  with the European Extremely Large Telescope

There is, in the pipeline, a new and even larger ground-based optical telescope known as the E-ELT, (European Extra Large Telescope), for short.   It is to be built in Cerro Armazones, Chile near the Paranal Observatory; just 20Km from the existing VLT (Very Large Telescope).   The planned completion date of the E-ELT, if all goes to plan, is sometime in 2022.  The E-ELT general specifications are as follows:

Organisation: European Southern Observatory (ESO)

Altitude:  3,060 metres

Weather: 89% clear fraction 0.67"median seeing @ 500nm

Wavelength: Visible light ~ Near Infrared range.

Instrument type: Optical Reflector

Mirror Diameter: 39.3 m (segmented primary) a new unique 5 mirror design; each mirror can distort its shape 1000 times per second to correct the image for atmospheric distortions, a system known as adaptive optics.

Angle of arc:  0.0001 to 0.65 arcseconds

Collecting area: 978 m2

Focal Length:  420-840m (f/10 ~ f/20)

Dome:  86 metres in diameter, half the size of a football stadium.

Website:  ESO E-ELT

The initial designs had planned to create a mirror with a 42-metre mirror area.  But, because of inherent design problems, this was reduced to 39.3 metres, which saved 220 million euros, reduced the cost to 1.055 billion euros, and shortened the project time to just 10years.

The E-ELT will be the worlds largest eye on the sky. Its light-gathering potential will be 15 times greater than that of any existing telescope.  It will produce images 15 times sharper than those provided by the Hubble space telescope and is planned to enable astronomers to probe the planetary systems around local stars in the Milky Way galaxy, and in addition, stars still in their formative stages.   It will be a giant leap forward in space exploration that will help astrobiologists detect water,   organic molecules, and possibly atmosphere on extrasolar planets orbiting other stars.  Other targets will be proto-planetary disks circling young stars, with planets in the making.  In addition, it will allow us to study distant gas giants like Jupiter and Saturn in greater detail. 

Ultimately E-ELT will probe deeper into the universe, looking at even more distant objects, chasing answers to the big questions.  This will include detailed studies of the most distant objects, and possibly measure the speed at which the universe is still expanding.

    Comparison with other large Earthbound telescopes:

                                  Name              Aperture Diameter  Collecting Area    State of Play

    Gran Telescopio Canarias  (GTC)            10.4m              74 m2    Largest currently in service 

    Keck Telescopes                                  10.0m              76 m2    Currently in service

    South'n African Large Telescope (SALT) 11.1 x 9.8m     79 m2   Due at end of the decade 

    Giant Magellan Telescope (GMT)            24.5m           368 m2    Due at end of the decade

    Thirty Meter Telescope (TMT)                 30.0m           655 m2    Due at end of the decade

    European Extremely Large Telescope  (E-ELT)

                                                             39.3m           978 m2    Due 2022  

 E-ELT's suite of instruments will help with investigating how objects form and evolve.   Identifying variations in physical constants with time.   The unambiguous detection of variations will advance the understanding of the laws of physics as we know them.

There are additional scientific instruments, adjuncts to the E-ELT, the aim is to switch from one instrument to another in moments, and move the dome rapidly to start a new observation in minutes

 Eight different instruments are planned:

CODEX:  A narrow field optical spectrograph (it separates incoming waves into a frequency spectrum ~ generated via a Fournier transform).

EAGLE:  A wide-field multi-channel integral-field near-infrared (NIR) spectrograph with multi-objective adaptive optics.

EPICS:  An optical/NIR planet imager and spectrograph with extreme adaptive optics.

HARMONI:  A single field, wide-band integral field spectrograph.

METIS:  A mid-infrared imager & spectrograph.

MICADO:  A diffraction-limited near-infrared camera (An optical system with the ability to produce images with angular resolution).

OPTIMOS:  A wide-field visual multi-object spectrograph.

SIMPLE:  A high-spectral-resolution NIR spectrograph.

The two post-focal adaptive optics modules currently being studied are:

ATLAS:  a laser tomography adaptive optics module.

MAORY: A multi-conjugate adaptive optics module.

The inception of the E-ELT project was rooted in the first decade of the 2000's. At that time a number of similar projects were on the drawing board.   The GTC, SALT, GMT, TMT, they are all due to come online before the end of this current decade.   You may wonder if the E-ELT is overkill?   But, the Astronomical community are close-knit and plan ahead with a lot of international cooperation.   Each project is planned to fill a niche in the search for further knowledge about the universe.   Each complex fulfils a need in that scientific community.   Science is a truly multinational fraternity, why else would a consortium of nations invest 1.055 billion euros setting up a telescope array in another country, such as Chile and call it a European telescope?   Surely this should point out the path to be followed by the Nations of this world.   That working together is the only logical way for humanity to progress.

The visible universe is no more than 5% of what is out there, the rest is made up of Dark Energy 72%, and Dark Matter 23%:

https://www.youtube.com/watch?v=gHium3r7qco

The time of discovery is not at an end, it is just beginning...

The Io Observer is a New Frontiers Class mission

The Io Observer is a New Frontiers Class mission

Io is Jupiter's  5th moon (3rd largest and slightly larger than our moon) orbiting at around 422,000 Km.   The significance of Io is that it is the most geologically active body in the solar system, with over 400 active volcano's many the height of Everest.  The highest recorded magma temperatures ~ 1800 degrees Celsius, far higher than that recorded on the earth, suggesting the magma is more primitive and that there is a magma ocean beneath the surface. Possibly duplicating conditions that existed on earth before life began.

The Io Observer mission is designed to determine the internal structure of Io and to learn about its volcanic activity which could have real applications to the nature of volcanoes here on earth.  The mission will be funded by NASA, including the cost of the launch.   None of the four proposed options require new technology and, two of the proposals fall within the new frontiers cost cap, the other two are marginally higher.

Because Io is situated within Jupiter's radiation belt it presents significant challenges to the engineers involved, but the benefits from solving these problems now will result in payback, in the near future, when even more challenging missions are contemplated.  The Io Observer is, as its name implies to be a remote observation mission, under the guidance of the National Research Council's (NRC's) Satellites Panel.   They have four suggested study options using similar equipment to investigate variations in payload, power systems, and mission duration.  Those options are as follows:

1. An advanced Stirling radioisotope generator (ASRG)-powered remote sensing spacecraft.  This will involve ten flybys.
2. A solar-powered remote sensing spacecraft.  This will involve ten flybys.
3. A Solar-powered remote sensing spacecraft with one less instrument and a shorter observational period compared to option 2.   This will involve six flybys.
4. A Solar-powered remote sensing spacecraft with one more instrument compared to option 2.   This will involve ten flybys.

For all options the spacecraft will enter into a highly elliptical orbit of Jupiter, to minimise radiation exposure, while performing periodic Io flybys; this will allow for multiple viewing of Io's polar regions.  A series of close flybys would enable higher resolution mapping and details of the magnetic field, species in the atmosphere and plume to be analysed and allow greater understanding of the internal stresses, strains, put on Io's internal structure by the gravitational pull of Jupiter.   This phase would last approximately 60 days, and would include:

• A redundant 3-axis stabilized spacecraft carrying a narrow-angle camera (NAC), to measure peak lava temperatures with near-simultaneous colour imaging to tightly constrain peak lava temperatures.
• A thermal mapper, to map & monitor temperatures & heat flow patterns related to the internal structure and tidal heating mechanisms.
• A pair of fluxgate magnetometers (FMG's), to detect magnetic induction and an internal field (if the latter is present).
• In addition, options 1, 2, & 4 will carry an ion and neutral mass spectrometer (INMS), to determine composition and spatial distribution neutrals, that control energy input into the Io plasma torus; determine the composition of Io's atmosphere, volcanic plumes and a whole host of other things.
• Option 4 will also carry a fast-imaging plasma spectrometer (FIPS), to measure the energy, angular, and compositional distributions of the low-energy components of the ion distribution.  The solar-powered versions will require an instrument scan platform that will enable the solar arrays to continually face towards the sun while data collection is in progress. 

Previous missions to the Jupiter system were:

1.     Pioneer 1 & 2 1973/74

2.     Voyager 1 ~ 1979  first reported volcanic eruption.

3.     Voyager 2 ~ 1990  confirmed volcanic activity.

4.     Galileo      ~ 2000  confirmed the volcanic nature of Io.

5.     New Horizons ~ 2007 due to flyby 2016

There is a high Electrical current set up between Io and Jupiter in a cylinder of highly concentrated magnetic flux known as the Io flux tube, of two trillion watts output.  This is comparable to the total power produced on earth. 

The Short Version:

Most of the above technical data goes way over my head.  I understand that there have been six missions that have visited the Jupiter system.   They obtained a lot of information about the Jovian moons some of it was about the anomaly that is Io.  One of the sixty-seven moons (last count), It appears to be a double for earth 4.5 billion years ago.  It's unlikely that it will ever spawn life as we know it, but given enough time anything is possible.   It would be interesting to watch it and draw parallels between the geological activity on Io & Earth.   There are a lot of forces in action between Io & Jupiter, sometime in the future that awesome energy in the Io flux tube (two trillion watts) might be harnessed; anything is possible.   It may sound like science fiction, but if we don't study it we won't learn anything, and Homo sapiens are a curious species.