January 10, 2017

Billionaire backed Breakthrough Initiative funds new coronograph on European Very Large Telescope to get scope time to find and study exoplanets around Alpha Centauri

ESO has signed an agreement with the Breakthrough Initiatives to adapt the Very Large Telescope instrumentation in Chile to conduct a search for planets in the nearby star system Alpha Centauri. Such planets could be the targets for an eventual launch of miniature space probes by the Breakthrough Starshot initiative.

ESO, represented by the Director General, Tim de Zeeuw, has signed an agreement with the Breakthrough Initiatives, represented by Pete Worden, Chairman of the Breakthrough Prize Foundation and Executive Director of the Breakthrough Initiatives. The agreement provides funds for the VISIR (VLT Imager and Spectrometer for mid-Infrared) instrument, mounted at ESO’s Very Large Telescope (VLT) to be modified in order to greatly enhance its ability to search for potentially habitable planets around Alpha Centauri, the closest stellar system to the Earth. The agreement also provides for telescope time to allow a careful search programme to be conducted in 2019.

The discovery in 2016 of a planet, Proxima b, around Proxima Centauri, the third and faintest star of the Alpha Centauri system, adds even further impetus to this search.

Knowing where the nearest exoplanets are is of paramount interest for Breakthrough Starshot, the research and engineering programme launched in April 2016, which aims to demonstrate proof of concept for ultra-fast light-driven “nanocraft”, laying the foundation for the first launch to Alpha Centauri within a generation.

Detecting a habitable planet is an enormous challenge due to the brightness of the planetary system’s host star, which tends to overwhelm the relatively dim planets. One way to make this easier is to observe in the mid-infrared wavelength range, where the thermal glow from an orbiting planet greatly reduces the brightness gap between it and its host star. But even in the mid-infrared, the star remains millions of times brighter than the planets to be detected, which calls for a dedicated technique to reduce the blinding stellar light.

The existing mid-infrared instrument VISIR on the VLT will provide such performance if it were enhanced to greatly improve the image quality using adaptive optics, and adapted to employ a technique called coronagraphy to reduce the stellar light and thereby reveal the possible signal of potential terrestrial planets. Breakthrough Initiatives will pay for a large fraction of the necessary technologies and development costs for such an experiment, and ESO will provide the required observing capabilities and time.

The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2 m across, which are generally used separately but can be used together to achieve very high angular resolution. The four separate optical telescopes are known as Antu, Kueyen, Melipal and Yepun, which are all words for astronomical objects in the Mapuche language. The telescopes form an array which is complemented by four movable Auxiliary Telescopes (ATs) of 1.8 m aperture.

The VLT operates at visible and infrared wavelengths. Each individual telescope can detect objects roughly four billion times fainter than can be detected with the naked eye, and when all the telescopes are combined, the facility can achieve an angular resolution of about 0.001 arc-second. This is equivalent to roughly 2 meters resolution at the distance of the Moon. In single telescope mode of operation angular resolution is about 0.05 arc-second

The European Southern Observatory (ESO) has announced an agreement with the billionaire-backed Breakthrough Initiatives program to fund an upgrade to the Very Large Telescope (VLT) facility in Chile. In return, the telescope will train its sharper eyes on the recently discovered Proxima b, a rocky exoplanet of our nearest star system that may serve as a potential target for future probes.

Detecting dim planets next to bright stars has been likened to finding a firefly next to a lighthouse, so astronomers have to resort to all sorts of convoluted tricks. The VLT’s specialty is seeing in the dark.

The VISIR (VLT Imager and Spectrometer for mid-Infrared) instrument collects a kind of radiation given off by heat, invisible to the naked eye. Just as infrared goggles allow soldiers to see warm objects at night, VISIR lets the VLT see hot stars and warm planets against the coldness of space.

Looking at star systems in the infrared spectrum “greatly reduces the brightness gap” between planets and stars, but planets are still quite a bit cooler than their hosts, which remain millions of times brighter. As it stands now, despite being able to theoretically detect car headlights as far away as the moon, the VLT is not quite up to the challenge. Breakthrough thinks the answer is a new pair of sunglasses.

This technology, more properly called coronagraphy, is the practice of physically blocking out the lighthouse so the fireflies will stand out. Traditionally applied to the sun to aid observation of the corona, the sun’s outer atmosphere, astronomers have only recently started to apply the technique to attempt direct photography of exoplanets.

Under the terms of the agreement, Breakthrough Initiatives will pay for most of the upgrades, including adaptive optics to counter distortions of light passing through Earth’s atmosphere, and the ESO will provide telescope time to observe Alpha Centauri. The University of Liège (Belgium) and Uppsala University (Sweden) will work together to develop a new coronagraph.

The new hardware includes an instrument module contracted to Kampf Telescope Optics (KTO), Munich, which will host the wavefront sensor, and a novel detector calibration device. In addition, there are plans for a new coronagraph to be developed jointly by University of Liège (Belgium) and Uppsala University (Sweden).

Detecting and studying potentially habitable planets orbiting other stars will be one of the main scientific goals of the upcoming European Extremely Large Telescope (E-ELT). Although the increased size of the E-ELT will be essential to obtaining an image of a planet at larger distances in the Milky Way, the light collecting power of the VLT is just sufficient to image a planet around the nearest star, Alpha Centauri.

The developments for VISIR will also be beneficial for the future METIS instrument, to be mounted on the E-ELT, as the knowledge gained and proof of concept will be directly transferable.

The huge size of the E-ELT should allow METIS to detect and study exoplanets the size of Mars orbiting Alpha Centauri, if they exist, as well as other potentially habitable planets around other nearby stars.

The Breakthrough Initiatives are a program of scientific and technological exploration founded in 2015 by Internet investor and science philanthropist Yuri Milner to explore the Universe, seek scientific evidence of life beyond Earth, and encourage public debate from a planetary perspective.

Breakthrough Starshot is a $100 million research and engineering program aiming to demonstrate proof of concept for a new technology, enabling ultra-light unmanned space flight at 20% of the speed of light, and to lay the foundations for a flyby mission to Alpha Centauri within a generation.

SOURCES - Breakthrough Initiative, European space Organization, Wikipedia

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