Space and Planetary Science; Mechanical Engineering; Astronomy and Astrophysics; Instrumentation; Control and Systems Engineering; Electronic, Optical and Magnetic Materials
Abstract :
[en] Asgard/NOTT (previously Hi-5) is a European Research Council (ERC)-funded project hosted at KU Leuven and a new visitor instrument for the Very Large Telescope Interferometer (VLTI). Its primary goal is to image the snow line region around young stars using nulling interferometry in the L-band (3.5 to 4.0)μm, where the contrast between exoplanets and their host stars is advantageous. The breakthrough is the use of a photonic beam combiner, which only recently allowed the required theoretical raw contrast of 10−3 in this spectral range. Nulling interferometry observations of exoplanets also require a high degree of balancing between the four pupils of the VLTI in terms of intensity, phase, and polarization. The injection into the beam combiner and the requirements of nulling interferometry are driving the design of the warm optics and the injection system. The optical design up to the beam combiner is presented. It offers a technical solution to efficiently couple the light from the VLTI into the beam combiner. During the coupling, the objective is to limit throughput losses to 5% of the best expected efficiency for the injection. To achieve this, a list of different loss sources is considered with their respective impact on the injection efficiency. Solutions are also proposed to meet the requirements on beam balancing for intensity, phase, and polarization. The different properties of the design are listed, including the optics used, their alignment and tolerances, and their impact on the instrumental performances in terms of throughput and null depth. The performance evaluation gives an expected throughput loss of less than <6.4% of the best efficiency for the injection and a null depth of ∼2.10−3, mainly from optical path delay errors outside the scope of this work.
Research Center/Unit :
CSL - Centre Spatial de Liège - ULiège
Precision for document type :
Review article
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Garreau, Germain; KU Leuven, Institute of Astronomy, Leuven, Belgium
Bigioli, Azzurra; KU Leuven, Institute of Astronomy, Leuven, Belgium
Laugier, Romain; KU Leuven, Institute of Astronomy, Leuven, Belgium
Raskin, Gert; KU Leuven, Institute of Astronomy, Leuven, Belgium
Morren, Johan; KU Leuven, Institute of Astronomy, Leuven, Belgium
Berger, Jean-Philippe; University of Grenoble Alpes/CNRS, IPAG, Grenoble, France
Dandumont, Colin ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR)
Goldsmith, Harry-Dean Kenchington; Australian National University, Research School of Astronomy and Astrophysics, Canberra, Australian Capital Territory, Australia
Gross, Simon; Macquarie University, School of Mathematical and Physical Sciences, MQ Photonics Research Centre, Macquarie Park, New South Wales, Australia
Ireland, Michael; Australian National University, Research School of Astronomy and Astrophysics, Canberra, Australian Capital Territory, Australia
Labadie, Lucas; Universität zu Köln, I. Physikalisches Institut, Köln, Germany
Loicq, Jerôme ; Université de Liège - ULiège > Centres généraux > CSL (Centre Spatial de Liège)
Madden, Stephen; Australian National University, Research School of Astronomy and Astrophysics, Canberra, Australian Capital Territory, Australia
Martin, Guillermo; University of Grenoble Alpes/CNRS, IPAG, Grenoble, France
Martinod, Marc-Antoine; KU Leuven, Institute of Astronomy, Leuven, Belgium
Mazzoli, Alexandra ; Université de Liège - ULiège > Centres généraux > CSL (Centre Spatial de Liège)
Sanny, Ahmed; Macquarie University, School of Mathematical and Physical Sciences, MQ Photonics Research Centre, Macquarie Park, New South Wales, Australia
Shao, Hancheng; Australian National University, Research School of Astronomy and Astrophysics, Canberra, Australian Capital Territory, Australia
Yan, Kunlun; Australian National University, Research School of Astronomy and Astrophysics, Canberra, Australian Capital Territory, Australia
Defrere, Denis ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Planetary & Stellar systems Imaging Laboratory ; KU Leuven, Institute of Astronomy, Leuven, Belgium
ERC - European Research Council EU - European Union
Funding number :
GrantNo.CoG-866070; AwardNo.101004719
Funding text :
SCIFY has received funding from the European Research Council (ERC); Awardno.CoG866070 under the European Union’s Horizon 2020 research and innovation program. M-A.M. has
received funding from the European Union’s Horizon 2020 Research and Innovation Program; Award No.101004719.
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