Large Interferometer For Exoplanets (LIFE)

Abstract

Aims. Optical interferometry from space for the purpose of detecting and characterising exoplanets is seeing a revival, specifically from missions such as the proposed Large Interferometer For Exoplanets (LIFE). A default assumption since the design studies of Darwin and TPF-I has been that the Emma X-array configuration is the optimal architecture for this goal. Here, we examine whether new advances in the field of nulling interferometry, such as the concept of kernel-nulling, challenge this assumption. Methods. We develop a tool designed to derive the photon-limited signal-to-noise ratio of a large sample of simulated planets for different architecture configurations and beam combination schemes. We simulate four basic configurations: the double Bracewell/Xarray, and three kernel-nullers with three, four, and five telescopes respectively. Results. We find that a configuration of five telescopes in a pentagonal shape, using a five-aperture kernel-nulling scheme, outperforms the X-array design in both search (finding more planets) and characterisation (obtaining better signal, faster) when the total collecting area is conserved. This is especially the case when trying to detect Earth twins (temperate, rocky planets in the habitable zone (HZ)), showing a 23% yield increase over the X-array. On average, we find that a five-telescope design receives 1.2 times more signal than the X-array design. Conclusions. With the results of this simulation, we conclude that the Emma X-array configuration may not be the best choice of architecture for the upcoming LIFE mission, and that a five-telescope design utilising kernel-nulling concepts will likely provide better scientific return for the same collecting area, provided that technical solutions for the required achromatic phase shifts can be implemented.

Large Interferometer For Exoplanets (LIFE)

“…The middle two nulled rows of this matrix is equivalent to the middle two rows of the transfer matrix of the traditional X-array beam combiner found in equation 6 of LIFE4, with an alternative numbering of the telescopes. Hence this beam combiner could be used to produce the properties of the X-array as described in previous works (Quanz et al 2022;Hansen et al 2022). The benefit of this combination scheme is two-fold: there is an additional nulled output (albeit not a contribution to the kernel-null), and the same redundancy benefits as the Kernel-5 nuller apply.…”

Advances in Optical/Infrared Interferometry

“…Due to the importance for nulling to the future of exoplanet studies, theoretical and experimental work remains active. We point the reader to recent explorations of the optimal nulling architectures (e.g., Guyon et al 2013, Hansen et al 2022, ways to combine nulling with closure phases (Lacour et al 2014b), nulling within IO (e.g., Hsiao et al 2010, Errmann et al 2015, Martinod et al 2021, and development of better IR-friendly materials for IO, such as lithium niobate (Hsiao et al 2009) and chalcogenides (Kenchington Goldsmith et al 2017). There is a new exoplanet-focused instrument, VLTI/NOTT (Nulling Observations of exoplaneTs and dusT; Defrère et al 2018), under construction that will push nulling down to the L band (3.8 µm) for the first time, and there is an active consortium proposing a space-nulling interferometer, the Large Interferometer for Exoplanets (LIFE; Quanz et al 2022).…”

Imaging of exocomets with infrared interferometry

“…This feasibility study concerns imaging of exocomets with LIFE. The design of LIFE is under active evaluation (e.g., Hansen et al 2022), but here we will use the same reference case design of LIFE as in Quanz et al (2022). The design involves four telescope units, which as a baseline in this study will be assumed to each be 2 m in diameter.…”