Stellar interferometry with a K-band integrated optics beam combiner instrument at the CHARA Array - I. First on-sky fringes for CHARIOT
Abstract
We present the instrument description and the first on-sky observations for the new CHara ARray Integrated Optics Testbench (CHARIOT) at the CHARA Array. CHARIOT is a 2-telescope proof-of-concept instrument that utilises a fibre-connectorised beam combiner fabricated by ultrafast laser-inscription in Infrasil quartz glass, which presents low-OH contamination and high transparency over the whole K-band. With its fibre-connected architecture, CHARIOT is designed as a plug-and-play testbed instrument to test and validate fibred astrophotonic components on-sky. At this point, CHARIOT is able to measure raw fringe squared visibilities with a sub-1% precision for stars with K-mag<2. Under poor to moderate seeing conditions, the current limiting magnitude for fringe detection is K-mag = 5.212 (HD210824). These results demonstrate that CHARIOT's performance is already comparable to the former JouFLU instrument. With additional improvements, the limiting magnitude could be extended and the precision for fainter stars improved. The successful on-sky demonstration paves the way for a new high precision K-band beam combiner instrument at the CHARA array.
Versions
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BibTeX
@misc{dinkelaker2026stellar,
title = {{Stellar interferometry with a K-band integrated optics beam combiner instrument at the CHARA Array - I. First on-sky fringes for CHARIOT}},
author = {Aline N. Dinkelaker and Kévin Barjot and Nic Scott and Aurélien Benoît and Narsireddy Anugu and Alyssa V. Mayer and Jacopo Siliprandi and Robert R. Thomson and Kalaga Madhav and Gail Schaefer and Lucas Labadie},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.35194},
eprint = {2609.35194},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.35194},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Stellar interferometry with a K-band integrated optics beam combiner instrument at the CHARA Array - I. First on-sky fringes for CHARIOT
AU - Aline N. Dinkelaker
AU - Kévin Barjot
AU - Nic Scott
AU - Aurélien Benoît
AU - Narsireddy Anugu
AU - Alyssa V. Mayer
AU - Jacopo Siliprandi
AU - Robert R. Thomson
AU - Kalaga Madhav
AU - Gail Schaefer
AU - Lucas Labadie
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.35194
UR - https://arxiv.org/abs/2609.35194
AB - We present the instrument description and the first on-sky observations for the new CHara ARray Integrated Optics Testbench (CHARIOT) at the CHARA Array. CHARIOT is a 2-telescope proof-of-concept instrument that utilises a fibre-connectorised beam combiner fabricated by ultrafast laser-inscription in Infrasil quartz glass, which presents low-OH contamination and high transparency over the whole K-band. With its fibre-connected architecture, CHARIOT is designed as a plug-and-play testbed instrument to test and validate fibred astrophotonic components on-sky. At this point, CHARIOT is able to measure raw fringe squared visibilities with a sub-1% precision for stars with K-mag<2. Under poor to moderate seeing conditions, the current limiting magnitude for fringe detection is K-mag = 5.212 (HD210824). These results demonstrate that CHARIOT's performance is already comparable to the former JouFLU instrument. With additional improvements, the limiting magnitude could be extended and the precision for fainter stars improved. The successful on-sky demonstration paves the way for a new high precision K-band beam combiner instrument at the CHARA array.
ER -