Astro-comb explained

An astro-comb is a type of frequency comb used in observational astronomy to increase the accuracy of wavelength calibration in spectrographs.[1] [2] The increased accuracy reduces systematic errors and enhances detection of small variations in stellar radial velocities caused by smaller orbiting exoplanets (e.g. Earth-mass planets), among other applications.[3] [4] Astro-combs are distinguished from conventional frequency combs by their focus on high repetition frequencies (with mode spacings of ≥10 GHz).[5]

A green astro-comb was installed in January 2013 in the high accuracy radial velocity planet searcher in the northern hemisphere (HARPS-N) spectrograph at the Telescopio Nazionale Galileo on the Canary Islands.[6] The device was developed by a team led by Chih-Hao Li of Harvard University. This astro-comb uses a pulsed laser to filter starlight before feeding the signal into a spectrograph. As of December 2016, it is gathering data from Venus to demonstrate its ability to discover exoplanets.[7]

See also

References

  1. Web site: Frequency Combs to Measure Cosmic Velocities . Astrocombs . LMU University of Munich . 25 January 2022 . 2015-03-08.
  2. News: NIST 'Astrocomb' Opens New Horizons for Planet-Hunting Telescope . 25 January 2022 . National Institute of Standards and Technology (NIST) . National Institute of Standards and Technology (NIST) . February 19, 2019.
  3. Chae . Eunmi . Kambe . Eiji . Motohara . Kentaro . Izumiura . Hideyuki . Doi . Mamoru . Yoshioka . Kosuke . Compact green Ti:sapphire astro-comb with a 43 GHz repetition frequency . Journal of the Optical Society of America B . 1 July 2021 . 38 . 7 . A1 . 10.1364/JOSAB.419078. 2101.05926 . 2021JOSAB..38A...1C . 231627499 .
  4. Web site: Astro Combs . Astro Combs . Harvard & Smithsonian . 25 January 2022 . 2017-03-03.
  5. Ravi . Aakash . Phillips . David F. . Beck . Matthias . Martin . Leopoldo L. . Cecconi . Massimo . Ghedina . Adriano . Molinari . Emilio . Bartels . Albrecht . Sasselov . Dimitar . Szentgyorgyi . Andrew . Walsworth . Ronald L. . Astro-comb calibrator and spectrograph characterization using a turn-key laser frequency comb . Journal of Astronomical Telescopes, Instruments, and Systems . 17 November 2017 . 3 . 4 . 045003 . 10.1117/1.JATIS.3.4.045003. 1705.07192 . 2017JATIS...3d5003R . 13676771 .
  6. Web site: A green astro-comb to search for Earth-like exoplanets. spie.org. 2016-12-01.
  7. Web site: TNG :: TNG, HARPS-N and Astro Comb ready to characterize the first earth twin. www.tng.iac.es. 2016-12-01.

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