Astronomy:Astro-comb
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
- ↑ "Frequency Combs to Measure Cosmic Velocities". LMU University of Munich. 2015-03-08. http://www2.mpq.mpg.de/~haensch/astro/combs.html.
- ↑ "NIST 'Astrocomb' Opens New Horizons for Planet-Hunting Telescope". National Institute of Standards and Technology (NIST). National Institute of Standards and Technology (NIST). February 19, 2019. https://www.nist.gov/news-events/news/2019/02/nist-astrocomb-opens-new-horizons-planet-hunting-telescope.
- ↑ Chae, Eunmi; Kambe, Eiji; Motohara, Kentaro; Izumiura, Hideyuki; Doi, Mamoru; Yoshioka, Kosuke (1 July 2021). "Compact green Ti:sapphire astro-comb with a 43 GHz repetition frequency". Journal of the Optical Society of America B 38 (7): A1. doi:10.1364/JOSAB.419078. Bibcode: 2021JOSAB..38A...1C.
- ↑ "Astro Combs". Harvard & Smithsonian. 2017-03-03. https://pweb.cfa.harvard.edu/research/topic/astro-combs.
- ↑ Ravi, Aakash; Phillips, David F.; Beck, Matthias; Martin, Leopoldo L.; Cecconi, Massimo; Ghedina, Adriano; Molinari, Emilio; Bartels, Albrecht et al. (17 November 2017). "Astro-comb calibrator and spectrograph characterization using a turn-key laser frequency comb". Journal of Astronomical Telescopes, Instruments, and Systems 3 (4): 045003. doi:10.1117/1.JATIS.3.4.045003. Bibcode: 2017JATIS...3d5003R.
- ↑ "A green astro-comb to search for Earth-like exoplanets". http://spie.org/newsroom/5730-a-green-astro-comb-to-search-for-earth-like-exoplanets#B1.
- ↑ "TNG :: TNG, HARPS-N and Astro Comb ready to characterize the first earth twin". http://www.tng.iac.es/news/2015/07/28/tng-harps-astrocomb/.
- New Approaches to Precision Astrophysical Spectroscopy The Walsworth Group, October 10, 2016. Accessed November 30, 2016.
- TNG, HARPS-N and Astro Comb ready to characterize the first earth twin Fundación Galileo Galilei - INAF Telescopio Nazionale Galileo, July 28, 2015. Accessed December 1, 2016
- A green astro-comb to search for Earth-like planets Chih-Hao Li, SPIE, January 29, 2015. Accessed November 30, 2016.
- 'Astro-comb' helps search for Goldilocks planet Physorg.com, April 2, 2008. Accessed April 2, 2008.
- Astro-combing for Planets Astro Biology Magazine, April 9, 2008. Accessed April 11, 2008.
- Pulses to Find Planets, (Archive of Pulses to Find Planets Astro Biology Magazine, May 11, 2008. Accessed May 15, 2008. Based on a National Institute of Standards and Technology news release.)
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