Portable adaptive optics for exoplanet imaging

• Published in: Research in astronomy and astrophysics Vol. 21; no. 4; pp. 82 - 40
• Main Authors: Zhu, Yong-Tian, Dou, Jiang-Pei, Zhang, Xi, Zhao, Gang, Guo, Jing, Infante, Leopoldo
• Format: Journal Article
• Language: English
• Published: Beijing National Astronomical Observatories, CAS and IOP Publishing Ltd 01.05.2021; IOP Publishing; School of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049,China%National Astronomical Observatories / Nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,Nanjing 210042,China; Institute of Astrophysics,Pontificia Universidad Católica de Chile,Av.Vic Mackenna 4860,Santiago,Chile; Key Laboratory of Astronomical Optics & Technology,Nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,Nanjing 210042,China; Núcleo de Astronomía de la Facultad de Ingeniería y Ciencias,Universidad Diego Portales,Manuel Rodríguez Sur 415,Santiago,Chile; National Astronomical Observatories / Nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,Nanjing 210042,China; Key Laboratory of Astronomical Optics & Technology,Nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,Nanjing 210042,China%Las Campanas Observatory,Observatories of the Carnegie Institution of Washington,Colina E1 Pino S/N Casilla 601 La Serena,Chile
• Subjects: Adaptive control; Adaptive optics; Algorithms; Astrometry; Extrasolar planets; Image rotation; instrumentation: adaptive optics; instrumentation: high angular resolution; methods: observational; Optics; Portable equipment; stars: imaging; Strehl ratio; Subtraction; techniques: image processing; Telescopes; stars:imaging; instrumentation:high angular resolution; instrumentation:adaptive optics; techniques:image processing; methods:observational
• ISSN: 1674-4527
• DOI: 10.1088/1674-4527/21/4/82

Abstract The portable adaptive optics (PAO) device is a low-cost and compact system, designed for 4- meter class telescopes that have no adaptive optics (AO) system, because of the physical space limitation at the Nasmyth or Cassegrain focus and the historically high cost of conventional AO. The initial scientific observations of the PAO are focused on the direct imaging of exoplanets and sub-stellar companions. This paper discusses the concept of PAO and the associated high-contrast imaging performance in our recent observational runs. PAO deliver a Strehl ratio better than 60% in H band under median seeing conditions of 1″. Combined with our dedicated image rotation and subtraction (IRS) technique and the optimized IRS (O-IRS) algorithm, the averaged contrast ratio for a 5 ≤ V mag ≤ 9 primary star is 1.3 × 10 −5 and 3.3 × 10 −6 at angular distance of 0.36″ with exposure time of 7 minutes and 2 hours, respectively. PAO has successfully revealed the known exoplanet of κ And b in our recent observation with the 3.5-meter ARC telescope at Apache Point Observatory. We have performed the associated astrometry and photometry analysis of the recovered κ And b planet, which gives a projected separation of 0.984″ ± 0.05″, a position angle of 51.1° ± 0.5° and a mass of 10.15 − 1.255 + 2.19 M Jup . These results demonstrate that PAO can be used for direct imaging of exoplanets with medium-sized telescopes.