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Precision Millimeter Astrometry of the α Centauri AB System

Akeson, Rachel and Beichman, Charles and Kervella, Pierre and Fomalont, Edward and Benedict, G. Fritz (2021) Precision Millimeter Astrometry of the α Centauri AB System. Astronomical Journal, 162 (1). Art. No. 14. ISSN 0004-6256. doi:10.3847/1538-3881/abfaff.

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Alpha Centauri A is the closest solar-type star to the Sun and offers the best opportunity to find and ultimately to characterize an Earth-sized planet located in its habitable zone. Here, we describe initial results from an Atacama Large Millimeter/submillimeter Array (ALMA) program to search for planets in the α Cen AB system using differential astrometry at millimeter wavelengths. Our initial results include new absolute astrometric measurements of the proper motion, orbital motion and parallax of the α Cen system. These lead to an improved knowledge of the physical properties of both α Cen A and B. Our estimates of ALMA's relative astrometric precision suggest that we will ultimately be sensitive to planets of a few tens of Earth mass in orbits from 1 to 3 au, where stable orbits are thought to exist.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Akeson, Rachel0000-0001-9674-1564
Beichman, Charles0000-0002-5627-5471
Kervella, Pierre0000-0003-0626-1749
Fomalont, Edward0000-0002-9036-2747
Benedict, G. Fritz0000-0003-2852-3279
Additional Information:© 2021 The American Astronomical Society. Received 2020 October 26; revised 2021 April 20; accepted 2021 April 21; published 2021 June 14. This paper makes use of the following ALMA data: ADS/JAO.ALMA #2018.1.00557.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Some of the research described in this publication was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. G.F.B. thanks McDonald Observatory for extending a Research Fellow position, allowing continued possession of an office and computing equipment. We thank the referees for a careful reading of the paper and for making many useful suggestions to clarify the material. Facilities: ALMA - Atacama Large Millimeter Array, ESO:3.6 m(HARPS). - Software: CASA (McMullin et al. 2007), astropy (Astropy Collaboration et al. 2013, 2018).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
McDonald ObservatoryUNSPECIFIED
Subject Keywords:Fundamental parameters of stars; Main sequence stars; Radio astrometry; Astrometric binary stars
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Fundamental parameters of stars (555); Main sequence stars (1000); Radio astrometry (1337); Astrometric binary stars (79)
Record Number:CaltechAUTHORS:20210623-175249522
Persistent URL:
Official Citation:Rachel Akeson et al 2021 AJ 162 14
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109557
Deposited By: Tony Diaz
Deposited On:23 Jun 2021 19:40
Last Modified:23 Jun 2021 19:40

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