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http://hdl.handle.net/20.500.12386/27427
Title: | Evidence for orbital motion of CW Leonis from ground-based astrometry | Authors: | SOZZETTI, Alessandro SMART, Richard Laurence DRIMMEL, Ronald Giacobbe, P. LATTANZI, Mario Gilberto |
Issue Date: | 2017 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 471 | Issue: | 1 | First Page: | L1 | Abstract: | Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations indicate that CW Leo, the closest carbon-rich asymptotic giant branch star to Sun, might have a low-mass stellar companion. We present archival ground-based astrometric measurements of CW Leo obtained within the context of the Torino Parallax Program and with >6 yr (1995-2001) of time baseline. The residuals to a single-star solution show significant curvature, and they are strongly correlated with the well-known I-band photometric variations due to stellar pulsations. We describe successfully the astrometry of CW Leo with a variability-induced motion (VIM) + acceleration model. We obtain proper motion and parallax of the centre-of-mass of the binary, the former in fair agreement with recent estimates, the latter at the near end of the range of inferred distances based on indirect methods. The VIM + acceleration model results allow us to derive a companion mass in agreement with that inferred by ALMA, they point towards a somewhat longer period than implied by ALMA, but are not compatible with much longer period estimates. These data will constitute a fundamental contribution towards the full understanding of the orbital architecture of the system when combined with Gaia astrometry, providing an ∼25 yr time baseline. | URI: | http://hdl.handle.net/20.500.12386/27427 | URL: | https://academic.oup.com/mnrasl/article-abstract/471/1/L1/3860091?redirectedFrom=fulltext | ISSN: | 0035-8711 | DOI: | 10.1093/mnrasl/slx082 | Bibcode ADS: | 2017MNRAS.471L...1S | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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