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Astrometric Detection of a Low-Mass Companion Orbiting the Star AB Doradus


Guirado, JC and Reynolds, JE and Lestrade, JF and Preston, RA and Jauncey, DL and Jones, DL and Tzioumis, AK and Ferris, RH and King, EA and Lovell, JEJ and McCulloch, PM and Johnston, KJ and Kingham, KA and Martin, JO and White, GL and Jones, PA and Arenou, F and Froeschle, M and Kovalevsky, J and Martin, C and Lindegren, L and Soderhjelm, S, Astrometric Detection of a Low-Mass Companion Orbiting the Star AB Doradus, The Astrophysical Journal, 490, (2) pp. 835-839. ISSN 0004-637X (1997) [Refereed Article]

DOI: doi:10.1086/304920


We report submilliarcsecond-precise astrometric measurements for the late-type star AB Doradus via a combination of VLBI (very long baseline interferometry) and HIPPARCOS data. Our astrometric analysis results in the precise determination of the kinematics of this star, which reveals an orbital motion readily explained as caused by gravitational interaction with a low-mass companion. From the portion of the reflex orbit covered by our data and using a revised mass of the primary star (0.76 M ⊙) derived from our new value of the parallax (66.3 mas < π < 67.2 mas), we find the dynamical mass of the newly discovered companion to be between 0.08 and 0.11 M ⊙. If accurate photometric information can be obtained for the low-mass companion, our precise mass estimate could serve as an accurate calibration point for different theoretical evolutionary models of low-mass objects. This represents the first detection of a low-mass stellar companion using VLBI, a technique that will become an important tool in future searches for planets and brown dwarfs orbiting other stars. © 1997. The American Astronomical Society. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:King, EA (Dr King)
UTAS Author:Lovell, JEJ (Dr Jim Lovell)
UTAS Author:McCulloch, PM (Professor Peter McCulloch)
ID Code:12460
Year Published:1997
Web of Science® Times Cited:61
Deposited By:Physics
Deposited On:1997-08-01
Last Modified:2011-08-15

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