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

journal contribution
posted on 2023-05-16, 10:59 authored by Guirado, JC, Reynolds, JE, Lestrade, JF, Preston, RA, Jauncey, DL, Jones, DL, Tzioumis, AK, Ferris, RH, King, EA, James LovellJames Lovell, Peter McCullochPeter McCulloch, Johnston, KJ, Kingham, KA, Martin, JO, White, GL, Jones, PA, Arenou, F, Froeschle, M, Kovalevsky, J, Martin, C, Lindegren, L, Soderhjelm, S
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.

History

Publication title

The Astrophysical Journal

Volume

490

Pagination

835-839

ISSN

0004-637X

Department/School

School of Natural Sciences

Publisher

The American Astronomical Society

Place of publication

Chicago USA

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the physical sciences

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