The discrepancy between dynamical and theoretical mass in the triplet-system 2MASS J10364483+1521394

Autor(en)

Per Calissendorff, Markus Janson, Rainer Köhler, Stephen Durkan, Stefan Hippler, Xiaolin Dai, Wolfgang Brandner, Joshua Schlieder, Thomas Henning

Abstrakt

We combine new Lucky Imaging astrometry from New Technology Telescope/AstraLux Sur with already published astrometry from the AstraLux Large M-dwarf Multiplicity Survey to compute orbital elements and individual masses of the 2MASS J10364483+1521394 triple system belonging to the Ursa-Major moving group. The system consists of one primary low-mass M-dwarf orbited by two less massive companions, for which we determine a combined dynamical mass of M

_{B + C} = 0.48 ± 0.14 M

_⊙. We show from the companions' relative motions that they are of equal mass (with a mass ratio of 1.00 ± 0.03), thus 0.24 ± 0.07 M

_⊙ individually, with a separation of 3.2 ± 0.3 AU, and we conclude that these masses are significantly higher (30%) than what is predicted by theoretical stellar evolutionary models. The biggest uncertainty remains the distance to the system, here adopted as 20.1 ± 2.0 pc based on trigonometric parallax, whose ambiguity has a major impact on the result. With the new observational data we are able to conclude that the orbital period of the BC pair is 8.41

^+0.04

_-0.02yr.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Stockholm University, Leopold-Franzens-Universität Innsbruck, Queen's University Belfast, Max-Planck-Institut für Astronomie, National Aeronautics & Space Administration (NASA)

Journal

Astronomy & Astrophysics

Band

604

Anzahl der Seiten

9

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/201730725

Publikationsdatum

08-2017

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/03168eaf-3fd6-4181-9ba4-b178f5ceca01