Dynamical masses of young stellar objects with the VLBA: DYNAMO-VLBA

Trigonometric parallaxes and proper motions of YSOs in Orion

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
² Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Morelia 58089, Mexico
³ Departamento de Astronomía, Universidad de Guanajuato, Apartado Postal 144, 36000 Guanajuato, Mexico
⁴ Black Hole Initiative at Harvard University, 20 Garden Street, Cambridge, MA 02138, USA
⁵ David Rockefeller Center for Latin American Studies, Harvard University, 1730 Cambridge Street, Cambridge, MA 02138, USA
⁶ Department of Physics and Astronomy, University of North Florida, 1 UNF Dr., Jacksonville, FL 32224, USA
⁷ Instituto Nacional de Astrofísica, Óptica y Electrónica, Apartado Postal 51 y 216, 72000 Puebla, Mexico
⁸ Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão, 1226, Cidade Universitária, 05508-090 São Paulo-SP, Brazil
⁹ National Radio Astronomy Observatory, Domenici Science Operations Center, 1003 Lopezville Road, Socorro, NM 87801, USA
¹⁰ Departament de Física Quàntica i Astrofísica (FQA), Universitat de Barcelona (UB), c/ Martí i Franquès 1, 08028 Barcelona, Catalunya, Spain
¹¹ Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (UB), c/ Martí i Franquès 1, 08028 Barcelona, Catalunya, Spain
¹² Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
¹³ Center for Astrophysics | Harvard & Smithsonian, 60 Garden St, MS 72 Cambridge, MA 02138, USA
¹⁴ Facultad de Ingeniería, Universidad Autónoma de Yucatán, Avenida Industrias No Contaminantes por Anillo Periférico Norte s/n, 97302 Mérida, Yucatán, Mexico

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 18 November 2025
Accepted: 10 February 2026

Abstract

We present results from a multi-epoch Very Long Baseline Array (VLBA) survey of compact radio sources in the Orion complex, conducted within both the DYNAMO–VLBA and GOBELINS projects. We detected 216 compact radio sources, of which 58 yielded reliable multi-epoch astrometric solutions. For these sources, we derived trigonometric parallaxes and proper motions with typical precisions of about 0.05 mas and 0.10 mas yr⁻¹, respectively. The measured parallaxes range between 2.26 and 2.65 mas, corresponding to distances of 380–440 pc, and delineate the depth of the Orion star-forming complex. We determined mean distances of 405 ± 16 pc for NGC 2068, 403 ± 5 pc for NGC 2024, 407 ± 12 pc for the σ Orionis region, 388.5 ± 1.7 pc for the Orion Nebula Cluster, and 438 ± 12 pc for L1641. A comparison with Gaia DR3 astrometry for 28 common sources revealed negligible mean parallax offsets (Δϖ= − 0.02 ± 0.01 mas) and small systematic differences in proper motions (∼0.07 mas yr⁻¹), likely due to the residual rotation of the Gaia reference frame. Our results demonstrate the capability of high-precision radio astrometry to map embedded stellar populations and to provide an independent calibration of the Gaia reference system in obscured regions.