The gas streamer G1–2–3 in the Galactic center

¹ Max Planck Institute for extraterrestrial Physics, Giessenbachstraße 1, 85748 Garching, Germany
² Departments of Physics and Astronomy, Le Conte Hall, University of California, Berkeley, CA 94720, USA
³ Technical University of Munich, 85747 Garching, Germany
⁴ Universidad Adolfo Ibañez, Av. Padre Hurtado 750, Viña del Mar, Chile
⁵ Max Planck Institute for Astrophysics, Karl-Schwarzschild-Straße 1, 85748 Garching, Germany
⁶ University Observatory Munich, Scheinerstraße 1, 81679 Munich, Germany
⁷ Racah Institute for Physics, The Hebrew University, Jerusalem 91904, Israel
⁸ Department of Physics and Astronomy, Bartol Research Institute, University of Delaware, Newark, DE 19716, USA
⁹ Millennium Nucleus on Transversal Research and Technology to Explore Supermassive Black Holes (TITANS), Chile
¹⁰ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5., 50125, Firenze, Italy
¹¹ INAF – Osservatorio Astronomico d’Abruzzo, Via Mentore Maggini, 64100 Teramo, Italy
¹² INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
¹³ STFC UK ATC, Royal Observatory Edinburgh, Blackford Hill. Edinburgh EH9 3HJ, UK
¹⁴ ETH Zurich, Institute of Particle Physics and Astrophysics, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
¹⁵ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
¹⁶ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany

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

Received: 4 June 2025
Accepted: 16 January 2026

Abstract

The black hole in the Galactic center, Sgr A*, is prototypical of ultra-low-fed galactic nuclei. The discovery of a handful of gas clumps with masses on the order of a few Earth masses in its immediate vicinity provides a gas reservoir sufficient to power Sgr A*. In particular, the gas cloud G2 is of interest due to its extreme orbit, on which it passed at a pericenter distance of around 100 AU and notably lost kinetic energy during the fly-by due to interaction with the black hole accretion flow. Thirteen years prior to G2, a similar gas cloud called G1, passed Sgr A* on a similar orbit. The origin of G2 remained a topic of discussion, with models including a central (stellar) source still proposed as alternatives to pure gas clouds. Here, we report the orbit of a third gas clump moving along (nearly) the same orbital trace. Since the probability of finding three stars on such similar orbits is very low, this strongly argues against stellar-based source models. Instead, we show that the gas streamer G1–2–3 plausibly originates from the stellar wind of the massive binary star IRS 16SW. This claim is substantiated by the fact that the small differences between the three orbits – the orientations of the orbital ellipses in their common plane as a function of time – are consistent with the orbital motion of IRS 16SW.