Bipolar molecular outflow of the very low-mass star Par-Lup3-4

Evidence for scaled-down low-mass star formation^⋆

¹ European Southern Observatory, 3107 Alonso de Córdova, Santiago de Chile, Chile
e-mail: asantama@eso.org
² Instituto de Física y Astronomía, Universidad de Valparaíso, Av. Gran Bretaña 1111, 5030 Casilla, Valparaíso, Chile
³ Núcleo Milenio Formación Planetaria – NPF, Universidad de Valparaíso, Av. Gran Bretaña 1111, Valparaíso, Chile
⁴ Centro de Astrobiología (INTA-CSIC), ESAC campus, Camino bajo del Castillo s/n, Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain
⁵ National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA
⁶ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
⁷ Joint ALMA Observatory, 3107 Alonso de Córdova, Vitacura, Casilla, 19001 Santiago, Chile
⁸ CENTRA, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal
⁹ INAF/Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy

Received: 9 April 2020
Accepted: 23 May 2020

Abstract

Context. Very low-mass stars are known to have jets and outflows, which is indicative of a scaled-down version of low-mass star formation. However, only very few outflows in very low-mass sources are well characterized.

Aims. We characterize the bipolar molecular outflow of the very low-mass star Par-Lup3-4, a 0.12 M_⊙ object known to power an optical jet.

Methods. We observed Par-Lup3-4 with ALMA in Bands 6 and 7, detecting both the continuum and CO molecular gas. In particular, we studied three main emission lines: CO(2–1), CO(3–2), and ¹³CO(3–2).

Results. Our observations reveal for the first time the base of a bipolar molecular outflow in a very low-mass star, as well as a stream of material moving perpendicular to the primary outflow of this source. The primary outflow morphology is consistent with the previously determined jet orientation and disk inclination. The outflow mass is 9.5 × 10⁻⁷ M_⊙, with an outflow rate of 4.3 × 10⁻⁹ M_⊙ yr⁻¹. A new fitting to the spectral energy distribution suggests that Par-Lup3-4 may be a binary system.

Conclusions. We have characterized Par-Lup3-4 in detail, and its properties are consistent with those reported in other very low-mass sources. This source provides further evidence that very low-mass sources form as a scaled-down version of low-mass stars.