The VOLS survey is granted 306 observing hours to study molecular cloud Orion A

16 December 2021

Credit: NRAO/AUI/NSF, Jeff Hellerman

  • The study will observe the northern region of the Orion A cloud molecular complex with the Very Large Array telescope to make a census of the star population.

  • The international team of astronomers is led by the IEEC researcher at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB) Gemma Busquet

  • Researchers Josep Miquel Girart, José María Torrelles and Bo Huang from the Institute of Space Sciences (ICE-CSIC) and other researchers from ICCUB participate in the study

A team of astronomers led by the researcher Gemma Busquet of the Institute of Cosmos Sciences (ICCUB-IEEC), have been granted 306 telescope hours for their observational project “VOLS: The VLA Orion A Large Survey”. This survey will observe the northern region of the molecular cloud Orion A using the Karl G. Jansky Very Large Array Telescope in New Mexico (USA) to build a census of the stellar population, characterize their radio emission and quantify their rates of mass loss (ejected from the star) and mass accretion (fallen into the star from the stellar disk).

The VOLS survey counts with 46 researchers around the globe, including the researchers from the Institut of Space Sciences (ICE-CSIC) Josep Miquel Girart, José María Torrellas and Bo Huang, and several ICCUB members.

The observations will focus on two radio frequency bands. This will be the first radio study to cover a large area of Orion A at subarcsecond resolution, improving the sensitivity by a factor of 20 compared to previous large-scale surveys in Orion.

The main goal of this survey is to study the evolution of young stellar objects (YSOs) and protostars (which are the earliest phases of the life of a star) to determine the properties of stars and planetary systems. The early stages of star and planet formation involve a balance between accretion and ejection of material in gravitational collapse. There is hence an underlying accretion-ejection connection that governs and keeps track of the protostellar evolution, crucial in determining the final properties of stars and their planetary systems.

In this context, both mass accretion rate and mass-loss rate are fundamental, albeit still uncertain, quantities in star formation. It is, therefore, logical to ask how these quantities evolve with time and, just as importantly, how they proceed in the same way across the entire mass spectrum.

The team proposes the VLA Large Program VOLS to investigate how these rates vary with protostellar evolution, and how they depend on the initial conditions (i.e., the environment) and on the mass of the star.

To answer these questions, the team will use the Very Large Array Telescope to observe the northern part of the molecular cloud Orion A, covering an area of approximately 0,5 deg2 (which is roughly four times the size of the moon in the sky). The motivation behind this choice is that Orion A is the nearest star-forming complex containing a broad range of environments populated by protostars and YSOs with different masses and evolutionary stages, representing a testbed for star formation theories.

Together with previous datasets, such as Gaia DR3, VOLS will provide the ultimate correlation between the characteristics of the radio emission from YSOs and their properties. This project is crucial for the next generation of centimetric interferometers such as the Square Kilometer Array (SKA) or the Next-generation Very Large Array (ngVLA), since it will provide a radio template of YSOs and protostars.

Press release in collaboration with ICCUB and IEEC Communication Offices.



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