KALYPSO Project Description

High-mass stars are important components in the ecology of the interstellar medium (ISM) and the evolution of galaxies. They profoundly change the chemical and physical composition, and the energy budget, of the ISM. When young they disrupt parent molecular clouds, driving powerful outflows and emitting enormous UV fluxes that ionize HII regions. When old they go supernova and enrich the ISM with heavy elements, thereby influencing chemical and thermodynamic processes, and planting seed material from which planets can ultimately form.

However, there is no general theory of high-mass star formation because the balance of forces (e.g., magnetic) that affect material around massive young stellar objects (YSOs) and protostars has been difficult to infer reliably from observations (due largely to large distances, high extinction, clustering, and crowding). The goal of the project is to directly map and track the 3-D dynamics of gas around a massive, deeply embedded YSO in Orion-KL, at radii of 10 to 1000 AU, where outflow is launched from the accretion disk. This has never before been done. It is currently possible for just one known YSO, the target of our study, and lessons learned in this case will inform interpretation of data for most other massive YSOs. We will concentrate on three key questions: (i) what is the accretion disk structure 10 AU from a massive YSO; (ii) what is the outflow structure 10-1000 AU from a massive YSO; and (iii) what mechanisms shape and drive the disks and outflows - specifically, are magnetic fields important?

Kalypso Group Publications

The Most Detailed Picture Yet of an Embedded High-mass YSO, Greenhill et al., 2003 Proc IAU Symp 221, ASP
High Angular Resolution Mid-infrared Imaging of Young Stars in Orion BN/KL, Greenhill et al. 2004, Ap.J. 605 L57-L60
A Documentary of High-Mass Star Formation: Probing the Dynamical Evolution of Orion Source I on 10-100~AU Scales using SiO Masers, Matthews et al. 2008, Proc. IAU Symposium 242, ed. J. M. Chapman and W. A. Baan, p. 130
Disks, Young Stars, and Radio Waves: the Quest for Forming Planetary Systems, C. J. Chandler and D. S. Shepherd, 2008, to appear in the proceedings of the NRAO 50th Anniversary Science Symposium "Frontiers of Astrophysics", ASP Conf. Series, in press

Publications of Interest Involving Kalypso Group Members

Sub-arcsecond sub-mm continuum observations of Orion-KL, Beuther et al. 2004, Ap.J. 616 L31-L34
Submm line imaging of Orion-KL with the Submillimeter Array, Beuther et al. 2005, Ap.J. 632 355-370

Contact Us	KALYPSO Project Description High-mass stars are important components in the ecology of the interstellar medium (ISM) and the evolution of galaxies. They profoundly change the chemical and physical composition, and the energy budget, of the ISM. When young they disrupt parent molecular clouds, driving powerful outflows and emitting enormous UV fluxes that ionize HII regions. When old they go supernova and enrich the ISM with heavy elements, thereby influencing chemical and thermodynamic processes, and planting seed material from which planets can ultimately form. However, there is no general theory of high-mass star formation because the balance of forces (e.g., magnetic) that affect material around massive young stellar objects (YSOs) and protostars has been difficult to infer reliably from observations (due largely to large distances, high extinction, clustering, and crowding). The goal of the project is to directly map and track the 3-D dynamics of gas around a massive, deeply embedded YSO in Orion-KL, at radii of 10 to 1000 AU, where outflow is launched from the accretion disk. This has never before been done. It is currently possible for just one known YSO, the target of our study, and lessons learned in this case will inform interpretation of data for most other massive YSOs. We will concentrate on three key questions: (i) what is the accretion disk structure 10 AU from a massive YSO; (ii) what is the outflow structure 10-1000 AU from a massive YSO; and (iii) what mechanisms shape and drive the disks and outflows - specifically, are magnetic fields important? Kalypso Group Publications The Most Detailed Picture Yet of an Embedded High-mass YSO, Greenhill et al., 2003 Proc IAU Symp 221, ASP High Angular Resolution Mid-infrared Imaging of Young Stars in Orion BN/KL, Greenhill et al. 2004, Ap.J. 605 L57-L60 A Documentary of High-Mass Star Formation: Probing the Dynamical Evolution of Orion Source I on 10-100~AU Scales using SiO Masers, Matthews et al. 2008, Proc. IAU Symposium 242, ed. J. M. Chapman and W. A. Baan, p. 130 Disks, Young Stars, and Radio Waves: the Quest for Forming Planetary Systems, C. J. Chandler and D. S. Shepherd, 2008, to appear in the proceedings of the NRAO 50th Anniversary Science Symposium "Frontiers of Astrophysics", ASP Conf. Series, in press Publications of Interest Involving Kalypso Group Members Sub-arcsecond sub-mm continuum observations of Orion-KL, Beuther et al. 2004, Ap.J. 616 L31-L34 Submm line imaging of Orion-KL with the Submillimeter Array, Beuther et al. 2005, Ap.J. 632 355-370
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