Star formation triggered by SN explosions: an application to the stellar association of   Pictoris

Abstract

In the present study, considering the physical conditions that are relevant in interactions between supernova remnants (SNRs) and dense molecular clouds for triggering star formation we have built a diagram of SNR radius versus cloud density in which the constraints above delineate a shaded zone where star formation is allowed. We have also performed fully 3D radiatively cooling numerical simulations of the impact between SNRs and clouds under different initial conditions in order to follow the initial steps of these interactions. We determine the conditions that may lead either to cloud collapse and star formation or to complete cloud destruction and find that the numerical results are consistent with those of the SNR–cloud density diagram. Finally, we have applied the results above to the β Pictoris stellar association which is composed of low‐mass post‐T Tauri stars with an age of 11 Myr. It has been recently suggested that its formation could have been triggered by the shock wave produced by an SN explosion localized at a distance of about 62 pc that may have occurred either in the Lower Centaurus Crux or in the Upper Centaurus Lupus which are both nearby older subgroups of that association (Ortega and co‐workers). Using the results of the analysis above we have shown that the suggested origin for the young association at the proposed distance is plausible only for a very restricted range of initial conditions for the parent molecular cloud, that is, a cloud with a radius of the order of 10 pc and density of the order of 20 cm−3 and a temperature of the order of 50–100 K.

A multiwavelength study of the star forming region IRAS 18544+0112

“…On the other hand, shockwaves from expanding windand/or supernova-driven superbubbles can also trigger cloud collapse and star formation, but at larger scales. Numerical studies (Vanhala & Cameron 1998;Melioli et al 2006) demonstrated that the effect caused by a passing shockwave mainly depends on the shock-type: close to the supernova remnant (SNR) the shockwave disrupts the ambient molecular clouds and thus terminates the star formation process; however, a little further away from the SNR the shock velocity decreases, and cloud collapse is possible if the right circumstances were given.…”

Analytic solutions to the accretion of a rotating finite cloud towards a central object - I. Newtonian approach

“…In this scenario, Ulrich's model is not applicable. There are well‐known mechanisms for the triggering, namely stellar ejecta from winds (Foster & Boss 1996) or supernova shells (Melioli et al 2006) as well as the ionizing radiation from a star, or a collection of stars, that produces an ionization shock front (Bertoldi 1989; Esquivel & Raga 2007). Each of these mechanisms sets particular boundary conditions for the collapse of the cloud to form a star.…”

The Supershell–Molecular Cloud Connection: Large-Scale Stellar Feedback and the Formation of the Molecular ISM

“…Indeed, for moderate shock velocities appropriate to supershell systems, star formation may be triggered readily for a range of molecular cloud properties (e.g. Vanhala & Cameron 1998;Melioli et al 2006;Leão et al 2009). These considerations are important in interpreting observations of supershell-associated molecular gas and stars.…”