Manipulando a luz das estrelas: ampliando as fronteiras da observação astronômica de estrelas duplas e seus companheiros com uma máscara de pupila adaptativa

Abstract

Much of our knowledge about double stars was obtained from the light from space that reaches our telescopes. The information provided by these electromagnetic waves is essential in the study of astrophysical objects. To improve the resources from this source, various instruments and techniques are under development to address the inherent challenges of capturing this light. Incident light in reflecting telescopes, for example, not only undergoes Fraunhofer diffraction but also scatters due to obstructions in their structure, blocking a portion of the light. If we wish to study objects near stars, such as exoplanets, companion stars, or circumstellar material, this scattering becomes a significant problem. In addition to technical issues, there are natural factors that degrade image quality, such as atmospheric turbulence. If this factor is mitigated, increasing the telescope’s aperture will be of little use, as the actual limitation of angular resolution for terrestrial telescopes is the atmosphere. Variations in the refractive index in turbulent atmospheres distort the wavefront, causing the point spread function (PSF) of short exposure to appear speckled. These speckles, in a long exposure regime, form a large halo around a central core, losing astrometric information. The formation of these speckles depends on the strength of turbulence, with worse seeing resulting in a more giant halo. An adaptive optics (AO) system can reduce the phase variation in a wavefront, increasing the energy fraction in a diffraction-limited core. However, no AO system is perfect, and there will always be residual phase variance. This work investigates a method to mitigate the effect of this variance using an adaptive pupil mask (APM). It can work alone or in conjunction with the AO system, reducing the PSF halo and thus improving the telescope’s performance in observing very close binary stars with a resolution below ½ arcseconds, a resolution where Gaia presents many spurious solutions. We also hope this system can improve image contrast, enabling the detection of exoplanets and faint companions in the close orbits of these stars. By actively blocking areas of the wavefront that are out of phase, the APM allows us to manipulate the PSF. We propose an alternative AO simulation, including the adaptive pupil mask, using the OOMAO simulation software (Mathlab). Additionally, we suggest replacing the deformable mirror with the APM composed of MEMS mirrors, a more affordable electronic device, given that piezoelectric deformable mirrors can be costly. This is aimed at providing a more economical, albeit limited, option for the optical project, considering the best cost-benefit ratio.