Two identical stars are moving in a circular orbit around one another with an orbital separation of 2 AU. The system lies 200 light-years from Earth. If we happen to view the orbit head-on, how large a telescope would we need to resolve the stars, assuming diffraction-limited optics at a wavelength of 2 µm?

Cas A SNR North Lobe Chandra ACIS image (M. Stage) region of spectrum-> 10* km/s (be sure to convert your answer to kilometers!) (Enter a positive value--if you get a negative answer ignore the minus sign.) 1000 100 Combine counts / Ang./ (0.964324 sq. arcsec) 10 1 0.1 Cas A Ms Spectrum from 4362.5 4458.5, region size 0.964324 sq. arcsec Silicon line werden der 5 10 20 Wavelength (Angstroms) The speed of the material ejected in a supernova can be measured by using the Doppler shift of the X-ray emission lines in its spectrum. The images above show real X ray data of the Cassiopeia A supernova remnant and a spectrum extracted from that data--you can see several emission lines including the silicon line near 6.6 angstroms (0.66 nm). If the emission line created by silicon normally has a wavelength of 0.6648 nm (nanometers), but is measured in the spectrum to have a wavelength of 0.6599 nm, how fast is the gas moving?

Q1

What is the area, in square meters, of 12 m telescope? ______ m^2

The answer is not 0.04. I need help!