https://www.techspot.com/news/70340-bungie-destiny-2-pc-beta-arrive-august-28.html
Summary:
-- CPU: minimum is a 2C/4T Core i3, recommended is a 4C/4T i5-2400 (3.1GHz base/3.2-3.4GHz Turbo). You have a 4C/4T i5-3470 (3.2GHz base/3.4-3.6GHz Turbo), so you're more than fine.
-- RAM: minimum is 6GB, recommended is 8GB (so assuming it needs 64-bit Windows). You only have 4GB, so you'll want to upgrade to 8GB of RAM pronto.
-- GPU: minimum is a 2GB GTX 660 or Radeon HD 7850, recommended is a GTX 970 or R9 390, or a more modern equivalent. Your GTX 650 definitely won't cut it. At a minimum, I'd consider getting a GTX 1050 (1 step up from the 660) or 1050Ti (2 steps up); for a more long-term upgrade, consider getting a GTX 1060...