Add the chicken, celery, 3 tablespoons tarragon, and wine to a greased slow cooker insert.

Cover and cook for seven hours on low.

Remove the chicken and set aside.

Add the yogurt and lemon juice to the sauce and turn the slow cooker temperature to high.

In a separate bowl, stir together the water and flour.

Add the mixture to the slow cooker, continuing to cook until sauce thickens.

Boil the angel hair pasta according to package directions, or until al dente.

Ladle the sauce over the chicken and pasta.