Does “a period of 40 days” mean that it orbits the star in only 40 days?
And wouldn’t that make it very close to the star?
And by “warm” Neptune, they mean boiling?
All true. But the signal only comes from the general direction of the warm Neptune planet, the only planet they know about in that system. The signal might actually be coming from another planet that’s in orbit around the star.
To get a notion of ‘warm neptune,’ google ‘hot jupiter.’