How do i calculate how long ago light seen from earth today was emitted from a star

how do i calculate how long ago light seen from earth today was emitted from a star if all i know is the distance of that star from earth?

for example 4.4pc?

>>I'm pretty sure it involves the hubble constant and redshift somehow, I just cant seem to wrap my head around altering the equation to use it for distance in parsec from earth..<<

You are incorrect.

Number of light years = number of parsecs / 3.26

Number of light years = number of years ago light was emitted by the star

Edit: I can manage without the condescending tone, thanks. If a star is only 4.4pc away then it is within our own Galaxy and you DO NOT consider the expansion of the Universe in such cases because local gravitational effects swamp it.

So you tell me that the star is 4.4 parsecs away, and that the Hubble constant is 71km/sec/Mpc. The means the expantion of spaace between me and that star expands by 31 centimeters per second. Now, ignoring the fact that I'm not in static space, what with the Earth spinning and gyrating, and me walking and stuff, the speed of light is a billion times faster. Unless you meant the star was 4.40000000000 parsecs away the error in my time calculation due to expantion will be lost in the rounding.

You are over thinking this.
Just convert parsecs to light years, and the time in years is the same as the distance in light years.
1 Parsec = 3.26163626 light year so 4.4 parsecs = 4.4 * 3.26163626 = about 14.35 light years.
So 14.35 years.

You know the speed of light.
If you have the distance to the star, you know the time lag involved.
(IIRC 1 pc = 3.8 Lt yr.s. - Check that number though..)

You need some practice. I love you.