Parsecs

2M1207b - Discovery, Identification and Properties
... for the distance to 2M1207b was 70 parsecs ... American astronomer Eric Mamajek reported a more accurate distance (53 ± 6 parsecs) to 2M1207b using the moving cluster method ... moving cluster distance, leading to a distance estimate of 52.75+1.04 −1.00 parsecs or 172 ± 3 light years ...

U Geminorum
... for U Geminorum have varied from 52 parsecs (170 light-years) to 112 parsecs (370 light-years), with a best estimate of 82 parsecs (270 light-years) ...

Gliese Catalogue Of Nearby Stars - First Edition and Supplements
... of nearly one thousand stars located within 20 parsecs (65 ly) of Earth, listing their known properties and ordered by right ascension ... as the Catalogue of Nearby Stars in 1969, extending the range out to 22 parsecs (72 ly) ... and associates, extended the range out to 25 parsecs (82 ly) ...

Cygnus X-1 - Star System
... distance to this system is about 1,860 ± 120 parsecs (6,100 ± 390 light-years) ... named Cygnus OB3, which is located at roughly 2,000 parsecs from the Sun ... HDE 226868 is about 60 parsecs from the center of the association, and could have reached that separation in about 7±2 Ma—which roughly agrees with estimated age of the association ...

Distance Modulus - Definition
... It is related to the distance in parsecs by This definition is convenient because the observed brightness of a light source is related to its distance by the inverse square law (a source twice as ... Suppose a light source has luminosity L(d) when observed from a distance of parsecs, and luminosity L(10) when observed from a distance of 10 parsecs ... Isolating from the equation, we find that the distance in parsecs is given by The uncertainty in the distance in parsecs (δd) can be computed from the uncertainty in the distance modulus (δμ) using which is ...