Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 16010 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that PGC 29031 is about 745 million light-years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the pair was about 700 million light-years away at the time the light by which we see it was emitted, about 720 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of about 0.35 by 0.15 arcmin for the western component, about 0.4 by 0.2 arcmin for the eastern component, and about 0.4 by 0.4 arcmin for the overall structure (from the images below), the western component spans about 70 thousand light-years (primarily north-to-south), the eastern about 80 thousand light-years (primarily north-to-south), and the overall structure spans about 80 thousand light-years (in all directions).

Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 1015 km/sec (and H₀ = 70 km/sec/Mpc), PGC 29086 is about 45 to 50 million light years away, in good agreement with redshift-independent distance estimates of about 20 to 50 million light years. Given that and its apparent size of about 4.05 by 0.3 arcmin (from the images below), the galaxy is about 55 thousand light years across.

Note About the NED/LEDA Designation(s): NED lists this galaxy as UGC 05442, and among other designations, as PGC 29388 (which is correct) and LEDA 5056954, which is actually the designation of the much more distant background galaxy that is visible right through the foreground galaxy, and happens to be in almost the same place as the apparent center of the foreground galaxy. (LEDA lists the background galaxy as PGC 5056954, and although such a "high-number" designation usually does not show up in a search of the database, PGC 5056954 does return a brief entry about the background galaxy.)
Physical Information: The nature of PGC 29388 is unclear in the low-resolution SDSS/DSS images shown below, and until early 2020 those were the best images available, so NED and LEDA both listed the galaxy as an irregular galaxy of type I or Im (and may continue to do so for some time to come). However, the HST image shows that it is a dwarf elliptical with such a small mass (probably no more than a billion or so stars lie within it, compared to the three or four hundred billion stars in our own galaxy) that it is possible to see numerous background galaxies right through it, most noticeably PGC 5056954, which is so close to the apparent location of the center of PGC 29388 (only about 0.2 arcmin to the west of the relatively uncertain position of that center) that it looks almost like a peculiar structure inside the foreground galaxy. The poorly defined structure of the galaxy in the low-resolution images is undoubtedly the reason that it was incorrectly listed as an irregular galaxy, but the more obvious presence of PGC 5056954 may have contributed to that error.
 Based on a recessional velocity relative to the Cosmic Microwave Background of only about 75 km/sec (and H₀ = 70 km/sec/Mpc), PGC 29388 is about 3 or 4 million light years away, but redshift-independent distance estimates of about 10 to 15 million light years are probably more accurate, because the random motions of galaxies in a given region relative to each other (known as "peculiar velocities") are typically considerably larger than the recessional velocity of this galaxy (in other words, its recessional velocity is too small to be a reliable measure of its distance). As a result, for the rest of this discussion I have chosen to use 12.5 million light years as its most likely distance. Given that and its apparent size of about 2.5 by 1.4 arcmin (from the images below), PGC 29388 is probably about 8 to 10 thousand light years across.

Physical Information: PGC 29488's recessional velocity of 285 km/sec is too small in comparison to peculiar (non-Hubble-expansion) velocities to be of any use for determining its distance, but redshift-independent distance estimates range from 650 thousand to 880 thousand light years, with the most generally accepted value being just over 800 thousand light yeas away. This makes it one of the more distant satellites of our own galaxy (for that reason it is briefly discussed on the page about Our Galaxy and its Satellites), and definitely a member of our Local Group. It is a dwarf spheroidal (elliptical galaxy), and between its small size and distance, appears almost more like a loose collection of stars than a galaxy (it is also difficult to see because it is close to the first-magnitude star Regulus). Its position in Leo has led to its designation as Leo I (another similar galaxy in the same general area being called Leo II). Given its presumed distance and apparent size by 9.8 by 7.4 arcmin, Leo I is almost certainly less than 2500 light years across. Used by the de Vaucouleurs Atlas of Galaxy Types as an example of galaxy type dSph.