In my recent
image of B22 I noticed that HH395 object near IC 2087 has a bit different coordinates than marked in Simbad database, so I suggested that it just moved away from the "parent" star over time. So I decided to check my suggestion using old observational data and here is what I found:
1. POSS I (1950) and POSS II (1991) red plates indeed show that position of HH395 is changing over time. Data is shown in gif in rev B.
2. HH395 travelled approximately 25" over a period of ~66 years (Dec 1950-Jan 2017). The distance to the star in the base of IC 2087 nebula (which most likely was the source) is 3.5' now, so this HH object is only about 550 years old! (Measurements were done in Aladin)
3. I was lucky to be able to estimate distance to B22 using Hipparcos data. One of the stars interacting with B22 happened to be in the HIP catalogue (relatively bright white star on the far left in my previous image, which clearly illuminates the dust, is a HIP 21759). According to Hipparcos, it's ~217 parsecs from us, so I assumed that the whole cloud together with IC 2087 and HH395 is approximately at the same distance. This means that HH395 travelled a distance of ~0.086 lyr in 66 years, which gives us tangential velocity of ~390 km/s. This is consistent with other available data.
Here is a cool presentation about HH objects.
PS. It is not a surprise that HH objects move, but it was interesting for me to conduct this small study.
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