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axialintellectual t1_jcszb2m wrote

Reply to comment by arealuser100notfake in Containing an incredible half-million stars, this 8-billion-year-old cosmic bauble is one of the largest and brightest globular clusters ever discovered. Credits: ESA/Hubble by Davicho77

Significantly closer! The stellar density in the Solar neighborhood is around 0.14 pc^(-3), in globular cluster cores that goes up to ~ 1000 pc^(-3). That may also mean that the formation (and survival) of any planets is significantly suppressed around the stars in a globular cluster.

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beef-o-lipso t1_jctc6ok wrote

Why would an increase in stellar density suppress planet formation? Curious.

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axialintellectual t1_jctcpbv wrote

Good question! On the planet formation side: protoplanetary disks would be heavily irradiated by the other nearby stars, which tends to shorten the lifetime available to planet formation; they can also get disrupted by flyby-events. If a planetary system does form, those same flybys continue and can disrupt it over longer timescales. On the other hand, we don't - to the best of my knowledge - have very good constraints on planet occurrence rates in globular clusters, because they're far away and hard to observe, but I would say from a theoretical point of view these are quite well-understood mechanisms.

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beef-o-lipso t1_jctdq0p wrote

Thanks! I guess I wouldn't have expected much interaction between the systems.

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axialintellectual t1_jcth8h9 wrote

It's still rare, but the orders of magnitude higher density, and the fact that globular clusters get quite old, means that there's a lot of opportunities. Here's a recent paper about the topic, if you want to read more.

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