# What's the number density of Oumuamua like objects?

Recently, the fly-through the Solar system of the inter-stellar object (ISO) Oumuamua caused quite a stir in the astronomy community. I wonder whether there are reliable estimates for the (local) number density of such objects. Such estimates could be based on the `Oumuamua event (when they are necessarily rather crude owing to very low-number statistics) or on any other constraints. A related question is: how close to Earth must an ISO pass to be detected with today's instruments, or 10, 25, 50 years ago?

• Estimates for LSST (8.4m survey telescope, 6.5m effective area) are ~1 interstellar object detected per year with considerable uncertainty – astrosnapper Jun 21 '19 at 16:30
• @astrosnapper That's not at all what I asked, though somewhat related. – Walter Jun 21 '19 at 19:08
• @astrosnapper do you have a reference for that? – Walter Jun 21 '19 at 19:28
• What research did you do? For me, this paper by Do, Tucker and Tonry comes up on the first page of Google search results for "number density of oumuamua" - does it answer your question? – user24157 Jun 22 '19 at 18:02
• @mistertribs Though you may also see this ui.adsabs.harvard.edu/abs/2017AJ....153..133E/abstract (quoted from the paper you dug up), which prior to the detection of 'Oumuamua estimated the density 1000 times smaller. – Walter Jun 22 '19 at 21:13