Current Dwarf Planet Count

[Christopher K.]

Well, at this time the term dwarf planet seems to be defined slightly differently by different groups. Mike Brown's dwarf planet page lists dozens while NASA's Solar System Exploration section lists five--Ceres, Pluto, Makemake, Haumea and Eris.

Here are the diameters of each...
Ceres, 930 km
Pluto, 2302 km
Makemake, ??? (believed to be slightly smaller than Pluto)
Haumea, ??? (possibly egg-shaped)
Eris, 2924? km (27% bigger than Pluto)

In 2008 a subdivision of dwarf planet called plutoid was created. "Plutoid" refers to all transneptunian dwarf planets. Pluto and Eris are on that list.

Of course, I think we should stick to the International Astronomical Union's definition of "dwarf planets". I wonder, however, as the detection equipment becomes stronger and stronger (just think of Kepler and the James Webb) whether the argument about planet versus dwarf planet will move to other star systems, or if we'll have settled it by then.

More information at:
http://solarsystem.nasa.gov/planets/pro ... play=Moons
http://web.gps.caltech.edu/~mbrown/dwarfplanets/
http://www.iau.org/public/pluto/

[Christopher K.]

Now, the entire elementary school set is a dwarf planet generation! If we're sending out TESS to search for exoplanets, will we aim soon another machine at the Kuiper Belt?

More information:
https://starchild.gsfc.nasa.gov/docs/St ... anets.html

[Christopher K.]

The "planet"/"dwarf planet" conundrum is not helped by the fact that different segments of professional STEM studies use different definitions of the word. This issue was brought to the forefront of public thought in 2006 when the category "dwarf planet" was created by the International Astronomical Union.

On Friday 9 October at 6:30pm, personnel at the Highland Road Park Observatory will have a remote discussion with patrons regarding the idea of "planet". Interested parties will be able to sign in at 6pm. The discussion is for ages fourteen and older.

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Join from PC, Mac, Linux, iOS or Android: https://brec-tech.zoom.us/j/94648307769 ... ZtbTgzQT09
Password: 393421

Or Telephone:
Dial:
USA 404 443 2170
USA 8778487030 (US Toll Free)
Conference code: 291855

Find local AT&T Numbers: https://www.teleconference.att.com/serv ... ode=291855

Please do not cut and paste; just click the hyperlinks.
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More information:
https://solarsystem.nasa.gov/planets/in-depth/
https://ssd.jpl.nasa.gov/?planet_iau_note