4 ms·
It's odd that the article doesn't mention the phrase "brown dwarf", which is what 2MASS J23062928-0502285 is. (See http://simbad.u-strasbg.fr/simbad/sim-id?Iden
by _kst_ 10y ago
It's odd that the article doesn't mention the phrase "brown dwarf", which is what 2MASS J23062928-0502285 is. (See http://simbad.u-strasbg.fr/simbad/sim-id?Ident=2MASS+J23062928-0502285 http://simbad.u-strasbg.fr/simbad/sim-id?Ident=2MASS+J230629..., linked from the article.)
The phrase "ultracool dwarf star" is descriptive, but both less familiar and less precise than "brown dwarf". Perhaps the author assumed the audience wouldn't know what a brown dwarf is, but a lot of us do (and the rest could have it explained easily enough).
- ak4g 10y ago"Brown dwarf" also doesn't command the same je ne sais quoi of "ultracool".
- _kst_ 10y agoPerhaps it isn't really a brown dwarf. According to http://www.slate.com/blogs/bad_astronomy/2016/05/03/three_earth_sized_exoplanets_found_around_nearby_red_dwarf_star.html http://www.slate.com/blogs/bad_astronomy/2016/05/03/three_ea... : > TRAPPIST-1 is an M8 dwarf, only 0.08 times the mass of the Sun; just barely massive enough to fuse hydrogen into helium in its core. If it were much lower mass we wouldn’t call it a star at all (we’d say it’s a brown dwarf). And the Wikipedia article on brown dwarfs: https://en.wikipedia.org/wiki/Brown_dwarf https://en.wikipedia.org/wiki/Brown_dwarf > Brown dwarfs are substellar objects not massive enough to sustain hydrogen-1 fusion reactions in their cores, unlike main-sequence stars. Apparently TRAPPIST-1 is an actual star, which makes it a (small, cool) red dwarf, not a brown dwarf. But it is near the dividing line. (A brown dwarf with planets would be interesting, but they probably wouldn't be potentially habitable.)