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Across 3. a white dwarf star that has cooled, no visible heat or light emitted 5. a spiral galaxy that contains our solar system 6. huge, diffuse cloud of H gas & dust form stars in intergalatic space 9. ionized gas ejected from star surface 12. causes astronomical scintillation, bent or refracted light from the density changes 15. without rotational symmetry or organized structure 16. closest to Earth, 4.3 light yrs from Sun, Proxima Centauri 17. converting H into He atoms releasing enormous energy 20. composed of a flattened disk of stars with arms & a large bulge 21. stars apparent magnitude when placed at a distance of 10 pc from observer 22. nothing can escapeits gravity, not even light, from a red supergiant then supernova 23. human grouping of stars in the night sky into a recognizable pattern 24. no arms, stars are distributed in a circular pattern or elongated

Down 1. uses luminosity and surface temperature to classify stars, spectral classification 2. Sun passes through the course of a year, 12 or now 13 star patterns 4. unorganized collection of stars, ex are Pleiades & Hyades 7. 2 stars locked in elliptical orbit around their center of mass or barycenter 8. any star comparable or smaller than our Sun, including the Sun 10. dispersion of an objects light into its component colors 11. a red supergiant, 2nd brightest star in Orion, "beetle juice" 13. modern astronomical scale of stellar objects brightness 14. part of local group, farthest object seen with naked eye, closest galaxy to ours 18. spectral type O or B, very rare & bright, blue giant star 19. organized collections of stars, dust, gas & celestial bodies, bound by gravity 20. a star with radius 100 - 1000 X that of Sun, like Betelgeuse