| Emission nebula | |
|---|---|
| Planetary nebula | |
 NGC 6445 by PanSTARRS | |
| Observation data: J2000 epoch | |
| Right ascension | 17h 49m 15s[1] |
| Declination | −20° 00′ 35″ [1] |
| Distance | 4.5 Kly (1.38 Kpc)[2] ly |
| Apparent magnitude (V) | 11.2[3] |
| Apparent dimensions (V) | 0.53′ × 0.53′[1] |
| Constellation | Sagittarius |
| Designations | PK 008+03 1, Little Gem Nebula,[1] Box Nebula[4][5] |
NGC 6445, also known as the Little Gem Nebula or Box Nebula, is a planetary nebula in the constellation Sagittarius. It was discovered by William Herschel on May 28, 1786.[6] The distance of NGC 6445 is estimated to be slightly more than 1,000 parsecs based on the parallax measured by Gaia, which was measured at 0.9740±0.3151 mas.[7]
- ^ a b c d "NGC 6445". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 December 2018.
- ^ Stanghellini, Letizia; Shaw, Richard A.; Villaver, Eva (10 December 2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. Bibcode:2008ApJ...689..194S. doi:10.1086/592395. S2CID 119257242.
- ^ "Revised NGC Data for NGC 6445". spider.seds.org.
- ^ Michael E. Bakich (June 11, 2015). "Open cluster IC 4665, the Box Nebula (NGC 6445), and globular cluster". Astronomy.com. Retrieved 27 December 2018.
- ^ "Best of AOP: NGC 6445: The Box Nebula". www.noao.edu. National Optical Astronomy Observatory. Archived from the original on 28 December 2018. Retrieved 27 December 2018.
- ^ Seligman, Courtney. "NGC 6445 (= P-K 008+03.1 = "PGC 3517785"), the Little Gem Nebula". Celestial Atlas. Retrieved 19 November 2018.
- ^ Kimeswenger, S.; Barría, D. (14 August 2018). "Planetary nebula distances in Gaia DR2". Astronomy & Astrophysics. 616: L2. arXiv:1807.06368. Bibcode:2018A&A...616L...2K. doi:10.1051/0004-6361/201833647. S2CID 58893001.