Epoch 2000 Equinox
|Right ascension||19 26 48.095|
|Declination||+11 21 16.74|
|Apparent magnitude (V)||11.66|
|B−V color index||2.32|
IRC+10420, V1302 Aql, IRAS 19244+1115
IRC+10420's spectrum has changed from late F to A during last decades without experiencing changes in its luminosity. This suggests IRC+10420 is a former red supergiant that is evolving blueward on the Hertzsprung-Russell diagram to become a Luminous Blue Variable, a Wolf-Rayet star, or even a pre-supernova. Models suggest it started its life as a 40-50 solar masses star that lost most of its mass due to strong stellar winds leaving it with just 10 solar masses and that the star - which actually has a high surface temperature - is totally enshrouded in the matter it has expelled appearing as a fake photosphere, so IRC+10420 appears with a later spectral type as we see just the expelled dust and gas it has blown out during its life and not the star itself.
IRC+10420 is surrounded by a reflection nebula with a mass of 30-40 solar masses that has been made by the material expelled by the strong stellar winds of its central star. This nebula has been studied with the help of the Hubble Space Telescope, showing a complex structure that includes arcs, rays, and condensations and that has been compared by the one surrounding the red hypergiant VY Canis Majoris.
- Volk, Bruce J.; Kwok, Sun; Volk, Kevin M. (1989). "A study of several F and G supergiant-like stars with infrared excesses as candidates for proto-planetary nebulae". Astrophysical Journal 346: 265. Bibcode:1989ApJ...346..265H. doi:10.1086/168007.
- Nieuwenhuijzen, H.; De Jager, H. (2000). "Checking the yellow evolutionary void. Three evolutionary critical Hypergiants: HD 33579, HR 8752 & IRC +10420". Astronomy and Astrophysics 353: 163. Bibcode:2000A&A...353..163N.
- Oudmaijer, René D.; Groenewegen, M. A. T.; Matthews, H. E.; Blommaert, J. A. D. L.; Sahu, K. C. (1996). "The spectral energy distribution and mass-loss history of IRC+10420". Monthly Notices of the Royal Astronomical Society 280 (4): 1062. Bibcode:1996MNRAS.280.1062O. doi:10.1093/mnras/280.4.1062.
- Humphreys, Roberta M. (2007). "The Circumstellar Environments of the Cool Hypergiants: Implications for the Mass Loss Mechanism". Revista Mexicana de Astronomía y Astrofísica 30: 6–11. ISSN 0185-1101.
- Humphreys, Roberta M.; Davidson, Kris; Smith, Nathan (2002). "Crossing the Yellow Void: Spatially Resolved Spectroscopy of the Post–Red Supergiant IRC +10420 and Its Circumstellar Ejecta". The Astronomical Journal 124 (2): 1026. arXiv:astro-ph/0205247. Bibcode:2002AJ....124.1026H. doi:10.1086/341380.
- Humphreys, Roberta M.; Smith, Nathan; Davidson, Kris; Jones, Terry Jay; Gehrz, Robert T.; Mason, Christopher G.; Hayward, Thomas L.; Houck, James R.; Krautter, Joachim (1997). "HST and Infrared Images of the Circumstellar Environment of the Cool Hypergiant IRC + 10420". Astronomical Journal 114: 2778. Bibcode:1997AJ....114.2778H. doi:10.1086/118686.