KIC 9832227

KIC 9832227 (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 29m 15.948s[1]
Declination +46° 37′ 19.89″[1]
Apparent magnitude (V) 12.27 – 12.46[2]
Distance1843 ly
(565[3] pc)
Period (P)0.4282579 days
Semi-major axis (a)2.992 R
Inclination (i)53.2°
Periastron epoch (T)2455688.49913
Mass1.395 M
Radius1.581 R
Luminosity2.609 L
Surface gravity (log g)4.19 cgs
Temperature5800 K
Rotational velocity (v sin i)149.7 km/s
Mass0.318 M
Radius0.830 R
Luminosity0.789 L
Surface gravity (log g)4.10 cgs
Temperature5920 K
Rotational velocity (v sin i)84.7 km/s
Other designations
2MASS J19291594+4637198, KIC 9832227, ASAS J192916+4637.3, GSC 03543-01211
Database references
A light curve for KIC 9832227, plotted from TESS data[4]

KIC 9832227 is a contact binary star system[5] in the constellation Cygnus, located about 1,843 light-years away.[6] It is also identified as an eclipsing binary with an orbital period of almost 11 hours.[5] In 2017, the system was predicted to result in a merger in 2022.2 (± 0.6 years), producing a luminous red nova (LRN) reaching an apparent magnitude of 2,[6] or about the brightness of Polaris, the North Star. The LRN would remain visible to the naked eye for roughly a month. The merger of the two stellar cores was predicted to give birth to a new, hotter, more massive main-sequence star. However, a reanalysis of the data in September 2018 revealed that the prediction had been based on a wrongly timed observation, negating the predicted merger.[7][8][9]

The period of the variations in KIC 9832227 has been observed to be growing shorter since 2013, leading to the prediction of the merger in or around 2022.[10] In September 2018, it was announced that the original prediction was based on a timing offset of 12 hours in one of the datasets. This shows that the period had actually been increasing up to about 2008. The cause for the period variation is still unknown, but it is unlikely that the system will end in a merger at the predicted time.[7][8][11]

See also


  1. ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  2. ^ "ASAS J192916+4637.3". AAVSO. Retrieved 7 January 2017.
  3. ^ a b c Molnar, Lawrence A.; Van Noord, Daniel M.; Steenwyk, Steven D.; Spedden, Chris J.; Kinemuchi, Karen (2015). "A prediction of a luminous red nova eruption" (PDF). American Astronomical Society. 225 (225): 415.05. Bibcode:2015AAS...22541505M. Archived from the original (PDF) on 7 January 2017.
  4. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  5. ^ a b Kinemuchi, Karen (2013-10-01). "To Pulsate or to Eclipse? Status of KIC 9832227 Variable Star". arXiv:1310.0544 [astro-ph.SR].
  6. ^ a b Molnar, Lawrence A.; Van Noord, Daniel; Kinemuchi, Karen; Smolinski, Jason P.; Alexander, Cara E.; Kobulnicky, Henry A.; Cook, Evan M.; Jang, Byoungchan; Steenwyk, Steven D. (2017). "KIC 9832227: A red nova precursor". American Astronomical Society. 229: 417.04. Bibcode:2017AAS...22941704M.
  7. ^ a b Molnar, Lawrence A. (7 September 2018). "Supplementary material to Calvin College press release "Team of researchers challenge bold astronomical prediction", September 7, 2018". Retrieved 8 September 2018.
  8. ^ a b Kucinski, Matt (7 September 2018). "Team of researchers challenge bold astronomical prediction". Retrieved 8 September 2018.
  9. ^ Parks, Jake (7 September 2018). "Two stars will NOT merge and explode into red fury in 2022".
  10. ^ Carlisle, Camille (6 January 2017). "Paired Stars in Cygnus En Route to Merger". Sky and Telescope. Retrieved 12 January 2017.
  11. ^ Socia, Quentin J.; Welsh, William F.; Short, Donald R.; Orosz, Jerome A.; Angione, Ronald J.; Windmiller, Gur; Caldwell, Douglas A.; Batalha, Natalie M. (11 September 2018). "KIC 9832227: Using Vulcan Data to Negate the 2022 Red Nova Merger Prediction". Astrophysical Journal Letters. 864 (2): L32. arXiv:1809.02771. Bibcode:2018ApJ...864L..32S. doi:10.3847/2041-8213/aadc0d. S2CID 56134618.