G79.29+0.46 Explained

G79.29+0.46 is a luminous blue variable star candidate located in the Cygnus X star formation region.[1] In the infrared and at radio wavelengths a prominent circular nebula can be seen. This nebula was formed by past mass-loss episodes of the LBV candidate.[2]

G79.29+0.46 was first reported as a suspected LBV by Higgs, Wendker & Landecker in 1993 with the DRAO Synthesis Telescope, which identified a nebula around a star that was a wind-blown shell.[3] As an LBV candidate, it has a spectrum with many emission lines, H-alpha being the strongest. The spectrum is similar to other LBVs and Be supergiants. The strength of the H-alpha line suggest very dense winds around this star.[4] The star is currently losing mass at a rate of /year and it is surrounded by a dusty envelope with a temperature of 40 to . The star is considered only a candidate LBV because it has not shown variability in the optical or near-infrared over 20 years. It has been suggested that it is a LBV in the quiescent stage.

From radio and infrared images a detached shell can be seen that shows evidence of two mass-loss episodes. This shell has a mass of and a radius of 0.66 parsecs,[5] and it contains carbon monoxide[6] and ammonia.

Notes and References

  1. Gaia Collaboration . 2022-05-01 . VizieR Online Data Catalog: Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022) . VizieR Online Data Catalog . I/355. 10.26093/cds/vizier.1355 . 2022yCat.1355....0G .
  2. Rizzo . J. R. . Palau . Aina . Jiménez-Esteban . F. . Henkel . C. . 2014-04-01 . Ammonia observations in the LBV nebula G79.29+0.46. Discovery of a cold ring and some warm spots . Astronomy and Astrophysics . 564 . A21 . 10.1051/0004-6361/201323170 . 1401.6186 . 2014A&A...564A..21R . 119246133 . 0004-6361.
  3. 1993AAS...183.5801H . Discovery of a Young Stellar-Wind Shell in Cygnus X . Higgs . L. A. . Wendker . H. J. . Landecker . T. L. . American Astronomical Society Meeting Abstracts . 1993 . 183 .
  4. Voors . R. H. M. . Geballe . T. R. . Waters . L. B. F. M. . Najarro . F. . Lamers . H. J. G. L. M. . 2000-10-01 . Spectroscopy of the candidate luminous blue variable at the center of the ring nebula G79.29+0.46 . Astronomy and Astrophysics . 362 . 236–244 . astro-ph/0008293 . 2000A&A...362..236V . 0004-6361.
  5. Agliozzo . C. . Noriega-Crespo . A. . Umana . G. . Flagey . N. . Buemi . C. . Ingallinera . A. . Trigilio . C. . Leto . P. . 2014-05-01 . The candidate luminous blue variable G79.29+0.46: a comprehensive study of its ejecta through a multiwavelength analysis. Monthly Notices of the Royal Astronomical Society . 440 . 2 . 1391–1409 . 10.1093/mnras/stu296 . 1402.2983 . 2014MNRAS.440.1391A . 0035-8711.
  6. Rizzo . J. R. . Jiménez-Esteban . F. M. . Ortiz . E. . 2008-07-01 . Discovery of Warm and Dense Molecular Gas Surrounding the Ring Nebula G79.29+0.46 . The Astrophysical Journal . 681 . 1 . 355–364 . 10.1086/588455 . 0804.0266 . 2008ApJ...681..355R . 17847585 . 0004-637X.

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