AFGL 2298

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AFGL 2298
AFGL2298LightCurve.png
A near-infrared (J band) light curve for AFGL 2298, adapted from Clark et al. (2009) [1]
Observation data
Epoch J2000        Equinox J2000
Constellation Aquila
Right ascension 19h 00m 10.89s [2]
Declination +03° 45′ 47.1″ [2]
Characteristics
Spectral type B8I, [3] B:I:[e], [4] B0-0.5I [5]
Apparent magnitude  (J)12.164 [2]
Apparent magnitude  (H)8.918 [2]
Apparent magnitude  (K)6.91 [6]
Variable type LBV [4]
Astrometry
Distance 30,000±10,000  ly
(10,000±3,000 [4]   pc)
Absolute bolometric
magnitude  (Mbol)		−11.25 [1]
Details
Radius 158 - 385 [1]   R☉
Luminosity 1,300,000 - 2,000,000 [1]   L☉
Temperature 11,000 - 15,500 [1] or 26,000 [5]   K
Other designations
V1672 Aql, RAFGL 2298, IRAS 18576+0341, 2MASS J19001089+0345471 [7]
Database references
SIMBAD data

AFGL 2298, also known as IRAS 18576+0341, is a luminous blue variable star (LBV) located in the constellation Aquila, very close to the galactic plane. Its distance is not well known; it may be anywhere between 23,000 and 42,000 light years (7,000 to 13,000 parsecs) away from the Earth. [4] Despite being extremely luminous, it is extremely reddened by interstellar extinction, so its apparent magnitude is brighter for longer-wavelength passbands; in fact, in visual wavelengths it is completely undetectable. [7]

AFGL 2298 has an absolute bolometric magnitude of −11.25, [1] making it one of the most luminous stars known. Indeed, many of the hottest and most luminous stars known are luminous blue variables and other early-type stars. However, like all LBVs, AFGL 2298 is highly variable and the bolometric magnitude refers to its peak luminosity. [1] Its status as an LBV was confirmed in 2003. [4]

Like most extremely massive stars, AFGL 2298 is undergoing mass loss. [5] For example, in 2005 it was estimated to be losing 3.7×10−5 solar masses each year, [5] although the rate of mass loss itself varies frequently and dramatically. [1] The stellar mass is currently being ejected as a nebula around the star (similar to AG Carinae), which was imaged by the Very Large Telescope in 2010. [8] The nebula was found to be fairly circular, and the properties of the dust appeared to be constant throughout the entire nebula. [8]

Properties of AFGL 2298 over time [1]
Effective temperature  (K)Mass loss rate (M☉/yr) Bolometric luminosity  (L☉)
June 200111,7004.5×10−51.5×106
August 200210,9001.2×10−41.3×106
June 200610,3005.2×10−52.0×106
May 200710,9004×10−51.5×106

See also

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References

  1. 1 2 3 4 5 6 7 8 9 Clark, J. S.; et al. (2009). "Bolometric luminosity variations in the luminous blue variable AFGL2298". Astronomy and Astrophysics. 507 (3): 1555–1565. arXiv: 0909.4160 . Bibcode:2009A&A...507.1555C. doi:10.1051/0004-6361/200912358. S2CID   119187994.
  2. 1 2 3 4 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.
  3. ↑ Ramírez Alegría, S.; Herrero, A.; Rübke, K.; Marín-Franch, A.; García, M.; Borissova, J. (2018). "Identifying two groups of massive stars aligned in the l 38° Galactic direction". Astronomy and Astrophysics. 614: A116. arXiv: 1801.08683 . Bibcode:2018A&A...614A.116R. doi:10.1051/0004-6361/201731720. S2CID   119427413.
  4. 1 2 3 4 5 Clark, J. S.; et al. (2003). "Confirmation of the Luminous Blue Variable nature of AFGL 2298". Astronomy and Astrophysics. 403 (2): 653–658. Bibcode:2003A&A...403..653C. doi: 10.1051/0004-6361:20030389 .
  5. 1 2 3 4 Umana, G.; Buemi, C. S.; Trigilio, C.; Leto, P. (2005). "Current day mass loss rate for Luminous Blue Variable IRAS 18576+0341". Astronomy and Astrophysics. 437 (1): L1–L5. Bibcode:2005A&A...437L...1U. doi: 10.1051/0004-6361:200500126 .
  6. ↑ Kazarovets, E. V. (2006). "The 78th Name-List of Variable Stars". Information Bulletin on Variable Stars. 5721: 1. Bibcode:2006IBVS.5721....1K.
  7. 1 2 "AFGL 2298". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 26 January 2017.
  8. 1 2 Buemi, C. S.; et al. (2010). "VISIR/VLT and VLA Joint Imaging Analysis of the Circumstellar Nebula Around IRAS 18576+0341". The Astrophysical Journal. 721 (2): 1404–1411. arXiv: 1008.0997 . Bibcode:2010ApJ...721.1404B. doi:10.1088/0004-637X/721/2/1404. S2CID   119281049.
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