IRAS 19475+3119

IRAS 19475+3119 is a protoplanetary nebula in the constellation of Cygnus, 15,000 light-years away. The central star, V2513 Cygni, is an F-type post-AGB star.

IRAS 19475+3119

IRAS 19474+3119
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension  19h 49m 29.5627s[1]
Declination +31° 27′ 16.221″[1]
Apparent magnitude (V) 9.52[2] (9.33 - 9.50[3])
Characteristics
Evolutionary stage Protoplanetary nebula
Spectral type F3 Ibe[4]
Variable type SRd[3]
Astrometry
Proper motion (μ) RA: -0.6[2] mas/yr
Dec.: -2.8[2] mas/yr
Distance4,900[5] pc
Details
Mass0.63[5] M☉
Radius58[5] R☉
Luminosity8,300[5] L☉
Surface gravity (log g)0.5[5] cgs
Temperature7,200[4] K
Metallicity [Fe/H]−0.25[4] dex
Other designations
V2513 Cyg, BD+31° 3797, HD 331319
Database references
SIMBADdata

The brightest portion of the nebula shows a quadrupolar structure, with elongated bipolar lobes, all surrounded by a faint halo.[6]

The distance is essentially unknown. Assumptions about the luminosity have been used to estimate the distance and other stellar parameters. At an assumed kinematical distance of 4.9 kpc, the luminosity is 8,300 L☉ and the radius 58 R☉.[5] The star was originally at least 2.5 M☉ and is now 0.63 M☉.[6] Assuming a luminosity of 3,500 L☉, the distance becomes 1.5 kpc.[7] Estimates based on the oxygen spectral line strengths give much higher values luminosities with an absolute magnitude of at least −8.[4]

The central star is variable, from about magnitude 9.33 to 9.50. A primary period of 41 days has been determined, but a slightly shorter secondary period leads to long beats causing variations in the amplitude and apparent period from year to year. The variations are caused by stellar pulsations, with the star being brightest when it is hottest. The temperature varies by up to 400 K.[8]

References
  1. Hog, E.; Kuzmin, A.; Bastian, U.; Fabricius, C.; Kuimov, K.; Lindegren, L.; Makarov, V. V.; Roeser, S. (1998). "The TYCHO Reference Catalogue". Astronomy and Astrophysics. 335: L65. Bibcode:1998A&A...335L..65H.
  2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862.
  3. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  4. Klochkova, V. G.; Panchuk, V. E.; Tavolzhanskaya, N. S. (2002). "HD 331319: A Post-AGB F Supergiant with He I Lines". Astronomy Letters. 28: 49. Bibcode:2002AstL...28...49K. doi:10.1134/1.1434453.
  5. Hsu, Ming-Chien; Lee, Chin-Fei (2011). "An Envelope Disrupted by a Quadrupolar Outflow in the Pre-planetary Nebula IRAS 19475+3119". The Astrophysical Journal. 736: 30. arXiv:1105.2410. Bibcode:2011ApJ...736...30H. doi:10.1088/0004-637X/736/1/30.
  6. Sahai, Raghvendra; Sánchez Contreras, Carmen; Morris, Mark; Claussen, Mark (2007). "A Quadrupolar Preplanetary Nebula: IRAS 19475+3119". The Astrophysical Journal. 658: 410. Bibcode:2007ApJ...658..410S. doi:10.1086/511294.
  7. Vickers, Shane B.; Frew, David J.; Parker, Quentin A.; Bojičić, Ivan S. (2015). "New light on Galactic post-asymptotic giant branch stars - I. First distance catalogue". Monthly Notices of the Royal Astronomical Society. 447 (2): 1673. arXiv:1403.7230. Bibcode:2015MNRAS.447.1673V. doi:10.1093/mnras/stu2383.
  8. Hrivnak, Bruce J.; Lu, Wenxian; Nault, Kristie A. (2015). "Variability in Proto-planetary Nebulae. IV. Light Curve Analysis of Four Oxygen-rich, F Spectral Type Objects". The Astronomical Journal. 149 (6): 184. arXiv:1503.09120. Bibcode:2015AJ....149..184H. doi:10.1088/0004-6256/149/6/184.
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