W Hydrae

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W Hydrae
WHyaLightCurve.png
The visual band light curve of W Hydrae, from AAVSO data [1]
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Hydra
Right ascension 13h 49m 01.998s
Declination −28° 22 03.49
Apparent magnitude  (V)7.7 - 11.6 [2]
Characteristics
Spectral type M7.5e-M9ep [3]
Apparent magnitude  (J)-1.7 [4]
Variable type Mira
Astrometry
Parallax (π)10.18 ± 2.36  mas [5]
Distance 320+98
−59
  ly
(98+30
−18
  pc) [5]
Details
Mass 2.14+1.07
−0.71
[6]   M
Radius 436+134
80
[7] [a]   R
Luminosity 9,290+2,460
−1,940
[6]   L
Temperature 3,000 [6]   K
Other designations
W Hya, CCDM J13491-2822A, HD 120285, RAFGL 1650, CPD-27° 4792, HIP 67419, SAO 181981, AAVSO 1343-27, IRAS 13462-2807, GC 18659, TYC 6728-19-1.
Database references
SIMBAD data

W Hydrae is a Mira-type variable star in the constellation Hydra. The star is nearly located within the Solar neighborhood, at 320 light years from the Solar System. It has a visual apparent magnitude range of 5.6 to 10. In the near-infrared J band it has a magnitude of -1.7, [4] is the 7th brightest star in the night sky, and is even brighter than Sirius.

Contents

Water and dust masers

The star also shows signs of intense water emissions, indicative of the presence of a wide disk of dust and water vapour. [8] Such emissions cover a zone spanning between 10.7 Astronomical Units (within Saturn's orbital zone) and 1.2 parsecs (or nearly 247,500 Astronomical Units, as far away as the Oort Cloud in Solar System).

Notes

  1. Radius calculated using a distance of 98+30
    −18
      parsecs
    and an angular diameter of 41.4  milliarcseconds (0.041 arcsec). 98 0.041 = diameter of 4.06  AU , which is multiplied by 107.5 to convert from AU to R.

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<span class="mw-page-title-main">W Cygni</span> Semi-regular variable star in the constellation Cygnus

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<span class="mw-page-title-main">R Leonis Minoris</span> Variable star in the constellation Leo Minor

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<span class="mw-page-title-main">W Coronae Borealis</span> Star in the constellation Corona Borealis

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<span class="mw-page-title-main">U Microscopii</span> Star in the constellation Microscopium

U Microscopii is a Mira variable star in the constellation Microscopium. It ranges from magnitude 7 to 14.4 over a period of 334 days. The Astronomical Society of Southern Africa in 2003 reported that observations of U Microscopii were very urgently needed as data on its light curve was incomplete.

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<span class="mw-page-title-main">W Aquilae</span> Variable star in the constellation Aquila

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<span class="mw-page-title-main">S Cassiopeiae</span> Star in the constellation Cassiopeia

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<span class="mw-page-title-main">IK Tauri</span> Mira variable star in the constellation Taurus

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<span class="mw-page-title-main">T Leporis</span> Star in the constellation Lepus

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References

  1. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  2. "GCVS Query=W Hya". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia . Retrieved 2012-08-22.
  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. 1 2 "V* W Hya". SIMBAD Astronomical Database. Retrieved 2012-08-21.
  5. 1 2 Vlemmings, W. H. T.; Van Langevelde, H. J.; Diamond, P. J.; Habing, H. J.; Schilizzi, R. T. (2003). "VLBI astrometry of circumstellar OH masers: Proper motions and parallaxes of four AGB stars". Astronomy & Astrophysics. 407: 213–224. arXiv: astro-ph/0305405 . Bibcode:2003A&A...407..213V. doi:10.1051/0004-6361:20030766. S2CID   11505142.
  6. 1 2 3 Takeuti, Mine; Nakagawa, Akiharu; Kurayama, Tomoharu; Honma, Mareki (2013). "A Method to Estimate the Masses of Asymptotic Giant Branch Variable Stars". Publications of the Astronomical Society of Japan. 65 (3): 60. Bibcode:2013PASJ...65...60T. doi: 10.1093/pasj/65.3.60 .
  7. Ohnaka, K.; Wong, K. T.; Weigelt, G.; Hofmann, K.-H. (November 2024). "Contemporaneous high-angular-resolution imaging of the AGB star W Hya in vibrationally excited H 2 O lines and visible polarized light with ALMA and VLT/SPHERE-ZIMPOL". Astronomy & Astrophysics. 691: L14. doi:10.1051/0004-6361/202451977. ISSN   0004-6361.
  8. Zubko & Elitzur, Moshe (2000). "Water and Dust Emission from W Hydrae". The Astrophysical Journal . 544 (2): 137–140. arXiv: astro-ph/0009440 . Bibcode:2000ApJ...544L.137Z. doi:10.1086/317317. S2CID   17702515.