W Hydrae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
W Hydrae
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[1]
Characteristics
Spectral type M7.5IIIe
Apparent magnitude (J) -1.7[2]
Variable type Mira-type
Astrometry
Parallax (π) 9.59 ± 1.12 mas
Distance 374.9 ly
(115 pc)
Details
Mass >1 M
Radius 562 R
Luminosity 11,050[3] L
Temperature 2,500[3] K
Other designations
V* W Hya, GCRV 8148, JP11 2429, YZ 118 8744BDS 6635 A, GSC 06728-00019, 2MASS J13490199-2822034, [LFO93] 1346-28, CCDM J13491-2822A, HD 120285, PPM 262109, [PCC93] 155CD-27 9429, HIC 67419, RAFGL 1650, [WCP90] 134612.033-280709.09, CPD-27 4792, HIP 67419, SAO 181981, AAVSO 1343-27, FAUST 3909, IDS 13434-2752 A, SKY# 25345, FK5 5220, IRAS 13462-2807, SRS 11878, GC 18659, IRC -30207, TYC 6728-19-1.

W Hydrae is a Mira-type variable star in the constellation Hydra. The star is nearly located within the Solar neighborhood, between 75 and 120 parsecs, likely at 375 light years from Sun. 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,[2] is the 7th brightest star in the night sky, and is even brighter than Sirius.

Water and dust masers[edit]

The star also shows signs of intense water emissions, indicative of the presence of a wide disk of dust and water vapour.[3] 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).

References[edit]

  1. ^ "GCVS Query=W Hya". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22. 
  2. ^ a b "V* W Hya". SIMBAD Astronomical Database. Retrieved 2012-08-21. 
  3. ^ a b c Zubko & Elitzur; 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. 

Coordinates: Sky map 13h 49m 01.998s, +28° 22′ 03.49″

External links[edit]