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 the 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]