W Hydrae

W Hydrae
Observation data Epoch J2000.0 Equinox J2000.0
Constellation	Hydra
Right ascension	13^h 49^m 01.998^s
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

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

↑ "GCVS Query=W Hya". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22.
1 2 "V* W Hya". SIMBAD Astronomical Database. Retrieved 2012-08-21.
1 2 3 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.

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

External links

AAVSO Variable Star of the Month. April 2008: W Hya
W Hya at AAVSO (chart #8585EPX)

Stars of Hydra

Bayer	α (Alphard) β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ τ¹ τ² υ¹ υ² φ¹ φ² φ³ χ¹ χ² ψ ω

Flamsteed	1 2 3 6 9 10 12 14 15 17 19 20 21 23 24 25 26 27 28 29 33 34 37 44 47 48 50 51 52 54 55 56 57 58 59 60 17 Crt 14 Lib 30 Mon 31 Mon 2 Sex

Variable	R S U V W X RT RW RX SX SZ TT TW VX VZ WZ AI AV CT DF EX EZ FG GK HQ HS II IL IY KU KZ LN LO LQ LR LV LX MO MX NS OY QT V335 V355 V406 V419 V478

HR	3212 3269 3271 3272 3285 3288 3295 3305 3338 3342 3374 3378 3383 3392 3411 3446 3458 3478 3480 3486 3493 3526 3529 3538 3554 3557 3564 3578 3584 3590 3596 3636 3638 3649 3651 3653 3675 3687 3704 3714 3741 3749 3750 3758 3760 3762 3763 3767 3772 3785 3788 3794 3796 3801 3802 3805 3808 3810 3822 3848 3858 3862 3908 3919 3921 3923 3931 3963 3965 3977 3986 3988 3991 4005 4011 4055 4068 4071 4076 4117 4123 4130 4149 4152 4157 4158 4162 4172 4190 4214 (3 Crt) 4225 4251 (6 Crt) 4261 4282 4298 4302 (8 Crt) 4307 4328 4331 4334 (10 Crt) 4339 4346 4373 4445 4449 (18 Crt) 4458 (20 Crt) 4469 (22 Crt) 4473 (23 Crt) 4498 4503 (26 Crt) 4525 4542 4548 4553 4558 4565 (29 Crt) 4579 4612 4628 4651 4723 4735 4774 4803 4810 4839 4857 4860 4918 4978 5090 5097 5098 5120 5128 5166 5167 5197 5209 5228 5246 5265 5309 5314 5324 5356 5399 5565

HD	68667 72659 74156 74685 75098 75217 76027 76478 78614 79481 79994 82943 83352 86226 86264 88806 90156 94046 (5 Crt) 97344 105113 106500 107869 117033 121758 125279

Gliese	Gliese 357 Gliese 433 Gliese 453 GJ 2066 GJ 3517 GJ 3634

Other	BD -3 2525 BD-22 3467 CE 315 EC 14026-2647 HAT-P-35 HAT-P-42 HE 1327-2326 IRC -20197 Kelu-1 LHS 2065 LHS 3003 2MASS 0835-08 2MASS 1114-2618 PSR B0820+02 PSR B0834+06 TWA 5 WASP-15 WASP-25 WASP-36 WISE 0855−0714

List

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