| 释义 |
- References
{{Starbox begin
| name = Rho Hydrae
}}{{Starbox observe
| epoch = J2000.0
| equinox = J2000.0 (ICRS)
| constell = Hydra
| ra = {{RA|08|48|25.97057}}
| dec = {{DEC|+05|50|16.1283}}
| appmag_v = 4.34[3]
}}{{Starbox character
| class = A0 Vn[4]
| b-v = −0.04[3]
| u-b = −0.04[3]
| r-i =
| variable =
}}{{Starbox astrometry
| radial_v = +32.8[7]
| prop_mo_ra = −17.33
| prop_mo_dec = −29.41
| parallax = 9.21
| p_error = 0.21
| parallax_footnote =
| absmag_v = −0.83[11]
}}{{Starbox detail
| source = [4]
| mass = {{Val|3.24|0.05}}
| radius = 2.0[13]
| luminosity = 242
| temperature = 9,795
| gravity =
| metal_fe =
| rotational_velocity = 128
| age_myr = 350[14]
}}{{Starbox catalog
| names = ρ Hya, 13 Hya, BD+06° 2040, HD 75137, HIP 43234, HR 3492, SAO 117146.[15]
}}{{Starbox reference
| Simbad = rho+Hya
}}{{starbox end}}Rho Hydrae, Latinized from ρ Hydrae, is a binary star[16] in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 4.34.[3] This system forms part of the ring-shaped asterism that represents the head of the hydra constellation.[18] The distance to this system, based upon an annual parallax shift of 9.21 mas,[ is about 354 light years. At that distance, the visual magnitude is diminished by an interstellar extinction factor of 0.06, due to intervening dust.[14]]The primary component is an A-type main sequence star with a stellar classification of A0 Vn.[4] It has around double[13] the radius of the Sun and 3.2 times the Sun's mass. Rho Hydrae is around 350[14] million years old and has a high rate of spin, with a projected rotational velocity of 128 km/s. It radiates 242 times the solar luminosity from its outer atmosphere at an effective temperature of 9,795 K.[4] The companion is a magnitude 11.9 star at an angular separation of 12.1 arc seconds along a position angle of 146°, as of 2000.[25] References1. ^1 {{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | postscript=. }}
2. ^1 2 {{citation | last1=Pasinetti Fracassini | first1=L. E. | last2=Pastori | first2=L. | last3=Covino | first3=S. | last4=Pozzi | first4=A. | title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) | journal=Astronomy and Astrophysics | display-authors=1 | volume=367 | pages=521–524 | date=February 2001 | edition=3rd | doi=10.1051/0004-6361:20000451 | bibcode=2001A&A...367..521P | arxiv=astro-ph/0012289 | postscript=. }}
3. ^1 {{citation | display-authors=1 | last1=Mason | first1=B. D. | last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I. | last4=Douglass | first4=G. G. | last5=Worley | first5=C. E. | title=The Washington Visual Double Star Catalog | year=2014 | bibcode=2001AJ....122.3466M | doi=10.1086/323920 | postscript=. | volume=122 | journal=The Astronomical Journal | pages=3466–3471}}
4. ^1 {{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 | date=September 2008 | doi=10.1111/j.1365-2966.2008.13596.x | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | postscript=. }}
5. ^1 {{citation | title=Burnham's Celestial Handbook | series=An Observer's Guide to the Universe Beyond the Solar System | first1=Robert | last1=Burnham | postscript=. | publisher=Courier Corporation | volume=2 | year=2013 | isbn=0486317935 | page=1014 | url=https://books.google.com/books?id=aLbDAgAAQBAJ&pg=PA1014 }}
6. ^1 2 3 {{citation | title=Spatial distribution and kinematics of OB stars | last1=Gontcharov | first1=G. A. | journal=Astronomy Letters | volume=38 | issue=11 | pages=694–706 | date=November 2012 | doi=10.1134/S1063773712110035 | bibcode=2012AstL...38..694G | arxiv=1606.09028 | postscript=. }}
7. ^1 {{citation | last=Wilson | first=Ralph Elmer | year=1953 | title=General Catalogue of Stellar Radial Velocities | publisher=Carnegie Institution of Washington | location=Washington | bibcode=1953GCRV..C......0W | postscript=. }}
8. ^1 2 3 4 {{citation | last1=Zorec | first1=J. | last2=Royer | first2=F. | title=Rotational velocities of A-type stars. IV. Evolution of rotational velocities | journal=Astronomy & Astrophysics | volume=537 | page=A120 |date=January 2012 | doi=10.1051/0004-6361/201117691 | bibcode=2012A&A...537A.120Z | arxiv=1201.2052 | postscript=. }}
9. ^1 2 3 4 {{citation | last1=Mermilliod | first1=J.-C. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | year=1986 | publisher=SIMBAD | bibcode=1986EgUBV........0M | postscript=. }}
10. ^1 {{cite simbad | title=rho Hya | accessdate=2017-01-08 | postscript=. }}
[1][2][3][4][5][6][7][8][9][10]
}}{{Stars of Hydra|state=collapsed}} 9 : A-type main-sequence stars|Binary stars|Hydra (constellation)|Bayer objects|Durchmusterung objects|Flamsteed objects|Henry Draper Catalogue objects|Hipparcos objects|HR objects |