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Nu Hydrae

{{Short description|Star in the constellation Hydra}}

{{Starbox begin}}

{{Starbox image

| image =

{{Location mark

| image=Hydra IAU.svg

| float=center | width=280 | position=right

| mark=Red circle.svg | mark_width=10 | mark_link=ν Hya

| x%=55.6 | y%=46.1

}}

| caption=Location of ν Hydrae (circled)

}}

{{Starbox observe

| epoch = J2000

| constell = Hydra

| ra = {{RA|10|49|37.48875}}

| dec = {{DEC|-16|11|37.1360}}

| appmag_v = 3.115

}}

{{Starbox character

| type =

| class = K0/K1 III

| b-v = +1.239

| u-b = +1.305

| variable =

}}

{{Starbox astrometry

| radial_v = {{val|−1.37|0.25}}

| prop_mo_ra = +93.35

| prop_mo_dec = +198.88

| parallax = 23.7940

| p_error = 0.1695

| parallax_footnote ={{cite Gaia EDR3|3557567320183657472}}

| absmag_v = −0.11

}}

{{Starbox detail

| mass = 2.0

| radius = 21

| luminosity = 151

| temperature = 4,335

| metal_fe = −0.30

| rotation =

| rotational_velocity = 5.3

| gravity = 2.3

| age =

}}

{{Starbox catalog

| names = {{odlist | B=ν Hya | F=4 Crateris | BD=−15 3138 | FK5=410 | HD=93813 | HIP=52943 | HR=4232 | SAO=156256 }}

}}

{{Starbox reference

| Simbad = nu+Hya

}}

{{Starbox end}}

Nu Hydrae, Latinized from ν Hydrae, is an orange-hued star in the constellation Hydra, near the border with the neighboring constellation of Crater. It has an apparent visual magnitude of 3.115, which is bright enough to be seen with the naked eye. Based upon parallax measurements, this star is located at a distance of about {{Convert|137|ly|pc|abbr=off|lk=on}} from the Earth.

The spectrum of this star matches a stellar classification of K0/K1 III, where the luminosity class of 'III' indicates this is a giant star that has exhausted the supply of hydrogen at its core and evolved away from the main sequence. The radius of this star has expanded to 21 times the Sun's radius and it radiates about 151 times the luminosity of the Sun. This expanded outer envelope has an effective temperature of about 4,335 K, giving it the characteristic orange hue of a K-type star.

Nu Hydrae is an X-ray emitter with an estimated luminosity of {{nowrap|6.6 × 1028 erg s−1}} in the X-ray band. The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is about half that in the Sun.{{efn|name=metal}} It has a relatively high proper motion across the celestial sphere, suggesting that it has a peculiar velocity roughly three times higher than its neighbors.

Nu Hydrae was a later designation of 4 Crateris.{{cite journal

| last=Wagman | first=M.

| title=Flamsteed's Missing Stars

| journal=Journal for the History of Astronomy |issue=3 | volume=18 | page=215 |date=August 1987

| bibcode=1987JHA....18..209W | doi=10.1177/002182868701800305| s2cid=118445625

}}

Notes

{{notelist|refs=

{{efn| name=metal|1=The actual abundance of metals relative to the abundance in the Sun can be derived by taking the metallicity estimate to the power of ten, thus:

: 10[Fe/H] = 10−0.30 ≈ 0.50}}

}}

References

{{Reflist|40em|refs=

{{citation | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}

{{cite journal | display-authors=1 | last1=Massarotti | first1=Alessandro | last2=Latham | first2=David W. | last3=Stefanik | first3=Robert P. | last4=Fogel | first4=Jeffrey | title=Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity | journal=The Astronomical Journal | volume=135 | issue=1 | pages=209–231 |date=January 2008 | doi=10.1088/0004-6256/135/1/209 | bibcode=2008AJ....135..209M | doi-access=free }}

{{cite XHIP|52943|mode=cs2|postscript=.}}

{{citation | display-authors=1 | last1=Gutierrez-Moreno | first1=Adelina | last2=Moreno | first2=H. | last3=Stock | first3=J. | last4=Torres | first4=C. | last5=Wroblewski | first5=H. | title=A System of photometric standards | journal=Publications of the Department of Astronomy University of Chile | publisher=Publicaciones Universidad de Chile, Department de Astronomy | volume=1 | pages=1–17 | year=1966 | bibcode=1966PDAUC...1....1G }}

{{citation | last1=Gondoin | first1=P. | title=Evolution of X-ray activity and rotation on G-K giants | journal=Astronomy and Astrophysics | volume=352 | pages=217–227 |date=December 1999 | bibcode=1999A&A...352..217G }}

{{citation | last1=di Benedetto | first1=G. P. | title=Towards a fundamental calibration of stellar parameters of A, F, G, K dwarfs and giants | journal=Astronomy and Astrophysics | volume=339 | pages=858–871 |date=November 1998 | bibcode=1998A&A...339..858D }}

{{citation | first1=James B. | last1=Kaler | title=Nu Hydrae | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/nuhya.html | access-date=2012-01-13 }}

{{citation | title=LTT 3973 -- High proper-motion Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+93813 | access-date=2012-01-13 }}

{{citation | title=The Colour of Stars | date=December 21, 2004 | work=Australia Telescope, Outreach and Education | publisher=Commonwealth Scientific and Industrial Research Organisation | url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | access-date=2012-01-16 | archive-url=https://web.archive.org/web/20131203222826/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | archive-date=December 3, 2013 | url-status=dead }}

}}

{{Stars of Hydra}}

{{DEFAULTSORT:Nu Hydrae}}

Category:K-type giants

Category:Hydra (constellation)

Hydrae, Nu

Category:Durchmusterung objects

Crateris, 04

093813

052943

4232