eta Columbae

{{Starbox begin

| name = η Columbae

}}

{{Starbox observe

| epoch = J2000.0

| equinox = J2000.0 (ICRS)

| constell = Columba

| ra = {{RA|05|59|08.80519}}

| dec = {{DEC|−42|48|54.4822}}

| appmag_v = 3.96

}}

{{Starbox character

| class = G8/K1 II or K0 III

| b-v = +1.14

| u-b = +1.08

| r-i =

| variable =

}}

{{Starbox astrometry

| radial_v = +17.0

| prop_mo_ra = +18.39

| prop_mo_dec = −10.87

| parallax = 6.91

| p_error = 0.12

| parallax_footnote =

| absmag_v = −2.10

}}

{{Starbox detail

| source =

| mass = 3.33

| radius = 38.6

| luminosity = 708

| temperature = {{Val|4620|54|fmt=commas}}

| gravity = 1.72

| metal_fe = −0.01

| rotational_velocity =

| age_myr =

}}

{{Starbox catalog

| names = η Col, CD−42° 2266, FK5 229, HD 40808, HIP 28328, HR 2120, SAO 217650.

}}

{{Starbox reference

| Simbad = eta+Col

}}

Eta Columbae is a solitary star near the southern boundary of the constellation Columba. It is visible to the naked eye, having an apparent visual magnitude of 3.96. Based upon an annual parallax shift of 6.91 mas, it lies at a distance of roughly 472 light years from the Sun.

This is an orange-hued K-type giant star with a stellar classification of K0 III, or possibly a bright giant with a crossover class of G8/K1 II. The measured angular diameter of this star, after correction for limb darkening, is {{val|2.48|0.03|u=mas}}. At the estimated distance of this star, this yields a physical size of about 38.6 times the radius of the Sun. It has an estimated 3.33 times the mass of the Sun and radiates 708 times the solar luminosity from its outer atmosphere at an effective temperature of 4,620 K.

References

{{reflist|refs=

{{citation

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| last1=van Leeuwen | first1=F.

| journal=Astronomy and Astrophysics

| volume=474 | issue=2 | pages=653–664 | date=2007

| arxiv=0708.1752 | bibcode=2007A&A...474..653V

| doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}

{{citation

| title=Ultraviolet Emission Lines in BA and Non-BA Giants

| display-authors=1 | last1=Böhm-Vitense | first1=Erika

| last2=Carpenter | first2=Kenneth G. | last3=Robinson | first3=Richard D.

| journal=The Astrophysical Journal | postscript=.

| volume=545 | issue=2 | pages=992–999 | date=December 2000

| doi=10.1086/317850 | bibcode=2000ApJ...545..992B | doi-access= }}

{{citation

| title=Viewing the Constellations with Binoculars: 250+ Wonderful Sky Objects to See and Explore

| series=The Patrick Moore Practical Astronomy Series

| first1=Bojan | last1=Kambic |postscript=.

| publisher=Springer Science & Business Media

| year=2009 | isbn=978-0387853550 | page=260

| url=https://books.google.com/books?id=3vxLNPNHOcwC&pg=PA260 }}

{{citation

| display-authors=1 | last1=Richichi | first1=A.

| last2=Percheron | first2=I. | last3=Khristoforova | first3=M.

| title=CHARM2: An updated Catalog of High Angular Resolution Measurements

| journal=Astronomy and Astrophysics | postscript=.

| volume=431 | issue=2 | pages=773–777 | date=February 2005

| doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}

{{citation

| first1=Kenneth R. | last1=Lang | year=2006

| title=Astrophysical formulae | volume=1 | postscript=.

| series=Astronomy and astrophysics library

| edition=3rd | publisher=Birkhäuser | isbn=3-540-29692-1

| url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41

}} The radius (R_*) is given by:

: $\begin{align} 2\cdot R_*
& = \frac{(144.7\cdot 2.48\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
& \approx 77.2\cdot R_{\bigodot}
\end{align}$

{{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 | doi-access=free | bibcode=2008MNRAS.389..869E

| arxiv=0806.2878 | s2cid=14878976 | postscript=. }}

{{cite journal

| last1=Luck | first1=R. Earle

| title=Abundances in the Local Region. I. G and K Giants

| journal=The Astronomical Journal

| volume=150 | issue=3 | pages=88 | year=2015