3 Equulei

{{Short description|K-type giant star in the constellation Equuleus}}

{{Starbox begin

| name = 3 Equulei

}}

{{Starbox image

| image=

{{Location mark

|image=Equuleus constellation map.svg|alt=|float=center|width=240

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=3 Equulei

|x=594|y=690

}}

|caption=Location of 3 Equulei (circled)

}}

{{Starbox observe

| epoch = J2000

| ra = {{RA|21|04|34.65147}}

| dec = {{DEC|+5|30|10.3032}}

| appmag_v = 5.593

| constell = Equuleus

}}

{{Starbox character

| class = K5 III

| b-v = +1.651

| u-b = +1.934

| variable =

}}

{{Starbox astrometry

| radial_v = {{nowrap|–15.26 ± 0.2}}

| prop_mo_ra = +13.15

| prop_mo_dec = +0.66

| parallax = 4.24

| p_error = 0.42

| parallax_footnote =

| absmag_v = –1.02

}}

{{Starbox detail

| mass =

| radius = 63

| luminosity = 949

| temperature = 3,893

| metal_fe =

| gravity =

| rotational_velocity = 4.6

| age_gyr =

}}

{{Starbox catalog

| names = ζ Equ, 3 Equ, BD+04° 4606, HD 200644, HIP 104031, HR 8066, SAO 126518.

}}

{{Starbox reference

| Simbad = 3+Equ

}}

3 Equulei is a single star located in the small northern constellation of Equuleus. It is faintly visible to the naked eye at an apparent visual magnitude of 5.6. Based upon an annual parallax shift of 4.24 mas, 3 Equulei is roughly {{Convert|770|ly|pc|abbr=off|lk=on}} distant from Earth, give or take an 80 light-year margin of error. At that distance, the apparent brightness of the star is diminished by 0.15 in visual magnitude because of extinction from interstellar gas and dust.

3 Equulei has been referred to in some sources as ζ (Zeta) Equulei, although it was not given that designation by Bayer.

Properties

3 Equulei is an evolved giant star with a stellar classification of K5 III. The measured angular diameter of this star, after correction for limb darkening, is {{nowrap|2.44 ± 0.03 mas}}. At the estimated distance of 770 light-years, this yields a physical size of about 63 times the radius of the Sun. It is radiating an estimated 949 times the luminosity of the Sun from this expanded outer envelope at an effective temperature of 3,893 K. At this heat, it shines with the orange-hued glow of a K-type star.

References

{{reflist|refs=

{{cite journal | bibcode=1995yCat.5050....0H | title=VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991) | journal=VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H | volume=5050 | last1=Hoffleit | first1=D. | last2=Warren | first2=W. H. | year=1995 }}

{{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 | postscript=. |arxiv = 0708.1752 | s2cid=18759600 }}

{{citation | display-authors=1 | last1=Famaey | first1=B. | last2=Jorissen | first2=A. | last3=Luri | first3=X. | last4=Mayor | first4=M. | last5=Udry | first5=S. | last6=Dejonghe | first6=H. | last7=Turon | first7=C. | title=Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters | journal=Astronomy and Astrophysics | volume=430 | issue=1 | pages=165–186 |date=January 2005 | doi=10.1051/0004-6361:20041272 | bibcode=2005A&A...430..165F | arxiv=astro-ph/0409579 | s2cid=17804304 | postscript=. }}

{{citation | last1=Cousins | first1=A. W. J. | title=Standardization of Broadband Photometry of Equatorial Standards | journal=South African Astronomical Observatory Circulars | volume=8 | page=59 | year=1984 | bibcode=1984SAAOC...8...59C | postscript=. }}

{{citation | last1=Soubiran | first1=C. | last2=Le Campion | first2=J.-F. | last3=Cayrel de Strobel | first3=G. | last4=Caillo | first4=A. | title=The PASTEL catalogue of stellar parameters | journal=Astronomy and Astrophysics | volume=515 | page=A111 |date=June 2010 | doi=10.1051/0004-6361/201014247 | bibcode=2010A&A...515A.111S | postscript=. |arxiv = 1004.1069 | s2cid=118362423 }}

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

{{citation | 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 | volume=431 | pages=773–777 |date=February 2005 | issue=2 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}

{{citation | first1=Kenneth R. | last1=Lang | title=Astrophysical formulae | volume=1 | series=Astronomy and astrophysics library | edition=3 | publisher=Birkhäuser | year=2006 | isbn=3-540-29692-1 | url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 }}. The radius (R_*) is given by:

: $\begin{align} 2\cdot R_*
& = \frac{(240\cdot 2.44\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
& \approx 126\cdot R_{\bigodot}
\end{align}$

{{citation | last1=Ryon | first1=Jenna | last2=Shetrone | first2=Matthew D. | last3=Smith | first3=Graeme H. | title=Comparing the Ca ii H and K Emission Lines in Red Giant Stars | journal=Publications of the Astronomical Society of the Pacific | volume=121 | issue=882 | pages=842–856 |date=August 2009 | doi=10.1086/605456 | bibcode=2009PASP..121..842R | postscript=. |arxiv = 0907.3346 | s2cid=17821279 }}

{{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=2012-07-21 | postscript=. | archive-url=https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | archive-date=March 18, 2012 | url-status=dead }}

{{citation | display-authors=1 | last1=Henry | first1=Gregory W. | last2=Fekel | first2=Francis C. | last3=Henry | first3=Stephen M. | last4=Hall | first4=Douglas S. | title=Photometric Variability in a Sample of 187 G and K Giants | journal=The Astrophysical Journal Supplement Series | volume=130 | issue=1 | pages=201–225 |date=September 2000 | doi=10.1086/317346 | bibcode=2000ApJS..130..201H | postscript=. | citeseerx=10.1.1.40.8526 | s2cid=17160805 }}

}}

External links

http://frostydrew.org/stars.dc/star/id-126518/pss-obsy/

Category:Equuleus

Category:K-type giants

Equulei, Zeta

Equulei, 03

Category:Durchmusterung objects

200644

8066

104031