25 Aquarii

{{short description|Single, K-type star in the constellation Aquarius}}

{{Starbox begin

| name = 25 Aquarii

}}

{{Starbox image

| image=

{{Location mark

|image=Aquarius constellation map.svg|alt=|float=center|width=260

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=25 Aquarii

|x=676|y=254

}}

|caption=Location of 25 Aquarii (circled)

}}

{{Starbox observe

| epoch = J2000

| constell = Aquarius

| ra = {{RA|21|39|33.26719}}

| dec = {{DEC|+02|14|36.8193}}

| appmag_v = +5.09

}}

{{Starbox character

| type = red clump

| class = K0 III

| b-v = +1.032

| u-b = +0.90

| variable =

}}

{{Starbox astrometry

| radial_v = {{val|-34.63|0.11}}

| prop_mo_ra = −30.179

| prop_mo_dec = −83.636

| parallax = 13.2155

| p_error = 0.0892

| parallax_footnote =

| absmag_v = +0.768

}}

{{Starbox detail

| mass = 3.0

| radius = 11

| luminosity = 54

| temperature = 4,721

| metal_fe = −0.17

| gravity = 2.67

| rotational_velocity = 2.5

| age_myr = 377

}}

{{Starbox catalog

| names = d Aquarii, 25 Aqr, 6 Pegasi, BD+01 4517, FK5 3729, HD 206067, HIP 106944, HR 8277, SAO 126965

}}

{{Starbox reference

| Simbad = 25+Aqr

}}

25 Aquarii (abbreviated 25 Aqr) is a single star in the equatorial constellation of Aquarius. 25 Aquarii is the modern Flamsteed designation; in the past it held the designation 6 Pegasi. It also bears the Bayer designation of d Aquarii. It is located near the border with the modern Pegasus constellation. Although faint at an apparent visual magnitude of +5.09, it is bright enough to be viewed from suburban skies. Based upon an annual parallax shift of {{val|0.0132|ul=arcseconds}}, it is located at a distance of around {{Convert|247|ly|pc|abbr=off|lk=on}} from Earth. The visual magnitude of the star is diminished by 0.09 from extinction caused by intervening gas and dust.

The spectrum of this star matches a stellar classification of K0 III, with the luminosity class of III indicating that this is a giant star that has evolved away from the main sequence after exhausting the supply of hydrogen at its core. It belongs to a population known as clump giants and hence is generating energy through the nuclear fusion of helium at the core. The outer envelope has expanded to 11 times the radius of the Sun and it is radiating 54 times the Sun's luminosity. This energy is being emitted from the stellar atmosphere at an effective temperature of {{val|fmt=commas|4,721|ul=K}}, causing it to glow with the orange hue of a K-type star.

References

{{reflist|refs=

{{citation |postscript=. |bibcode=2008A&A...480...91S |title=Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants |last1=Soubiran |first1=C. |last2=Bienaymé |first2=O. |last3=Mishenina |first3=T. V. |last4=Kovtyukh |first4=V. V. |journal=Astronomy and Astrophysics |date=2008 |volume=480 |issue=1 |page=91 |doi=10.1051/0004-6361:20078788 |arxiv=0712.1370 }}

{{citation | last=Wagman | first=M. | title=Flamsteed's Missing Stars | journal=Journal for the History of Astronomy | issue=3 | volume=18 | page=220 | bibcode=1987JHA....18..209W | postscript=. |date=August 1987 | doi=10.1177/002182868701800305| s2cid=118445625 }}

{{citation | 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 | doi=10.1088/0004-6256/135/1/209 | bibcode=2008AJ....135..209M | postscript=. |date=January 2008| doi-access=free }}

{{citation | last1=Argue | first1=A. N. | title=UBV photometry of 550 F, G and K type stars | journal=Monthly Notices of the Royal Astronomical Society | volume=133 | pages=475–493 | year=1966 | issue=4 | bibcode=1966MNRAS.133..475A | postscript=. | doi=10.1093/mnras/133.4.475| doi-access=free }}

{{cite simbad | title=* d Aqr | access-date=2012-07-13 | mode=cs2 | postscript=. }}

{{citation | postscript=. | 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 | doi=10.1111/j.1365-2966.2008.13596.x | bibcode=2008MNRAS.389..869E |arxiv = 0806.2878 |date=September 2008| doi-access=free | s2cid=14878976 }}

{{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 | pages=165–186 | doi=10.1051/0004-6361:20041272 | bibcode=2005A&A...430..165F | arxiv=astro-ph/0409579 | postscript=. |date=January 2005| s2cid=17804304 }}

{{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 |postscript=. |url-status=dead |archive-url=https://web.archive.org/web/20120222183238/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archive-date=February 22, 2012 }}

{{citation | last1=Alves | first1=David R. | title=K-Band Calibration of the Red Clump Luminosity | journal=The Astrophysical Journal | volume=539 | issue=2 | pages=732–741 | doi=10.1086/309278 | bibcode=2000ApJ...539..732A | postscript=. |arxiv = astro-ph/0003329 |date=August 2000| s2cid=16673121 }}

}}

External links

[http://aladin.u-strasbg.fr/AladinPreview?-c=21+39+33.2658%2B02+14+36.810&ident=*+d+Aqr&submit=Aladin+previewer Image 25 Aquarii]

Category:K-type giants

Category:Horizontal-branch stars

Category:Aquarius (constellation)