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HD 122563

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

{{Starbox begin}}

{{Starbox observe

| epoch = J2000

| constell = Boötes

| ra = {{RA|14|02|31.84551}}

| dec = {{DEC|+09|41|09.9444}}

| appmag_v = 6.20

}}

{{Starbox character

| class = G8:III: Fe-5

| r-i = 0.58

| v-r = 0.50

| b-v = +0.90

| u-b = +0.38

| variable = Suspected[http://webviz.u-strasbg.fr/viz-bin/VizieR-S?NSV%206526 NSV 6526]

}}

{{Starbox astrometry

| radial_v = −26.39

| prop_mo_ra = −189.539

| prop_mo_dec = −70.415

| parallax = 3.0991

| p_error = 0.0332

| parallax_footnote =

| absmag_v = −0.69

}}

{{Starbox detail

| source =

| mass = {{val|0.77|0.05}}

| gravity = {{val|1.404|0.035}}

| metal_fe = {{val|-2.75|0.12}}

| luminosity = {{val|339|13}}

| temperature = {{val|4635|34|fmt=commas}}

| radius = {{val|28.86|0.63}}

| rotational_velocity = 5.0

| age_gyr = 12.6

}}

{{Starbox catalog

| names=BD+10°2617, HIP 68594, HD 122563, HR 5270, SAO 120251

}}

{{Starbox reference

| Simbad=HD122563

}}

{{Starbox end}}

HD 122563 is an extremely metal-poor red giant star, and the brightest known metal-poor star in the sky. Its low heavy element content was first recognized by spectroscopic analysis in 1963. For more than twenty years it was the most metal-poor star known, being more metal-poor than any known globular cluster, and it is the most accessible example of an extreme population II or Halo star.

As the most extreme metal-poor star known, HD 122563's composition was crucial in constraining theories for galactic chemical evolution; in particular, its composition peculiarities provided signposts for understanding the accumulation of heavy elements by stellar nucleosynthesis in the Galaxy. For example, it has an excess of oxygen, [O/Fe] = +0.6, while the proportions of strontium, yttrium, zirconium, barium and the lanthanide elements suggest that the s-process has made no contribution to the material present in the star: in HD 122563, all these elements are products of the r-process instead. The implication is that the star formed at a time and place where there had not been enough time for any previous generation of stars to have produced s-process elements, though there was r-process material present.

Spectral type

The spectral type of HD 122563 is one of characteristics which initially indicated its peculiarity. In the Bright Star Catalogue its spectral type is given as F8 IV, but its color index indicates a surface temperature much cooler than an F8 star should be. Because the spectral type of a star in the A to K star regime is judged by the relative strengths of the absorption lines of the metals relative to the hydrogen Balmer lines, the extreme metal deficiency results in weak metal lines and yields a spuriously early spectral type. If the spectral classification is performed including the metal deficiency, the result is a rather later type, G8:III: Fe-5.

References

{{reflist|refs=

{{cite Gaia DR3|3723554268436602240}}

{{Cite journal |last1=Karovicova |first1=I. |last2=White |first2=T. R. |last3=Nordlander |first3=T. |last4=Casagrande |first4=L. |last5=Ireland |first5=M. |last6=Huber |first6=D. |last7=Jofré |first7=P. |date=2020-08-01 |title=Fundamental stellar parameters of benchmark stars from CHARA interferometry - I. Metal-poor stars |url=https://www.aanda.org/articles/aa/full_html/2020/08/aa37590-20/aa37590-20.html |journal=Astronomy & Astrophysics |language=en |arxiv=2006.05411 |bibcode=2020A&A...640A..25K |volume=640 |pages=A25 |doi=10.1051/0004-6361/202037590 |issn=0004-6361}}

{{cite journal |bibcode=2006A&A...458..895D |title=A catalog of rotational and radial velocities for evolved stars. IV. Metal-poor stars^ |last1=De Medeiros |first1=J. R. |last2=Silva |first2=J. R. P. |last3=Do Nascimento |first3=J. D. |last4=Canto Martins |first4=B. L. |last5=Da Silva |first5=L. |last6=Melo |first6=C. |last7=Burnet |first7=M. |journal=Astronomy and Astrophysics |year=2006 |volume=458 |issue=3 |page=895 |doi=10.1051/0004-6361:20065642 |arxiv=astro-ph/0608248 |s2cid=54046583 }}

{{cite journal |bibcode=2012A&A...545A..17C |title=Fundamental properties of the Population II fiducial stars HD 122563 and GMB 1830 from CHARA interferometric observations |last1=Creevey |first1=O. L. |last2=Thévenin |first2=F. |last3=Boyajian |first3=T. S. |last4=Kervella |first4=P. |last5=Chiavassa |first5=A. |last6=Bigot |first6=L. |last7=Mérand |first7=A. |last8=Heiter |first8=U. |last9=Morel |first9=P. |last10=Pichon |first10=B. |last11=Mc Alister |first11=H. A. |last12=Ten Brummelaar |first12=T. A. |last13=Collet |first13=R. |last14=Van Belle |first14=G. T. |last15=Coudé Du Foresto |first15=V. |last16=Farrington |first16=C. |last17=Goldfinger |first17=P. J. |last18=Sturmann |first18=J. |last19=Sturmann |first19=L. |last20=Turner |first20=N. |journal=Astronomy and Astrophysics |year=2012 |volume=545 |pages=A17 |doi=10.1051/0004-6361/201219651 |arxiv=1207.5954 |s2cid=16387931 }}

{{cite journal | first1=P. | last1=Keenan | first2=R. | last2=McNeil |date=October 1989 | title = The Perkins catalog of revised MK types for the cooler stars | journal=Astrophysical Journal Supplement Series | volume=71 | pages=245–266 | bibcode=1989ApJS...71..245K | doi=10.1086/191373 }}

{{cite journal | display-authors=1 | last1=Bonifacio | first1=P. | last2=Spite | first2=M. | last3=Cayrel | first3=R. | last4=Hill | first4=V. | last5=Spite | first5=F. | last6=François | first6=P. | last7=Plez | first7=B. | last8=Ludwig | first8=H.-G. | last9=Caffau | first9=E. | last10=Molaro | first10=P. | last11=Depagne | first11=E. | last12=Andersen | first12=J. | last13=Barbuy | first13=B. | last14=Beers | first14=T. C. | last15=Nordström | first15=B. | last16=Primas | first16=F. | title=First stars XII. Abundances in extremely metal-poor turnoff stars, and comparison with the giants | journal=Astronomy and Astrophysics | volume=501 | issue=2 | pages=519–530 |date=July 2009 | doi=10.1051/0004-6361/200810610 | bibcode=2009A&A...501..519B |arxiv = 0903.4174 | s2cid=119164253 }}

{{cite journal | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | date=1966 | page=99 | bibcode=1966CoLPL...4...99J }}

{{cite journal | last1=Lambert | first1=D. L. | last2=Sneden | first2=C. | last3=Ries | first3=L. M. | title=The oxygen abundance in the metal-deficient star HD 122563 | journal=Astrophysical Journal | volume=188 | pages=97–100 | date=1974 | doi=10.1086/152690 | bibcode=1974ApJ...188...97L }}

{{cite journal | last1=Sneden | first1=C. | last2=Parthasarathy | first2=M. | title=The r- and s-process nuclei in the early history of the galaxy - HD 122563 | journal=Astrophysical Journal | volume=267 | pages=757–778 | date=1983 | doi=10.1086/160913 | bibcode=1983ApJ...267..757S | doi-access=free }}

{{cite journal | last1=Wallerstein | first1=G. | author1-link=George Wallerstein | last2=Greenstein | first2=J. L. | last3=Parker | first3=R. | last4=Helfer | first4=H. L. | last5=Aller | first5=L. H. | title=Red Giants with Extreme Metal Deficiencies | journal=Astrophysical Journal | volume=137 | pages=280–300 | date=1963 | doi=10.1086/147501 | bibcode=1963ApJ...137..280W | doi-access=free }}

{{cite journal |bibcode=2012AstL...38..331A |title=XHIP: An extended hipparcos compilation |last1=Anderson |first1=E. |last2=Francis |first2=Ch. |journal=Astronomy Letters |date=2012 |volume=38 |issue=5 |page=331 |doi=10.1134/S1063773712050015 |arxiv=1108.4971 }}

}}

External links

  • [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205270 HR 5270]
  • [http://aladin.u-strasbg.fr/AladinPreview?-c=14+02+31.8460%2B09+41+09.944&ident=NSV++6526&submit=Aladin+previewer Image HD 122563]

{{Stars of Boötes}}

122563

5270

Category:Boötes

068594

Category:G-type giants

Category:Population II stars

Category:Durchmusterung objects

Category:K-type subgiants