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{{Short description|Star in the constellation Corona Borealis}}{{distinguish|S Coronae Borealis}} | |||
{{Starbox begin|title=Sigma Coronae Borealis}} | {{Starbox begin|title=Sigma Coronae Borealis}} | ||
{{Starbox image | |||
| image = ] | |||
| caption = A ] for TZ Coronae Borealis, plotted from ] data<ref name=MAST/> | |||
⚫ | }} | ||
{{Starbox observe 3s | {{Starbox observe 3s | ||
|epoch=] | |epoch=] | ||
|constell=] | |constell=] | ||
|component1=σ<sup>2</sup> |
|component1=σ CrB A (σ<sup>2</sup>) | ||
|ra1={{RA|16|14|40.854}}<ref name=TYC2>{{cite journal|title=The Tycho-2 catalogue of the 2.5 million brightest stars|author=Høg, E.|display-authors=etal|date=2000|journal=Astronomy and Astrophysics|volume=355|pages=L27–L30|bibcode=2000A&A...355L..27H}}</ref> | |ra1={{RA|16|14|40.854}}<ref name=TYC2>{{cite journal|title=The Tycho-2 catalogue of the 2.5 million brightest stars|author=Høg, E.|display-authors=etal|date=2000|journal=Astronomy and Astrophysics|volume=355|pages=L27–L30|bibcode=2000A&A...355L..27H}}</ref> | ||
|dec1={{DEC|+33|51|31.02}}<ref name=TYC2/> | |dec1={{DEC|+33|51|31.02}}<ref name=TYC2/> | ||
|appmag_v1=5.55<ref name=TYC2/> | |appmag_v1=5.55<ref name=TYC2/> | ||
|component2=σ<sup>1</sup> |
|component2=σ CrB B (σ<sup>1</sup>) | ||
|ra2={{RA|16|14|40.394}}<ref name=TYC2/> | |ra2={{RA|16|14|40.394}}<ref name=TYC2/> | ||
|dec2={{DEC|+33|51|27.05}}<ref name=TYC2/> | |dec2={{DEC|+33|51|27.05}}<ref name=TYC2/> | ||
|appmag_v2=6.419<ref name=TYC2/> | |appmag_v2=6.419<ref name=TYC2/> | ||
|component3=σ CrB C | |component3=σ CrB C | ||
|ra3={{RA|16|13|56.26666}}<ref name=HIP>{{cite journal|title=Validation of the new Hipparcos reduction|url=http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL|author=van Leeuwen, F.|display-authors=etal|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}}</ref> | |ra3={{RA|16|13|56.26666}}<ref name=HIP>{{cite journal|title=Validation of the new Hipparcos reduction|url=http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL|author=van Leeuwen, F.|display-authors=etal|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}}</ref> | ||
|dec3={{DEC|+33|46|24.2953}}<ref name=HIP/> | |dec3={{DEC|+33|46|24.2953}}<ref name=HIP/> | ||
|appmag_v3=12.229<ref name=UCAC4>{{cite journal|author=Zacharias, N.|display-authors=etal|title=The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)|journal=VizieR On-line Data Catalog|volume=1322 |
|appmag_v3=12.229<ref name=UCAC4>{{cite journal|author=Zacharias, N.|display-authors=etal|title=The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)|journal=VizieR On-line Data Catalog|volume=1322|date=2012|bibcode=2012yCat.1322....0Z}}</ref> | ||
}} | }} | ||
{{Starbox character | {{Starbox character | ||
| |
|component1=σ CrB | ||
|class=F6V (A)<ref name=Strassmeier>{{cite journal|title=Chromospheric activity in G and K giants: the spectroscopic data base|author=Strassmeier, K. G.|journal=Astronomy and Astrophysics Supplement|volume=103|number=103|pages=413–425|bibcode=1994A&AS..103..413S|date=1994}}</ref> + G1V (B)<ref name=Gray>{{cite journal|bibcode=2003AJ....126.2048G|doi=10.1086/378365|arxiv=astro-ph/0308182|title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I|journal=The Astronomical Journal|volume=126|issue=4|pages=2048|year=2003|last1=Gray|first1=R. O.|last2=Corbally|first2=C. J.|last3=Garrison|first3=R. F.|last4=McFadden|first4=M. T.|last5=Robinson|first5=P. E.}}</ref> | |class=F6V (A)<ref name=Strassmeier>{{cite journal|title=Chromospheric activity in G and K giants: the spectroscopic data base|author=Strassmeier, K. G.|journal=Astronomy and Astrophysics Supplement|volume=103|number=103|pages=413–425|bibcode=1994A&AS..103..413S|date=1994}}</ref> + G1V (B)<ref name=Gray>{{cite journal|bibcode=2003AJ....126.2048G|doi=10.1086/378365|arxiv=astro-ph/0308182|title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I|journal=The Astronomical Journal|volume=126|issue=4|pages=2048|year=2003|last1=Gray|first1=R. O.|last2=Corbally|first2=C. J.|last3=Garrison|first3=R. F.|last4=McFadden|first4=M. T.|last5=Robinson|first5=P. E.|s2cid=119417105}}</ref> | ||
|b-v=+0.599<ref name=UBV>{{cite journal|title=Photometric and astrometric observations of close visual binaries|author1=Rakos, K. D.|author2=Albrecht, R.|author3=Jenkner, H.|author4=Kreidl, T.|author5=Michalke, R.|author6=Oberlerchner, D.|author7=Santos, E.|author8=Schermann, A.|author9=Schnell, A.|author10=Weiss, W.|journal=Astronomy and Astrophysics Supplement Series|volume=47|issue=221–235|pages=221|date=1982|bibcode=1982A&AS...47..221R}}</ref> | |b-v=+0.599<ref name=UBV>{{cite journal|title=Photometric and astrometric observations of close visual binaries|author1=Rakos, K. D.|author2=Albrecht, R.|author3=Jenkner, H.|author4=Kreidl, T.|author5=Michalke, R.|author6=Oberlerchner, D.|author7=Santos, E.|author8=Schermann, A.|author9=Schnell, A.|author10=Weiss, W.|journal=Astronomy and Astrophysics Supplement Series|volume=47|issue=221–235|pages=221|date=1982|bibcode=1982A&AS...47..221R}}</ref> | ||
|u-b=+0.045<ref name=UBV/> | |u-b=+0.045<ref name=UBV/> | ||
|variable=]<ref name=SimbadAB/> | |variable=]<ref name=SimbadAB/> | ||
⚫ | |component2=σ CrB C | ||
⚫ | }} | ||
⚫ | |class2=M2.5V<ref name=Reid>{{cite journal|doi=10.1086/117655|bibcode=1995AJ....110.1838R|title=The Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs -Bandstrengths and Kinematics|journal=The Astronomical Journal|volume=110|pages=1838|year=1995|last1=Reid|first1=I. Neill|last2=Hawley|first2=Suzanne L.|last3=Gizis|first3=John E.|doi-access=free}}</ref> | ||
⚫ | {{Starbox |
||
|component=σ CrB C | |||
⚫ | | |
||
}} | }} | ||
{{Starbox astrometry | {{Starbox astrometry | ||
|component1=σ CrB |
|component1=σ CrB A | ||
|radial_v=−12.30 ± 0.06<ref name=Karatas>{{cite journal|doi=10.1111/j.1365-2966.2004.07588.x| |
|radial_v=−12.30 ± 0.06<ref name=Karatas>{{cite journal |doi=10.1111/j.1365-2966.2004.07588.x | ||
| title=Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution | journal=Monthly Notices of the Royal Astronomical Society | |||
| volume=349 | issue=3 | pages=1069–1092 | |||
| bibcode=2004MNRAS.349.1069K |arxiv = astro-ph/0404219 | last1=Karataș | |||
| first1=Yüksel | |||
| last2=Bilir |first2=Selçuk | |||
| last3=Eker |first3=Zeki | |||
| last4=Demircan |first4=Osman | |||
| last5=Liebert |first5=James | |||
⚫ | |prop_mo_ra= |
||
| last6=Hawley |first6=Suzanne L. | |||
⚫ | |prop_mo_dec= |
||
| last7=Fraser |first7=Oliver J. | |||
⚫ | |parallax= |
||
| last8=Covey |first8=Kevin R. | |||
⚫ | |p_error=0. |
||
| last9=Lowrance |first9=Patrick | |||
|parallax_footnote=<ref name=Lestrade>{{cite journal|bibcode=1999A&A...344.1014L|title=High-precision VLBI astrometry of radio-emitting stars|journal=Astronomy and Astrophysics|volume=344|pages=1014|author1=Lestrade|first1=J.-F.|last2=Preston|first2=R. A.|last3=Jones|first3=D. L.|last4=Phillips|first4=R. B.|last5=Rogers|first5=A. E. E.|last6=Titus|first6=M. A.|last7=Rioja|first7=M. J.|last8=Gabuzda|first8=D. C.|year=1999}}</ref> | |||
| last10=Kirkpatrick |first10=J. Davy | |||
⚫ | |absmag_v=4.64 ± 0.01 (σ<sup>1</sup> CrB)<br>4.35 ± 0.02 (σ<sup>2</sup> CrB |
||
| last11=Burgasser |first11=Adam J. | |||
⚫ | |component2=σ CrB C | ||
| year=2004 | |||
⚫ | | |
||
| doi-access=free | s2cid=15290475 | |||
⚫ | |prop_mo_ra2= |
||
}}</ref> | |||
⚫ | |prop_mo_dec2= |
||
|prop_mo_ra=−268.325<ref name=dr2a/> | |||
⚫ | |parallax2= |
||
|prop_mo_dec=−86.925<ref name=dr2a/> | |||
⚫ | |p_error2= |
||
⚫ | |parallax=44.1346 | ||
⚫ | |parallax_footnote2=<ref name= |
||
⚫ | |p_error=0.0644 | ||
|absmag_v2= | |||
|parallax_footnote=<ref name=dr2a>{{cite DR2|1328866562170960512}}</ref> | |||
⚫ | |component2=σ CrB B | ||
|radial_v2=−12.30 ± 0.06<ref name=Karatas/> | |||
⚫ | |prop_mo_ra2=−291.118<ref name=dr2b/> | ||
⚫ | |prop_mo_dec2=−78.651<ref name=dr2b/> | ||
⚫ | |parallax2=44.1475 | ||
⚫ | |p_error2=0.0237 | ||
⚫ | |parallax_footnote2=<ref name=dr2b>{{cite DR2|1328866562170960384}}</ref> | ||
⚫ | <!--|absmag_v=4.64 ± 0.01 (σ<sup>1</sup> CrB)<br/>4.35 ± 0.02 (σ<sup>2</sup> CrB primary)<br/>4.74 ± 0.02 (σ<sup>2</sup> CrB secondary)--> | ||
}} | |||
⚫ | {{Starbox astrometry|no_heading=y | ||
|component1=σ CrB C | |||
⚫ | |radial_v=−16.30 ± 10<ref name=Hawley>{{cite journal|bibcode=1996AJ....112.2799H|doi=10.1086/118222|title=The Palomar/MSU Nearby Star Spectroscopic Survey.II.The Southern M Dwarfs and Investigation of Magnetic Activity|journal=The Astronomical Journal|volume=112|pages=2799|year=1996|last1=Hawley|first1=Suzanne L.|last2=Gizis|first2=John E.|last3=Reid|first3=I. Neill}}</ref> | ||
⚫ | |prop_mo_ra=−265.92<ref name=HIP/> | ||
⚫ | |prop_mo_dec=−83.63<ref name=HIP/> | ||
|parallax=42.8557 | |||
|p_error=0.3965 | |||
|parallax_footnote=<ref name=dr2c>{{cite DR2|1322906861255829376}}</ref> | |||
|absmag_v= | |||
}} | }} | ||
{{Starbox orbit | {{Starbox orbit | ||
|reference=<ref name=Raghavan>{{cite journal|bibcode=2009ApJ...690..394R|doi=10.1088/0004-637X/690/1/394|arxiv=0808.4015|title=The Visual Orbit of the 1.1-day Spectroscopic Binary σ<sup>2</sup> Coronae Borealis from Interferometry at the CHARA Array|journal=The Astrophysical Journal|volume=690|pages= |
|reference=<ref name=Raghavan>{{cite journal|bibcode=2009ApJ...690..394R|doi=10.1088/0004-637X/690/1/394|arxiv=0808.4015|title=The Visual Orbit of the 1.1-day Spectroscopic Binary σ<sup>2</sup> Coronae Borealis from Interferometry at the CHARA Array|journal=The Astrophysical Journal|volume=690|issue=1|pages=394–406|year=2009|last1=Raghavan|first1=Deepak|last2=McAlister|first2=Harold A.|last3=Torres|first3=Guillermo|last4=Latham|first4=David W.|last5=Mason|first5=Brian D.|last6=Boyajian|first6=Tabetha S.|last7=Baines|first7=Ellyn K.|last8=Williams|first8=Stephen J.|last9=Brummelaar|first9=Theo A. ten|last10=Farrington|first10=Chris D.|last11=Ridgway|first11=Stephen T.|last12=Sturmann|first12=Laszlo|last13=Sturmann|first13=Judit|last14=Turner|first14=Nils H.|s2cid=14638405}}</ref> | ||
|primary=σ<sup>2</sup> CrB |
|primary=σ<sup>2</sup> CrB primary | ||
|name=σ<sup>2</sup> CrB |
|name=σ<sup>2</sup> CrB secondary | ||
|period_unitless=1.139791423(80) | |period_unitless=1.139791423(80) | ||
|axis_unitless=1.225 ± 0.013 mas | |axis_unitless=1.225 ± 0.013 mas | ||
Line 67: | Line 96: | ||
|node=28.0 ± 0.5 | |node=28.0 ± 0.5 | ||
|periastron=] 1825.2 ± 1.5 | |periastron=] 1825.2 ± 1.5 | ||
| |
|periarg_primary=237.3 ± 6.8 | ||
}} | }} | ||
{{Starbox orbit | {{Starbox orbit | ||
Line 93: | Line 122: | ||
}} | }} | ||
{{Starbox detail|no_heading=y | {{Starbox detail|no_heading=y | ||
|component1=σ<sup>2</sup> CrB |
|component1=σ<sup>2</sup> CrB primary | ||
|mass=1.137 ± 0.037<ref name=Raghavan/> | |mass=1.137 ± 0.037<ref name=Raghavan/> | ||
|radius=1.244 ± 0.050<ref name=Raghavan/> | |radius=1.244 ± 0.050<ref name=Raghavan/> | ||
Line 101: | Line 130: | ||
|gravity=4.5<ref name=Raghavan/> | |gravity=4.5<ref name=Raghavan/> | ||
|luminosity= | |luminosity= | ||
| |
|age_gyr=0.5 to 1.5<ref name=Raghavan/> | ||
|component2=σ<sup>2</sup> CrB |
|component2=σ<sup>2</sup> CrB secondary | ||
|mass2=1.090 ± 0.036<ref name=Raghavan/> | |||
|mass2= | |||
|radius2= | |radius2=1.244 ± 0.050<ref name=Raghavan/> | ||
|temperature2= | |temperature2=5870 ± 150<ref name=Raghavan/> | ||
|rotational_velocity2=26 ± 1<ref name=Raghavan/> | |rotational_velocity2=26 ± 1<ref name=Raghavan/> | ||
|metal_fe2=0.0<ref name=Raghavan/> | |metal_fe2=0.0<ref name=Raghavan/> | ||
|gravity2=4.5<ref name=Raghavan/> | |gravity2=4.5<ref name=Raghavan/> | ||
|luminosity2= | |luminosity2= | ||
| |
|age_gyr2=0.5 to 1.5<ref name=Raghavan/> | ||
}} | }} | ||
{{Starbox detail|no_heading=y | {{Starbox detail|no_heading=y | ||
|component1=σ CrB C | |component1=σ CrB C | ||
|mass=0.423 ± 0.042<ref name=Mann>{{cite journal|bibcode=2015ApJ...804...64M|arxiv=1501.01635|doi=10.1088/0004-637X/804/1/64}}</ref><!-- not the theoretical values --> | |mass=0.423 ± 0.042<ref name=Mann>{{cite journal|bibcode=2015ApJ...804...64M|arxiv=1501.01635|doi=10.1088/0004-637X/804/1/64|title=How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius|author1=Mann, Andrew W.|author2=Feiden, Gregory A.|author3=Gaidos, Eric|author4=Boyajian, Tabetha|author5=von Braun, Kaspar|journal=The Astrophysical Journal|volume=804|issue=1|pages=38|date=2015|s2cid=19269312}}</ref><!-- not the theoretical values --> | ||
|radius=0.437 ± 0.020<ref name=Mann/> | |radius=0.437 ± 0.020<ref name=Mann/> | ||
|temperature=3454 ± 63<ref name=Mann/> | |temperature=3454 ± 63<ref name=Mann/> | ||
|metal_fe=−0.06 ± 0.03<ref name=Mann/> | |metal_fe=−0.06 ± 0.03<ref name=Mann/> | ||
|gravity=5.0<ref name=Lepine>{{cite journal|title=A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky|author=Lépine, S.|display-authors=etal|date=2013|journal=The Astronomical Journal|volume=145|issue=4|bibcode=2013AJ....145..102L|doi=10.1088/0004-6256/145/4/102|arxiv=1206.5991}}</ref> | |gravity=5.0<ref name=Lepine>{{cite journal|title=A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky|author=Lépine, S.|display-authors=etal|date=2013|journal=The Astronomical Journal|volume=145|issue=4|pages=102|bibcode=2013AJ....145..102L|doi=10.1088/0004-6256/145/4/102|arxiv=1206.5991|s2cid=117144290}}</ref> | ||
|age_gyr=2.95<ref name=Mann/><!-- 10^(9.47 ± 0.58) --> | |age_gyr=2.95<ref name=Mann/><!-- 10^(9.47 ± 0.58) --> | ||
}} | }} | ||
{{Starbox catalog | {{Starbox catalog | ||
|names={{odlist|ADS=9979 |
|names={{odlist|ADS=9979|B=σ CrB|F=17 CrB|BD=+34° 2750|HIP=79607 (only AB)|SAO=65165}}<ref name=SimbadAB>{{cite simbad|title=* sig CrB|access-date=20 April 2017}}</ref> | ||
|component1=σ |
|component1=σ CrB A | ||
|names1={{odlist| |
|names1={{odlist|B=σ<sup>2</sup> CrB|V=TZ CrB|HR=6064|HD=146361|GJ=9550B|TYC=2583-1846-1|WDS=J16147+3352A|CCDM=J16147+3352A}}<ref name=Simbad2>{{cite simbad|title=* sig02 CrB|access-date=20 April 2017}}</ref> | ||
|component2=σ |
|component2=σ CrB B | ||
|names2={{odlist|TYC=2583-1846- |
|names2={{odlist|B=σ<sup>1</sup> CrB|HR=6063|HD=146362|GJ=9550A|TYC=2583-1846-2|WDS=J16147+3352B|CCDM=J16147+3352B}}<ref name=Simbad1>{{cite simbad|title=* sig01 CrB|access-date=20 April 2017}}</ref> | ||
|component3=σ CrB C | |component3=σ CrB C | ||
|names3={{odlist|GJ=9549|G=180-42|HIP=79551| |
|names3={{odlist|GJ=9549|G=180-42|HIP=79551|WDS=J16147+3352E}}<ref name=SimbadC>{{cite simbad|title=* sig CrB C|access-date=20 April 2017}}</ref> | ||
}} | }} | ||
{{Starbox reference | {{Starbox reference | ||
|Simbad=sig+CrB|sn=σ CrB | |Simbad=sig+CrB|sn=σ CrB | ||
|Simbad2= |
|Simbad2=HD+146361A|sn2=σ<sup>1</sup> CrB | ||
|Simbad3= |
|Simbad3=HD+146362|sn3=σ<sup>2</sup> CrB | ||
|Simbad4=sig+CrB+C|sn4=σ CrB C | |Simbad4=sig+CrB+C|sn4=σ CrB C | ||
|ARICNS=01274|an=σ<sup>1</sup> CrB | |ARICNS=01274|an=σ<sup>1</sup> CrB | ||
Line 140: | Line 169: | ||
}} | }} | ||
{{Starbox end}} | {{Starbox end}} | ||
⚫ | '''Sigma Coronae Borealis''' ('''σ CrB''') is a ] in the ] of ]. It is a quintuple ] containing three sunlike ]s and two other low-mass stars. | ||
⚫ | '''Sigma Coronae Borealis''' ('''σ CrB''') is a ] in the ] of ]. It is a quintuple ] containing three sunlike ]s and two other low-mass stars. The combined ] is 5.3 and the system lies 74 light years from Earth. σ CrB A is the ] '''TZ Coronae Borealis'''. | ||
==Components== | |||
The brightest components of Sigma Coronae Borealis form a visual ] and are designated Sigma<sup>1</sup> Corona Borealis and Sigma<sup>2</sup> Corona Borealis, also known as Sigma Corona Borealis B<ref name=Simbad1/> and Sigma Corona Borealis A,<ref name=Simbad2/> respectively. (Sigma<sup>2</sup> Corona Borealis received the designation ''A'' because it is the brighter component.) Sigma<sup>1</sup> Corona Borealis is a ] like the ], and has similar parameters: a mass roughly equal to that of the Sun, and an ] of 5950 ].<ref name=Raghavan/> A visual ] for Sigma<sup>1</sup> and Sigma<sup>2</sup> Corona Borealis has been calculated, with an ] of about 730 years and a high ] of 0.72.<ref name=Raghavan/> | |||
==System components== | |||
⚫ | Sigma<sup>2</sup> Corona Borealis itself is a close binary. Here, the two stars are extremely close and orbit fairly quickly, every 1.14 days.<ref name=Raghavan/> This tiny separation of only 0.0279 ]<ref name=Raghavan/> has allowed the two stars to exert ]s on each other, leading to synchronization of their rotation. They have also been classified as ]s (RS CVn)—young, active stars that show variability in their apparent magnitude due to ]s on their surfaces |
||
The brightest components of Sigma Coronae Borealis form a visual ] with an angular separation of 7 arcsecond first resolved in the 19th century,<ref name=wds>{{cite journal|bibcode=2001AJ....122.3466M|title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog|journal=The Astronomical Journal|volume=122|issue=6|pages=3466|last1=Mason|first1=Brian D.|last2=Wycoff|first2=Gary L.|last3=Hartkopf|first3=William I.|last4=Douglass|first4=Geoffrey G.|last5=Worley|first5=Charles E.|year=2001|doi=10.1086/323920|doi-access=free}}</ref> and are designated σ Corona Borealis A and B. More recently, the designations σ<sup>2</sup> and σ<sup>1</sup> Corona Borealis have come into use. Somewhat confusingly, the brighter component A is referred to as σ<sup>2</sup> because it has the higher ]. A third component, while being separated by {{val|635|ul="}} (translating to a minimum distance of 14,000 au), has a similar parallax and ] to the brighter stars and is physically associated. It is known in the ] (WDS), a compilation of observations of double stars, as component E,<ref name=wds/> but it is usually called Sigma Coronae Borealis C.<ref name=Raghavan/> | |||
Sigma<sup>1</sup> Corona Borealis is a ] like the ], and has similar parameters: a mass roughly equal to that of the Sun, and an ] of 5950 ].<ref name=Raghavan/> A visual ] has been calculated, with a ] of about 730 years and a high ] of 0.72.<ref name=Raghavan/> | |||
⚫ | Sigma<sup>2</sup> Corona Borealis itself is a close binary. Here, the two stars are extremely close and orbit fairly quickly, every 1.14 days.<ref name=Raghavan/> This tiny separation of only 0.0279 ]<ref name=Raghavan/> has allowed the two stars to exert ]s on each other, leading to synchronization of their rotation. They have also been classified as ]s (RS CVn)—young, active stars that show variability in their apparent magnitude due to ]s on their surfaces.<ref name=SimbadAB/> | ||
⚫ | |||
Despite Sigma<sup>2</sup> Corona Borealis's two stars being separated only by about the diameter of each star, they were ] using the ] ] at the ]. As of 2006, it is the shortest-period binary ever to be resolved. The primary is 13.7% more massive than the Sun, while the secondary is 9.0% more massive than the Sun, and both are 24.4% wider than the Sun.<ref name=Raghavan/> | |||
⚫ | σ Coronae Borealis C, also known as HIP 79551, appears as a ] with a ] of M2.5V.<ref name=Reid/> It too is a binary star, with a companion in a 52-year orbit. The companion has a mass of {{solar mass|0.10}} and has been detected through ].<ref name=Heintz>{{cite journal|doi=10.1086/115340|bibcode=1990AJ.....99..420H|title=Photographic astrometry of binary and proper-motion stars|journal=The Astronomical Journal|volume=99|pages=420|year=1990|last1=Heintz|first1=W. D.}}</ref><ref name=Raghavan/> | ||
==Optical companions== | ==Optical companions== | ||
The ] (WDS), a compilation of observations of double stars, lists several components to the main system. Two of those are listed in the WDS as components C, and D. As of 1984, component C was separated from the primary by 18 |
The ] (WDS), a compilation of observations of double stars, lists several components to the main system. Two of those are listed in the WDS as components C, and D. As of 1984, component C was separated from the primary by {{val|18|u="}} along a ] of 103° and as of 1996, component D was separated from the primary by {{val|88|u="}} along a ] of 82°. However, both of them have different ]s through space and are not related, just optical alignments.<ref name=wds/> | ||
== |
==Variability== | ||
The spectroscopic binary σ<sup>2</sup> CrB is an ]. It varies in brightness by 0.05 magnitudes every 1.139789 days, the same as the orbital period. The brightness changes are caused by variations in surface brightness on the stars, effectively giant sunspots. ]s are not given to stars with ]s, but in this case only one component of σ Coronae Borealis is identified as variable, so it has the designation TZ Coronae Borealis.<ref name=ibvs>{{cite journal|bibcode=1981IBVS.1921....1K|title=65th Name-List of Variable Stars|journal=Information Bulletin on Variable Stars|volume=1921|pages=1|last1=Kholopov|first1=P. N.|last2=Samus'|first2=N. N.|last3=Kukarkina|first3=N. P.|last4=Medvedeva|first4=G. I.|last5=Perova|first5=N. B.|year=1981}}</ref> | |||
⚫ | {{reflist |
||
==See also== | ==See also== | ||
*], |
*], another quintuple containing an RS CVn binary | ||
==References== | |||
⚫ | {{reflist|refs= | ||
<ref name=MAST>{{cite web |title=MAST: Barbara A. Mikulski Archive for Space Telescopes |url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html |publisher=Space Telescope Science Institute |access-date=8 December 2021}}</ref> | |||
}} | |||
==External links== | ==External links== | ||
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Latest revision as of 20:59, 22 August 2024
Star in the constellation Corona BorealisNot to be confused with S Coronae Borealis.A light curve for TZ Coronae Borealis, plotted from TESS data | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Corona Borealis |
σ CrB A (σ) | |
Right ascension | 16 14 40.854 |
Declination | +33° 51′ 31.02″ |
Apparent magnitude (V) | 5.55 |
σ CrB B (σ) | |
Right ascension | 16 14 40.394 |
Declination | +33° 51′ 27.05″ |
Apparent magnitude (V) | 6.419 |
σ CrB C | |
Right ascension | 16 13 56.26666 |
Declination | +33° 46′ 24.2953″ |
Apparent magnitude (V) | 12.229 |
Characteristics | |
σ CrB | |
Spectral type | F6V (A) + G1V (B) |
U−B color index | +0.045 |
B−V color index | +0.599 |
Variable type | RS CVn |
σ CrB C | |
Spectral type | M2.5V |
Astrometry | |
σ CrB A | |
Radial velocity (Rv) | −12.30 ± 0.06 km/s |
Proper motion (μ) | RA: −268.325 mas/yr Dec.: −86.925 mas/yr |
Parallax (π) | 44.1346 ± 0.0644 mas |
Distance | 73.9 ± 0.1 ly (22.66 ± 0.03 pc) |
σ CrB B | |
Radial velocity (Rv) | −12.30 ± 0.06 km/s |
Proper motion (μ) | RA: −291.118 mas/yr Dec.: −78.651 mas/yr |
Parallax (π) | 44.1475 ± 0.0237 mas |
Distance | 73.88 ± 0.04 ly (22.65 ± 0.01 pc) |
σ CrB C | |
Radial velocity (Rv) | −16.30 ± 10 km/s |
Proper motion (μ) | RA: −265.92 mas/yr Dec.: −83.63 mas/yr |
Parallax (π) | 42.8557 ± 0.3965 mas |
Distance | 76.1 ± 0.7 ly (23.3 ± 0.2 pc) |
Orbit | |
Primary | σ CrB primary |
Companion | σ CrB secondary |
Period (P) | 1.139791423(80) |
Semi-major axis (a) | 1.225 ± 0.013 mas |
Eccentricity (e) | 0.0 |
Inclination (i) | 28.08 ± 0.34° |
Longitude of the node (Ω) | 207.93 ± 0.67° |
Periastron epoch (T) | Tnode = 2450127.04855(20) |
Argument of periastron (ω) (secondary) | 0.0° |
Orbit | |
Primary | σ CrB |
Companion | σ CrB |
Period (P) | 726 ± 62 yr |
Semi-major axis (a) | 5.26 ± 0.35″ |
Eccentricity (e) | 0.72 ± 0.01 |
Inclination (i) | 32.3 ± 4.1° |
Longitude of the node (Ω) | 28.0 ± 0.5° |
Periastron epoch (T) | B 1825.2 ± 1.5 |
Argument of periastron (ω) (primary) | 237.3 ± 6.8° |
Orbit | |
Primary | σ CrB Ca |
Companion | σ CrB Cb |
Period (P) | 52 yr |
Semi-major axis (a) | 0.111″ |
Eccentricity (e) | 0.36 |
Inclination (i) | 59° |
Longitude of the node (Ω) | 30° |
Periastron epoch (T) | B 1963.0 |
Argument of periastron (ω) (secondary) | 127° |
Details | |
σ CrB | |
Mass | 1.0 M☉ |
Surface gravity (log g) | 4.5 cgs |
Temperature | 5950 ± 100 K |
Rotational velocity (v sin i) | 3 ± 2 km/s |
Age | 1 to 3 Myr |
σ CrB primary | |
Mass | 1.137 ± 0.037 M☉ |
Radius | 1.244 ± 0.050 R☉ |
Surface gravity (log g) | 4.5 cgs |
Temperature | 6050 ± 150 K |
Metallicity | 0.0 dex |
Rotational velocity (v sin i) | 26 ± 1 km/s |
Age | 0.5 to 1.5 Gyr |
σ CrB secondary | |
Mass | 1.090 ± 0.036 M☉ |
Radius | 1.244 ± 0.050 R☉ |
Surface gravity (log g) | 4.5 cgs |
Temperature | 5870 ± 150 K |
Metallicity | 0.0 dex |
Rotational velocity (v sin i) | 26 ± 1 km/s |
Age | 0.5 to 1.5 Gyr |
σ CrB C | |
Mass | 0.423 ± 0.042 M☉ |
Radius | 0.437 ± 0.020 R☉ |
Surface gravity (log g) | 5.0 cgs |
Temperature | 3454 ± 63 K |
Metallicity | −0.06 ± 0.03 dex |
Age | 2.95 Gyr |
Other designations | |
σ CrB, 17 CrB, BD+34° 2750, HIP 79607 (only AB), SAO 65165, ADS 9979 | |
σ CrB A: σ CrB, TZ CrB, GJ 9550B, HD 146361, HR 6064, CCDM J16147+3352A, WDS J16147+3352A, TYC 2583-1846-1 | |
σ CrB B: σ CrB, GJ 9550A, HD 146362, HR 6063, CCDM J16147+3352B, WDS J16147+3352B, TYC 2583-1846-2 | |
σ CrB C: GJ 9549, HIP 79551, WDS J16147+3352E, G 180-42 | |
Database references | |
SIMBAD | σ CrB |
σ CrB | |
σ CrB | |
σ CrB C | |
ARICNS | σ CrB |
σ CrB | |
σ CrB C |
Sigma Coronae Borealis (σ CrB) is a star system in the constellation of Corona Borealis. It is a quintuple star system containing three sunlike main-sequence stars and two other low-mass stars. The combined visual magnitude is 5.3 and the system lies 74 light years from Earth. σ CrB A is the variable star TZ Coronae Borealis.
System components
The brightest components of Sigma Coronae Borealis form a visual binary with an angular separation of 7 arcsecond first resolved in the 19th century, and are designated σ Corona Borealis A and B. More recently, the designations σ and σ Corona Borealis have come into use. Somewhat confusingly, the brighter component A is referred to as σ because it has the higher right ascension. A third component, while being separated by 635″ (translating to a minimum distance of 14,000 au), has a similar parallax and proper motion to the brighter stars and is physically associated. It is known in the Washington Double Star Catalog (WDS), a compilation of observations of double stars, as component E, but it is usually called Sigma Coronae Borealis C.
Sigma Corona Borealis is a G-type main-sequence star like the Sun, and has similar parameters: a mass roughly equal to that of the Sun, and an effective temperature of 5950 K. A visual orbit has been calculated, with a period of about 730 years and a high eccentricity of 0.72.
Sigma Corona Borealis itself is a close binary. Here, the two stars are extremely close and orbit fairly quickly, every 1.14 days. This tiny separation of only 0.0279 au has allowed the two stars to exert tidal forces on each other, leading to synchronization of their rotation. They have also been classified as RS Canum Venaticorum variables (RS CVn)—young, active stars that show variability in their apparent magnitude due to starspots on their surfaces.
Despite Sigma Corona Borealis's two stars being separated only by about the diameter of each star, they were resolved using the CHARA optical interferometer at the Mount Wilson Observatory. As of 2006, it is the shortest-period binary ever to be resolved. The primary is 13.7% more massive than the Sun, while the secondary is 9.0% more massive than the Sun, and both are 24.4% wider than the Sun.
σ Coronae Borealis C, also known as HIP 79551, appears as a red dwarf with a spectral type of M2.5V. It too is a binary star, with a companion in a 52-year orbit. The companion has a mass of 0.10 M☉ and has been detected through astrometry.
Optical companions
The Washington Double Star Catalog (WDS), a compilation of observations of double stars, lists several components to the main system. Two of those are listed in the WDS as components C, and D. As of 1984, component C was separated from the primary by 18″ along a position angle of 103° and as of 1996, component D was separated from the primary by 88″ along a position angle of 82°. However, both of them have different proper motions through space and are not related, just optical alignments.
Variability
The spectroscopic binary σ CrB is an RS Canum Venaticorum variable. It varies in brightness by 0.05 magnitudes every 1.139789 days, the same as the orbital period. The brightness changes are caused by variations in surface brightness on the stars, effectively giant sunspots. Variable star designations are not given to stars with Bayer designations, but in this case only one component of σ Coronae Borealis is identified as variable, so it has the designation TZ Coronae Borealis.
See also
- Xi Ursae Majoris, another quintuple containing an RS CVn binary
References
- "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- Zacharias, N.; et al. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog. 1322. Bibcode:2012yCat.1322....0Z.
- Strassmeier, K. G. (1994). "Chromospheric activity in G and K giants: the spectroscopic data base". Astronomy and Astrophysics Supplement. 103 (103): 413–425. Bibcode:1994A&AS..103..413S.
- Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal. 126 (4): 2048. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
- ^ Rakos, K. D.; Albrecht, R.; Jenkner, H.; Kreidl, T.; Michalke, R.; Oberlerchner, D.; Santos, E.; Schermann, A.; Schnell, A.; Weiss, W. (1982). "Photometric and astrometric observations of close visual binaries". Astronomy and Astrophysics Supplement Series. 47 (221–235): 221. Bibcode:1982A&AS...47..221R.
- ^ "* sig CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 April 2017.
- ^ Reid, I. Neill; Hawley, Suzanne L.; Gizis, John E. (1995). "The Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs -Bandstrengths and Kinematics". The Astronomical Journal. 110: 1838. Bibcode:1995AJ....110.1838R. doi:10.1086/117655.
- ^ Karataș, Yüksel; Bilir, Selçuk; Eker, Zeki; Demircan, Osman; Liebert, James; Hawley, Suzanne L.; Fraser, Oliver J.; Covey, Kevin R.; Lowrance, Patrick; Kirkpatrick, J. Davy; Burgasser, Adam J. (2004). "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution". Monthly Notices of the Royal Astronomical Society. 349 (3): 1069–1092. arXiv:astro-ph/0404219. Bibcode:2004MNRAS.349.1069K. doi:10.1111/j.1365-2966.2004.07588.x. S2CID 15290475.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- Hawley, Suzanne L.; Gizis, John E.; Reid, I. Neill (1996). "The Palomar/MSU Nearby Star Spectroscopic Survey.II.The Southern M Dwarfs and Investigation of Magnetic Activity". The Astronomical Journal. 112: 2799. Bibcode:1996AJ....112.2799H. doi:10.1086/118222.
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Raghavan, Deepak; McAlister, Harold A.; Torres, Guillermo; Latham, David W.; Mason, Brian D.; Boyajian, Tabetha S.; Baines, Ellyn K.; Williams, Stephen J.; Brummelaar, Theo A. ten; Farrington, Chris D.; Ridgway, Stephen T.; Sturmann, Laszlo; Sturmann, Judit; Turner, Nils H. (2009). "The Visual Orbit of the 1.1-day Spectroscopic Binary σ Coronae Borealis from Interferometry at the CHARA Array". The Astrophysical Journal. 690 (1): 394–406. arXiv:0808.4015. Bibcode:2009ApJ...690..394R. doi:10.1088/0004-637X/690/1/394. S2CID 14638405.
- ^ Heintz, W. D. (1990). "Photographic astrometry of binary and proper-motion stars". The Astronomical Journal. 99: 420. Bibcode:1990AJ.....99..420H. doi:10.1086/115340.
- ^ Mann, Andrew W.; Feiden, Gregory A.; Gaidos, Eric; Boyajian, Tabetha; von Braun, Kaspar (2015). "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius". The Astrophysical Journal. 804 (1): 38. arXiv:1501.01635. Bibcode:2015ApJ...804...64M. doi:10.1088/0004-637X/804/1/64. S2CID 19269312.
- Lépine, S.; et al. (2013). "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky". The Astronomical Journal. 145 (4): 102. arXiv:1206.5991. Bibcode:2013AJ....145..102L. doi:10.1088/0004-6256/145/4/102. S2CID 117144290.
- "* sig02 CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 April 2017.
- "* sig01 CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 April 2017.
- "* sig CrB C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 April 2017.
- ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
- Kholopov, P. N.; Samus', N. N.; Kukarkina, N. P.; Medvedeva, G. I.; Perova, N. B. (1981). "65th Name-List of Variable Stars". Information Bulletin on Variable Stars. 1921: 1. Bibcode:1981IBVS.1921....1K.
External links
- Kaler, James B. "Sigma Coronae Borealis". Stars. University of Illinois.
Constellation of Corona Borealis | |||||||||||
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Exoplanets |
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Galaxy clusters |
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- Corona Borealis
- Henry Draper Catalogue objects
- Bayer objects
- Objects with variable star designations
- Flamsteed objects
- Bright Star Catalogue objects
- F-type main-sequence stars
- G-type main-sequence stars
- Hipparcos objects
- Multiple star systems
- RS Canum Venaticorum variables
- Durchmusterung objects
- Gliese and GJ objects
- M-type main-sequence stars