This Northern Crown

This Northern Crown
This Northern Crown
	Multiple star
	The place of a star in the constellation is indicated by an arrow and circled
Observational data; ( Age J2000.0 )
Type of	Multiple star
Right ascension
Declination
Distance	58.3 ± 0.8 St. years (17.9 ± 0.2 pc )
Visible magnitude ( V )	5.02
Constellation	Northern Crown
Astrometry
Radial velocity ( R v )	-7.410 ± 0.054 km / s
Own movement (μ)	RA: 116.83 ± 0.40 ; Dec: -171.37 ± 0.49
Parallax (π)	55.98 ± 0.78 mas
Characteristics
Spectral class	G1V / G3V / L8
Color Index ( B - V )	+ 0.56
physical characteristics
Weight	(A + B) 2.11 M ☉
Age	1–2.5 billion years
Temperature
Metallicity	-0.20
Elements of the orbit
Period ( P )	15 189.1 ± 2.9 days / 41.5 years
Semimajor axis ( a )	0.860 ± 0.003]] "
Eccentricity ( e )	0.277 ± 0.001
Inclination ( i )	58.7 ° ± 0.16 ° v
Node (Ω)	22.9 ° ± 0.19 °
Periastric Age ( T )	1892.317 ± 0.031
Pericenter Argument (ω)	39.24 ° ± 0.37
Other designations
	NSV 7054, STF 1937 ; Ba Eta Northern Crown, η Northern Crown, Eta Coronae Borealis, η Coronae Borealis, η CrB ; Fl 2 North Crown, 2 Coronae Borealis, 2 CrB ; BD +30 2653 , CCDM J15233 + 3018AB , HD 137107J , HIC 75312 , HIP 75312 , HR 5727/5728 , IRAS 15211 + 3027 , PPM 78550 , SAO 64673 , 2MASS J15231232 + 3017162, GC 20696, GCRV 8909, IDS 15191 + AB, LTT 14581, N30 3466, TD1 18202, UBV 13243, WDS J15232 + 3017AB
Database Information
SIMBAD	data
	The star has 3 components; Their parameters are presented below:

This Northern Crown , ( η Northern Crown, Eta Coronae Borealis, η Coronae Borealis ), abbreviation. Eta CrB, η CrB is a multiple star system in the constellation of Northern Corona . A star has a visible magnitude of +5.02 ^m ^[2] , and, according to the Bortl scale , is visible to the naked eye even in a bright suburban sky ( English Bright suburban sky ).

From parallax measurements obtained during the Hipparcos mission ^[1] , it is known that the star is removed by about 58.3 ± 0.8 sv. years ( 17.9 ± 0.2 pc ) from Earth . The star is observed north of 60 ° S , that is, it is visible almost throughout the Earth , with the exception of Antarctica . The best time to watch is May ^[17] .

This Northern Crown moves a little slower relative to the Sun than the other stars: its radial heliocentric speed: -7 km / s ^[17] , which is 1.4 times slower than the speed of local stars of the Galactic disk , and this also means that the star is approaching the Sun . The star itself moves north-east in the celestial sphere ^[18] .

At the moment, the star is resolved by five methods into five components. When naming these components, the Northern Crown designations A, B, C, D, and E are used in accordance with the convention used by the Washington Catalog of Visual Double Stars (WDS) and adopted by the International Astronomical Union (MAC) to designate star systems ^[15] .

Content

1 Properties of a multiple system
- 1.1 Component A
- 1.2 Component B
- 1.3 Component C
2 History of the study of the multiplicity of a star
3 Nearest star surroundings
4 notes
- 4.1 Comments
- 4.2 Sources
5 Links

Multiple System Properties

This Northern Crown’s telescope is visible as a pair of stars with a visible magnitude of +5.62 ^m ^[12] (component A) and +5.96 ^m ^[12] (component B). The third component C is visible only in infrared telescopes and has a visible magnitude of +17 ^m ^[15] . To a first approximation, This Northern Corona is a binary system in which two components rotate around a common center of mass , or barycenter , with a period of 41.6 years and a rather large eccentricity of 0.277 ^[3] . They revolve around a barycenter , at an angular distance of an average of at least 0.860 seconds of arc ^[3] , which is at a distance of 58.3 sv. years corresponds to the physical size of the semi-major axis 16.9 AU ^[12] . The stars then draw closer to a minimum distance of 12.2 AU (i.e. much further than the orbit where Saturn is located in the Solar System , whose distance to the Sun is 9.54 AU ), then they are removed at a maximum distance of 21.6 AU , (i.e., slightly farther than the orbit where Uranus is located in the Solar System , whose distance to the Sun is 19.22 AU ). The orbital inclination in the system of This Northern Corona is not very large - 58.7 ° ^[3] . Moreover, if we look at the Eta component of the Northern Corona B from the side of component A in the periastron (i.e., when the stars came close to a minimum distance), we will see a star with a visible magnitude of -21.53 ^m , i.e. about 114 times fainter than our Sun , with the star’s angular diameter being 0.04 ° ^[b] (that is, 12.5 times smaller than our Sun , whose angular diameter is 0.5 °). If we look at the Eta component of the Northern Corona B from the side of component A in the apoaster (i.e., when the stars have fallen to the maximum distance), then we will see a star with a visible magnitude of -20.29 ^m , i.e. about 356 times fainter than our Sun , and the angular diameter of the star would be 0.02 ° ^[b] (that is, 25 times smaller than our Sun ). Since the radii of the stars are almost the same, the same can be said about the component of This Northern Crown A.

This Northern Crown’s age is estimated at 1–2.5 billion ^[7] .

The star experiences a slight variability, in which its brightness rises to 4.94 ^m ^[19] . The period of variability is approximately equal to the period of rotation of stars, i.e. about 14 days and is most likely associated with stains on the surface of stars.

The star may belong to the moving group of Ursa Major stars , and even possibly to the Sirius supercluster ^[17] .

Component A

This Northern Crown A is a dwarf of spectral class G2V ^[11] , which indicates that the hydrogen in the star’s core serves as nuclear “fuel”, that is, the star is on the main sequence . A star radiates energy from its external atmosphere at an effective temperature of about 6062 K ^[11] , which gives it the characteristic yellow color of a star of spectral class G ^[18] .

The mass of the star is slightly larger than the solar one and amounts to: 1.19 $M_{\bigodot }$ ${\ displaystyle M _ {\ bigodot}}$ ^[3] . Its radius is slightly larger than the radius of the Sun and is 1.03 $R_{\bigodot }$ ${\ displaystyle R _ {\ bigodot}}$ ^[12] . Also, the star is almost twice brighter than our Sun , its luminosity is 1.71 $L_{\bigodot }$ ${\ displaystyle L _ {\ bigodot}}$ ^[12] . In order for a planet similar to our Earth to receive about the same amount of energy as it receives from the Sun, it would have to be placed at a distance of 1.31 AU , i.e. slightly less than the distance where Mars is located in the Solar System , whose major semi-axis is 1.52 AU Moreover, from such a distance, This Northern Corona A would look almost 16% smaller than our Sun , as we see it from the Earth - 0.42 ° (the angular diameter of our Sun is 0.5 °) ^[b] .

The star has a surface gravity of 4.47 GHS ^[11] or 295 1 m / s ² , that is, slightly more than on the Sun ( 274.0 m / s ² ). Stars with planets tend to be more metallic than the Sun, but This Northern Corona A has practically the same metallicity as the Sun: its iron content relative to hydrogen is 98% ^[11] of the solar value. The rotation speed of the star is about 3 km / s ^[9] , which gives the period of rotation of the star about 17 days.

Component B

This Northern Crown B is a star of the spectral class G2V ^[13] . The mass of the star is 1.05 $M_{\bigodot }$ ${\ displaystyle M _ {\ bigodot}}$ ^[3] and the radius is 0.98 $R_{\bigodot }$ ${\ displaystyle R _ {\ bigodot}}$ ^[12] . Also, the star is slightly brighter than our Sun , its luminosity is 1.25 $L_{\bigodot }$ ${\ displaystyle L _ {\ bigodot}}$ ^[12] .

The star has a surface gravity of 4.15 GHS ^[11] or 141 3 m / s ² , that is, much less solar ( 274.0 m / s ² ). Stars with planets tend to be more metallic than the Sun, but This Northern Corona B has almost the same metallicity as the Sun: its iron content relative to hydrogen is 85% ^[13] of the solar value.

In order for a planet similar to our Earth to receive about the same amount of energy as it receives from the Sun, it would have to be placed at a distance of about 1.18 AU , i.e. a little further than the orbit where our Earth is in the solar system . Moreover, from such a distance, This Northern Crown B would look 6% smaller than our Sun , as we see it from the Earth - 0.47 ° ^[12] (the angular diameter of our Sun is 0.5 °).

Component C

Companion C, a brown dwarf, was discovered in 2001 . The source 2MASSW J1523226 + 301456 in the working database 2MASS was identified as having a similar proper motion with the double star Eta of the Northern Crown AB, and subsequent observations confirmed its connection with the Eta system of the Northern Crown AB. It was discovered that the new component, This Northern Crown C, has a spectral type L8. The brown dwarf is removed at a minimum distance of 3600 AU , and, given the age of the system, the so-called “Cooling age” 1–2.5 billion ^[7] , it is possible to calculate the mass of a brown dwarf, which is 0.06 ± 0.015 $M_{\bigodot }$ ${\ displaystyle M _ {\ bigodot}}$ or 63 ± 16 M _J ^[7] . A star radiates energy from its external atmosphere at an effective temperature of about 1500 K ^[14] . The star has a surface gravity of 5.5 GHS ^[14] or 3162.28 m / s ² , that is, an order of magnitude larger than the solar ( 274.0 m / s ² ), which is apparently due to the small radius of the star. This Northern Corona C has a low metallicity : the iron content in it relative to hydrogen is [Fe / H = -0.20] or 63% of the solar value. There is evidence that this object has a variable spectrum, which can be attributed to inhomogeneous regions on its surface that enter and leave the field of view due to rotation ^[20]

The history of the study of the multiplicity of stars

The duality of the star was discovered in 1826 by V.Ya. Struve (component AB) and the star entered catalogs as STF1937 ^[c] . In 1856, the triple star was discovered (component AB-C). In 1879, four-time races were opened (component AB-D). Then, in 2000, the AB-E component was discovered, a brown dwarf with almost the same parallax ^[14] as the AB pair. According to the Washington catalog of visual binary stars , the parameters of these components are given in table ^[2] ^[15] :

Component	Year	Number of measurements	Position angle	Angular distance	Visible magnitude of 1 component	Visible magnitude 2 component
Ab	1826	1078	-	-	5.64 ^m	5.95 ^m
AB-C	1856	8	26 °	48.6 ″	5.02 ^m	13.35 ^m
	1984		0 °	69.2 ″
	2006		359 °	73.7 ″
AB-D	1879	8	49 °	212.8 ″	5.02 ^m	11 ^m
	1921		47 °	215 ″
	2006		41 °	217.7 ″
AB-E	2000	one	136 °	193.5 ″	5.02 ^m	17 ^m

Summarizing all the information about the star, we can say that the star Eta Northern Crown A definitely has a satellite Eta Northern Crown B, a 6th magnitude star that rotates around the star Eta Northern Crown A and is gravitationally connected with it. Also, the star, almost certainly has a third companion, This Northern Crown C (which is indicated in the table by AB-E). But about the movement of other satellites, that is, about the companions “C” and “D”, stars of the 13th and 11th magnitude, lying at angular distances of 73.7, 217.7 seconds of arc , we can say that they move too fast for orbital motion, which makes the "satellites" seem to be just stars lying on the line of sight.

Nearest star environment

The following stellar systems are within 20 light-years ^[21] of the star of Eta Northern Crown (only included: the closest star, the brightest (<6.5 ^m ) and noteworthy stars). Their spectral classes are shown against the background of the colors of these classes (these colors are taken from the names of the spectral types and do not correspond to the observed colors of stars):

Star	Spectral class	Distance, st. years
45 Bootes	F5 v	7.91
Ro Northern Crown	G0 III	9.61
Sigma Bootes	F2 v	14.45
Hee Hercules	F9 v	15,99
Sigma of the Northern Crown	F8 III	16.47
14 Hercules	K0 v	17.22
39 Snakes	G1 V	19.22

Near the star, at a distance of 20 light-years , there are about 20 red , orange dwarfs and yellow dwarfs of spectral class G, K and M, as well as 2 white dwarfs that are not on the list.

Notes

Comments

↑ Distance calculated by the given parallax value
↑ ¹ ² ^{3 The} angular diameter (δ) is calculated by the formula:
$\delta =2\arctan \left({\frac {R_{\mathrm {S} }}{d_{\mathrm {S} }}}\right)$ ${\ displaystyle \ delta = 2 \ arctan \ left ({\ frac {R _ {\ mathrm {S}}} {d _ {\ mathrm {S}}} \ right)}$ where R _S is the radius of the star, expressed in a.u. ; d _S is the distance to the star, expressed in a.u.
↑ STF - link to Struve catalog, 1937 - record number in its catalog

Sources

↑ ¹ ² ³ ⁴ ⁵ ⁶ van Leeuwen F. Validation of the new Hipparcos reduction // Astronomy and Astrophysics: journal. - 2007. - Vol. 474 , no. 2 . - P. 653-664 . - DOI : 10.1051 / 0004-6361: 20078357 . - . - arXiv : 0708.1752 .
↑ ¹ ² ³ h Coronae Borealis . Alcyone Bright Star Catalog .
↑ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ¹⁰ ¹¹ ¹² ¹³ ¹⁴ ¹⁵ Pourbaix D. Resolved double-lined spectroscopic binaries: A neglected source of hypothesis-free parallaxes and stellar masses (Eng.) // Astronomy and Astrophysics Supplement Series: journal . - 2000. - Vol. 145 , no. 2 . - P. 215 . - DOI : 10.1051 / aas: 2000237 . - .
↑ ¹ ² ³ ⁴ Leeuwen F. v. Validation of the new Hipparcos reduction // Astron. Astrophys. - EDP Sciences , 2007. - Vol. 474, Iss. 2. - P. 653–664. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361: 20078357 - arXiv: 0708.1752
<a href=" https://wikidata.org/wiki/Track:Q114404 "> </a> <a href=" https://wikidata.org/wiki/Track:Q63615173 "> </a> <a href = " https://wikidata.org/wiki/Track:Q752075 "> </a> <a href=" https://wikidata.org/wiki/Track:Q28315126 "> </a>
↑ ¹ ² ³ ⁴ Lacroute P., Valbousquet A. AGK3 catalog - 1971. - T. 7. - S. 153.
<a href=" https://wikidata.org/wiki/Track:Q292360 "> </a>
↑ ¹ ² Edwards, TW MK classification for visual binary components (Eng.) // The Astronomical Journal: journal. - 1976. - Vol. 81 . - P. 245 . - DOI : 10.1086 / 111879 . - .
↑ ¹ ² ³ ⁴ ⁵ ⁶ Kirkpatrick, J. Davy; Dahn, Conard C .; Monet, David G .; Reid, I. Neill; Gizis, John E.; Liebert, James; Burgasser, Adam J. Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C (Eng.) // The Astronomical Journal: journal. - 2001. - Vol. 121 , no. 6 . - P. 3235 . - DOI : 10.1086 / 321085 . - . - arXiv : astro-ph / 0103218 .
↑ ¹ ² (eng) * eta CrB - Spectroscopic binary , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Eta+Coronae+Borealis > . Retrieved February 6, 2019.
↑ ¹ ² ³ ETA CRB (Eta Coronae Borealis ) . Jim Kaler, Stars .
↑ Soderblom DR Rotational studies of late-type stars. II - Ages of solar-type stars and the rotational history of the sun (Eng.) // The Astrophysical Journal Supplement Series: journal. - 1983. - Vol. 53 . - DOI : 10.1086 / 190880 . - .
↑ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ¹⁰ ¹¹ ¹² (English) * eta CrB A - Star , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id ? Ident =% 403544105 & Name = *% 20eta% 20CrB% 20A & submit = submit > . Retrieved February 6, 2019.
↑ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ¹⁰ ¹¹ ¹² ¹³ ¹⁴ ¹⁵ ¹⁶ Eta Coronae Borealis . Internet Stellar Database . Date of treatment July 7, 2019.
↑ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ (English) * eta CrB B , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%402879168&Name= *% 20eta% 20CrB% 20B & submit = submit > . Retrieved February 6, 2019.
↑ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ (English) * eta CrB C - Brown Dwarf (M <0.08solMass) , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/ sim-id? Ident =% 2A% 20eta% 20CrB% 20C > . Retrieved February 6, 2019.
↑ ¹ ² ³ ⁴ Vizier catalog entry .
↑ M. Asplund , L. Casagrande , S. Cassisi et al. New constraints on the chemical evolution of the solar neighborhood and Galactic disc (s) // Astron. Astrophys. - EDP Sciences , 2011. - Vol. 530. - P. A138. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361 / 201016276
<a href=" https://wikidata.org/wiki/Track:Q114404 "> </a> <a href=" https://wikidata.org/wiki/Track:Q5561486 "> </a> <a href = " https://wikidata.org/wiki/Track:Q55879289 "> </a> <a href=" https://wikidata.org/wiki/Track:Q61822461 "> </a> <a href = " https://wikidata.org/wiki/Track:Q56476274 "> </a> <a href=" https://wikidata.org/wiki/Track:Q752075 "> </a> <a href = " https : //wikidata.org/wiki/Track: Q58264488 "> </a>
↑ ¹ ² ³ HR 5727 (Russian) . A catalog of bright stars .
↑ ¹ ² Eta Coronae Borealis (2 Coronae Borealis A) Star Facts . Universe Guide .
↑ NSV 7054 . GAISH .
↑ Kirkpatrick, J. Davy; Dahn, Conard C .; Monet, David G .; Reid, I. Neill; Gizis, John E .; Liebert, James; Burgasser, Adam J. Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C (Eng.) // The Astronomical Journal : journal. - 2001. - Vol. 121 .
↑ Stars within 20 light-years of Eta Coronae Borealis: (English) . Internet Stellar Database . Date of treatment July 7, 2019.

Links

Eta Northern Crown Image

15 ^h 23 ^m 12.3 ^s , + 30 ° 17 ′ 16.17 ″

[2] Distance calculated by the given parallax value

[a-20] ¹ ² ^{3 The} angular diameter (δ) is calculated by the formula:
$\delta =2\arctan \left({\frac {R_{\mathrm {S} }}{d_{\mathrm {S} }}}\right)$ ${\ displaystyle \ delta = 2 \ arctan \ left ({\ frac {R _ {\ mathrm {S}}} {d _ {\ mathrm {S}}} \ right)}$ where R _S is the radius of the star, expressed in a.u. ; d _S is the distance to the star, expressed in a.u.

[23] STF - link to Struve catalog, 1937 - record number in its catalog

[van_Leeuwen2007-1] ¹ ² ³ ⁴ ⁵ ⁶ van Leeuwen F. Validation of the new Hipparcos reduction // Astronomy and Astrophysics: journal. - 2007. - Vol. 474 , no. 2 . - P. 653-664 . - DOI : 10.1051 / 0004-6361: 20078357 . - . - arXiv : 0708.1752 .

[Alcyone-3] ¹ ² ³ h Coronae Borealis . Alcyone Bright Star Catalog .

[Pourbaix2000-4] ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ¹⁰ ¹¹ ¹² ¹³ ¹⁴ ¹⁵ Pourbaix D. Resolved double-lined spectroscopic binaries: A neglected source of hypothesis-free parallaxes and stellar masses (Eng.) // Astronomy and Astrophysics Supplement Series: journal . - 2000. - Vol. 145 , no. 2 . - P. 215 . - DOI : 10.1051 / aas: 2000237 . - .

[_033d9932e55251ec-5] ¹ ² ³ ⁴ Leeuwen F. v. Validation of the new Hipparcos reduction // Astron. Astrophys. - EDP Sciences , 2007. - Vol. 474, Iss. 2. - P. 653–664. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361: 20078357 - arXiv: 0708.1752
<a href=" https://wikidata.org/wiki/Track:Q114404 "> </a> <a href=" https://wikidata.org/wiki/Track:Q63615173 "> </a> <a href = " https://wikidata.org/wiki/Track:Q752075 "> </a> <a href=" https://wikidata.org/wiki/Track:Q28315126 "> </a>

[_8c820a9d9d77d1a8-6] ¹ ² ³ ⁴ Lacroute P., Valbousquet A. AGK3 catalog - 1971. - T. 7. - S. 153.
<a href=" https://wikidata.org/wiki/Track:Q292360 "> </a>

[MKclass-7] ¹ ² Edwards, TW MK classification for visual binary components (Eng.) // The Astronomical Journal: journal. - 1976. - Vol. 81 . - P. 245 . - DOI : 10.1086 / 111879 . - .

[brown-8] ¹ ² ³ ⁴ ⁵ ⁶ Kirkpatrick, J. Davy; Dahn, Conard C .; Monet, David G .; Reid, I. Neill; Gizis, John E.; Liebert, James; Burgasser, Adam J. Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C (Eng.) // The Astronomical Journal: journal. - 2001. - Vol. 121 , no. 6 . - P. 3235 . - DOI : 10.1086 / 321085 . - . - arXiv : astro-ph / 0103218 .

[SIMBAD-9] ¹ ² (eng) * eta CrB - Spectroscopic binary , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Eta+Coronae+Borealis > . Retrieved February 6, 2019.

[kaler-10] ¹ ² ³ ETA CRB (Eta Coronae Borealis ) . Jim Kaler, Stars .

[Soderblom1983-11] Soderblom DR Rotational studies of late-type stars. II - Ages of solar-type stars and the rotational history of the sun (Eng.) // The Astrophysical Journal Supplement Series: journal. - 1983. - Vol. 53 . - DOI : 10.1086 / 190880 . - .

[SIMBADA-12] ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ¹⁰ ¹¹ ¹² (English) * eta CrB A - Star , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id ? Ident =% 403544105 & Name = *% 20eta% 20CrB% 20A & submit = submit > . Retrieved February 6, 2019.

[stellardatabase-13] ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ¹⁰ ¹¹ ¹² ¹³ ¹⁴ ¹⁵ ¹⁶ Eta Coronae Borealis . Internet Stellar Database . Date of treatment July 7, 2019.

[SIMBADB-14] ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ (English) * eta CrB B , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%402879168&Name= *% 20eta% 20CrB% 20B & submit = submit > . Retrieved February 6, 2019.

[SIMBADC-15] ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ (English) * eta CrB C - Brown Dwarf (M <0.08solMass) , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/ sim-id? Ident =% 2A% 20eta% 20CrB% 20C > . Retrieved February 6, 2019.

[WDS-16] ¹ ² ³ ⁴ Vizier catalog entry .

[_46a2ca07124a151d-17] M. Asplund , L. Casagrande , S. Cassisi et al. New constraints on the chemical evolution of the solar neighborhood and Galactic disc (s) // Astron. Astrophys. - EDP Sciences , 2011. - Vol. 530. - P. A138. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361 / 201016276
<a href=" https://wikidata.org/wiki/Track:Q114404 "> </a> <a href=" https://wikidata.org/wiki/Track:Q5561486 "> </a> <a href = " https://wikidata.org/wiki/Track:Q55879289 "> </a> <a href=" https://wikidata.org/wiki/Track:Q61822461 "> </a> <a href = " https://wikidata.org/wiki/Track:Q56476274 "> </a> <a href=" https://wikidata.org/wiki/Track:Q752075 "> </a> <a href = " https : //wikidata.org/wiki/Track: Q58264488 "> </a>

[astromyth-18] ¹ ² ³ HR 5727 (Russian) . A catalog of bright stars .

[UniverseGuide-19] ¹ ² Eta Coronae Borealis (2 Coronae Borealis A) Star Facts . Universe Guide .

[gcvs-21] NSV 7054 . GAISH .

[Kirkpatrick-22] Kirkpatrick, J. Davy; Dahn, Conard C .; Monet, David G .; Reid, I. Neill; Gizis, John E .; Liebert, James; Burgasser, Adam J. Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C (Eng.) // The Astronomical Journal : journal. - 2001. - Vol. 121 .

[stellardatabase20ly-24] Stars within 20 light-years of Eta Coronae Borealis: (English) . Internet Stellar Database . Date of treatment July 7, 2019.