Epsilon Coronae Borealis

This article will address the topic of Epsilon Coronae Borealis, which has generated great interest in different areas in recent years. Since its emergence, Epsilon Coronae Borealis has captured the attention of experts and the general public due to its relevance and impact in today's society. Throughout this writing, different aspects related to Epsilon Coronae Borealis will be explored, such as its origin, evolution, influence and possible future implications. Likewise, different perspectives and approaches will be analyzed that will allow us to better understand the importance of Epsilon Coronae Borealis in the current context.

ε Coronae Borealis
Location of ε Coronae Borealis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Corona Borealis
Right ascension 15h 57m 35.25147s[1]
Declination +26° 52′ 40.3635″[1]
Apparent magnitude (V) 4.13[2]
Characteristics
Spectral type K2 III[2]
U−B color index +1.28[3]
B−V color index +1.235[3]
Astrometry
Radial velocity (Rv)–32.42[2] km/s
Proper motion (μ) RA: –77.07[1] mas/yr
Dec.: –60.61[1] mas/yr
Parallax (π)13.4922±0.1023 mas[4]
Distance242 ± 2 ly
(74.1 ± 0.6 pc)
Absolute magnitude (MV)−0.02[5]
Details[6]
Mass1.37±0.24 M☉
Radius21.87+0.98
−0.99 R☉
Luminosity (bolometric)162.9±9.4 L☉
Surface gravity (log g)1.94±0.15[7] cgs
Temperature4,408±109 K
Metallicity −0.22±0.03[7] dex
Rotational velocity (v sin i)2.4[8] km/s
Age3.24±1.81 Gyr
Other designations
13 Coronae Borealis, BD+27°2558, HD 143107, HIP 78159, HR 5947, SAO 84098, 2MASS J15573523+2652400[9]
Database references
SIMBADdata

Epsilon Coronae Borealis, Latinized from ε Coronae Borealis, is a multiple star system in the constellation Corona Borealis located around 230 light-years from the Solar System. It shines with a combined apparent magnitude of 4.13,[9] meaning it is visible to the unaided eye in all night skies except those brightly lit in inner city locations.[10]

This star has a stellar spectrum matching the class K2III, which indicate it is a giant star that exhausted its hydrogen supply at its core and evolved.[11] Being 40% more massive than the Sun and 3.2 billion years old, it expanded to over 20 times the Sun's size and cooled to an effective temperature of 4,408 K.[6] That is, Epsilon Coronae Borealis's diameter is about one-quarter of Mercury's orbit.[12] The star radiates with 160 times the Sun's luminosity.[6]

Epsilon Coronae Borealis B is a companion star thought to be an orange dwarf of spectral types K3V to K9V that orbits at a distance of 135 astronomical units, completing one orbit every 900 years.[12]

A faint (magnitude 11.5) star, 1.5 arc minutes away, has been called Epsilon Coronae Borealis C although it is only close by line of sight and is unrelated to the system.[12][13]

Epsilon Coronae Borealis lies one degree north of (and is used as a guide for) the variable T Coronae Borealis.[12]

Planetary system

The ε CrB star system's radial velocity was observed over seven years from January 2005 to January 2012, during which time a 'wobble' with a period of around 418 days was recorded. This has been calculated to be a planet around 6.7 times as massive as Jupiter orbiting at a distance of 1.3 astronomical units with an eccentricity of 0.11.[11]

The Epsilon Coronae Borealis planetary system[14]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥6.7 ± 0.3 MJ 1.3 417.9 ± 0.5 0.11 ± 0.03 — —

References

  1. ^ a b c d van Leeuwen, F. (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.
  2. ^ a b c Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  3. ^ a b Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M.
  4. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  6. ^ a b c Baines, Ellyn K.; et al. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1), 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b, S2CID 119427037.
  7. ^ a b Mortier, A.; et al. (September 2013), "New and updated stellar parameters for 71 evolved planet hosts. On the metallicity-giant planet connection", Astronomy & Astrophysics, 557: 19, arXiv:1307.7870, Bibcode:2013A&A...557A..70M, doi:10.1051/0004-6361/201321641, S2CID 55027519, A70.
  8. ^ Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  9. ^ a b "eps CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-17.{{cite web}}: CS1 maint: postscript (link)
  10. ^ Bortle, John E. (February 2001). "The Bortle Dark-Sky Scale". Sky & Telescope. Sky Publishing Corporation. Archived from the original on 2014-03-31. Retrieved 2013-02-20.
  11. ^ a b Lee, B.-C.; Han, I.; Park, M.-G.; Mkrtichian, D. E.; Kim, K.-M. (2012). "A planetary companion around the K giant ɛ Corona Borealis". Astronomy & Astrophysics. 546: 5. arXiv:1209.1187. Bibcode:2012A&A...546A...5L. doi:10.1051/0004-6361/201219347. S2CID 55260442. A5.
  12. ^ a b c d Kaler, James B. (19 August 2011). "Epsilon and T Coronae Borealis". Stars. University of Illinois. Retrieved 16 November 2014.
  13. ^ SIMBAD, CCDM J15576+2652C -- Star in double system (accessed 16 November 2014)
  14. ^ Jean Schneider (2003). "Planet eps CrB b". Extrasolar Planets Encyclopaedia. Retrieved 4 February 2017.