55 Cancri

55 Cancri is a binary star system located 41[1] light-years away from the Sun in the zodiac constellation of Cancer. It has the Bayer designation Rho1 Cancri (ρ1 Cancri); 55 Cancri is the Flamsteed designation (abbreviated 55 Cnc). The system consists of a K-type star (designated 55 Cancri A, also named Copernicus /koʊˈpɜːrnɪkəs/)[14] and a smaller red dwarf (55 Cancri B).

For other stars with this Bayer designation, see ρ Cancri.

55 Cancri
Location of 55 Cancri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cancer
Pronunciation /ˈkæŋkraɪ/ or /ˈkæŋkriː/
55 Cancri A
Right ascension  08h 52m 35.8113s[1]
Declination +28° 19′ 50.957″[1]
Apparent magnitude (V) 5.95[2]
55 Cancri B
Right ascension  08h 52m 40.8627s[3]
Declination +28° 19′ 58.825″[3]
Apparent magnitude (V) 13.15[4]
Characteristics
55 Cancri A
Spectral type K0IV-V[5]
U−B color index 0.63[6]
B−V color index 0.87[6]
55 Cancri B
Spectral type M3.5-4V[7]
B−V color index 1.7[4]
Astrometry
55 Cancri A
Radial velocity (Rv)27.51[1] km/s
Proper motion (μ) RA: −485.872±0.134[1] mas/yr
Dec.: −233.651±0.109[1] mas/yr
Parallax (π)79.4274 ± 0.077[1] mas
Distance41.06 ± 0.04 ly
(12.59 ± 0.01 pc)
Absolute magnitude (MV)+5.50[8]
55 Cancri B
Proper motion (μ) RA: −481.204±0.151[3] mas/yr
Dec.: −244.779±0.106[3] mas/yr
Parallax (π)80.1166 ± 0.1090[3] mas
Distance40.71 ± 0.06 ly
(12.48 ± 0.02 pc)
Absolute magnitude (MV)12.58[9]
Details
55 Cnc A
Mass0.960±0.067[10] M☉
Radius0.960±0.018[10] R☉
Luminosity0.589±0.014[10] L☉
Surface gravity (log g)4.37[5] cgs
Temperature5,165±46[10] K
Metallicity [Fe/H]−0.09[5] dex
Rotation42.2 d
Age7.4–8.7[11] Gyr
55 Cnc B
Mass0.255[12] M☉
Radius0.273[12] R☉
Luminosity0.003[13] L☉
Temperature3,233[9] K
Rotational velocity (v sin i)6.110[9] km/s
Other designations
Copernicus, Rho1 Cancri, 55 Cnc, BD+28°1660, GJ 324, HD 75732, HIP 43587, HR 3522, SAO 80585
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

As of 2015, five extrasolar planets (designated 55 Cancri b, c, d, e and f; named Galileo, Brahe, Lipperhey, Janssen and Harriot, respectively) are believed to orbit 55 Cancri A.

Nomenclature

55 Cancri is the system's Flamsteed designation. It also bears the Bayer designation ρ¹ Cancri (Latinised to Rho¹ Cancri) and the Bright Star Catalogue designation HR 3522. The two components are designated A and B,[15] though A is itself sometimes referred to as 55 Cancri.[16] The first planet discovered orbiting 55 Cancri A was designated HR 3522b by its discoverers,[17] though it is more commonly referred to as 55 Cancri b.[18] Under the rules for naming objects in binary star systems it should be named 55 Cancri Ab[19] and this more formal form is occasionally used to avoid confusion with the secondary star 55 Cancri B. The other planets discovered were designated 55 Cancri c, d, e and f, in order of their discovery.

In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars.[20] The process involved public nomination and voting for the new names.[21] In December 2015, the IAU announced the winning names were Copernicus for 55 Cancri A and Galileo, Brahe, Lipperhey, Janssen and Harriot for its planets (b, c, d, e and f, respectively).[22]

The winning names were those submitted by the Royal Netherlands Association for Meteorology and Astronomy of the Netherlands. They honor the astronomers Nicolaus Copernicus, Galileo Galilei, Tycho Brahe and Thomas Harriot and the spectacle makers and telescope pioneers Hans Lipperhey and Jacharias Janssen.[23] (The IAU originally announced the winning name was Lippershey for 55 Cancri d. In January 2016, in recognition that his actual name was Lipperhey (with Lippershey an error introduced in the 19th century), the exoplanet name was corrected to Lipperhey by the IAU and that name was submitted to the official sites that keep track of astronomical information.[22][23])

In 2016, the IAU organized a Working Group on Star Names (WGSN)[24] to catalog and standardize proper names for stars. In its first bulletin of July 2016,[25] the WGSN explicitly recognized the names of exoplanets and their host stars approved by the Executive Committee Working Group Public Naming of Planets and Planetary Satellites, including the names of stars adopted during the 2015 NameExoWorlds campaign. This star is now so entered in the IAU Catalog of Star Names.[14]

Stellar system

The 55 Cancri system is located fairly close to the Solar System: the Gaia astrometry satellite measured the parallax of 55 Cancri A as 79.4274 milliarcseconds, corresponding to a distance of 12.59 parsecs (41.06 light years).[1] 55 Cancri A has an apparent magnitude of 5.95, making it just visible to the naked eye under very dark skies. The red dwarf 55 Cancri B is of the 13th magnitude and only visible through a telescope. The two components are separated by an estimated distance of 1065 AU[26] (one thousand times the distance from the Earth to the Sun). Despite their wide separation, the two stars appear to be gravitationally bound, as they share a common proper motion.[16]

The primary star, 55 Cancri A, has a spectral type of K0IV-V, indicating a main sequence or subgiant star. It is smaller in radius and slightly less massive than the Sun, and so is cooler and less luminous. The star has only low emission from its chromosphere, and is not variable in the visible spectrum;[16] but it is variable in X-rays.[27] It is more enriched than the Sun in elements heavier than helium, with 186% the solar abundance of iron; it is therefore classified as a rare "super metal-rich" (SMR) star.[16] This abundance of metal makes estimating the star's age and mass difficult, as evolutionary models are less well defined for such stars. 55 Cancri A also has more carbon than the Sun, with a C/O ratio of 0.78,[28] compared to solar value of 0.55. Age estimates for 55 Cancri A include 7.4–8.7 billion years[11] and 10.2 ± 2.5 billion years.[29]

A hypothesis for the high metal content in SMR dwarf stars is that material enriched in heavy elements fell into the atmosphere from a protoplanetary disk. This would pollute the star's external layers, resulting in a higher than normal metallicity. The lack of a deep convection zone would mean that the outer layers would retain higher abundance ratios of these heavy elements.[30]

Observations of 55 Cancri A in the submillimeter region of the spectrum have thus far failed to detect any associated dust. The upper limit on emissions within 100 AU of this star is about 850 mJy, at a wavelength of 850 μm. This limits the total mass of fine dust around the star to less than 0.01% of the Earth's mass. However, this does not exclude the presence of an asteroid belt or a Kuiper belt equivalent.[31]

The secondary, 55 Cancri B, is a red dwarf star much less massive and luminous than the Sun. There are indications that component B may itself be a double star, though this is uncertain.[15]

Planetary system
Comparison of the orbits of the inner planets of 55 Cancri A (black) with the planets of the Solar System.

The 55 Cancri system was the first known to have four, and later five planets, and may possibly have more. The innermost planet, e, transits 55 Cancri A as viewed from Earth.[32] The next planet, b, is non-transiting but there is tentative evidence that it is surrounded by an extended atmosphere that does transit the star.[27]

In 1997, the discovery of a 51 Pegasi-like planet orbiting 55 Cancri A was announced, together with the planet of Tau Boötis and the inner planet of Upsilon Andromedae.[17] The planet was discovered by measuring the star's radial velocity, which showed a periodicity of around 14.7 days corresponding to a planet at least 78% of the mass of Jupiter. These radial velocity measurements still showed a drift unaccounted-for by this planet, which could be explained by the gravitational influence of a more distant object.

In 1998 the discovery of a possible dust disk around 55 Cancri A was announced.[33] Calculations gave the disk radius at least 40 AU, similar to the Kuiper belt in the Solar System, with an inclination of 25° with respect to the plane of the sky. However, the discovery could not be verified and was later deemed to be spurious, caused instead by background galaxies.[34]

The Solar System compared with the planetary system of 55 Cancri. (Note: this depiction was made before planets e and f were discovered.)

After making further radial velocity measurements, a planet orbiting at a distance of around 5 AU was announced in 2002.[16] This planet received the designation 55 Cancri d. At the time of discovery, the planet was thought to be in an orbit of mild eccentricity (close to 0.1), but this value was increased by later measurements. Even after accounting for these two planets, a periodicity at 43 days remained, possibly due to a third planet. Measurements of the star suggested that this was close to the star's rotation period, which raised the possibility that the 43-day signal was caused by stellar activity. This possible planet received the designation 55 Cancri c.

Artist's Rendition of 55 Cnc's planets

55 Cancri e was announced in 2004.[35] With 8.3 Earth masses, it is a large super-Earth which was originally thought to have an orbital period of 2.8 days, though it was later found that this was an alias of its true period of 0.74 days by observations of e transiting in 2011.[32] This planet was the first known instance of a fourth extrasolar planet in one system, and was the shortest-period planet until the discovery of PSR J1719-1438 b. The measurements that led to the discovery of this planet also confirmed the existence of 55 Cancri c.

In 2005, Jack Wisdom combined three data sets and drew two distinct conclusions: that the 2.8 day planet was an alias and that there was a Neptune-scale planet with a period near 261 days. Fischer et al. (2008)[36] reported new observations that they said confirmed the existence of the 2.8 day planet, as first reported by McArthur et al. (2004), and a 260-day Neptune-sized planet, as first reported by Wisdom (2005).[37] However, Dawson and Fabrycky (2010)[38] concluded that the 2.8 day planet was indeed an alias, as suggested by Wisdom (2005), and that the correct period was 0.7365 days.

In 2007, Fisher et al. confirmed the existence of the 260 day planet proposed in 2005 by Wisdom. This planet, 55 Cancer f, was the first occurrence of a fifth extrasolar planet in one system. With a similar mass to c, it has a 260-day orbit, towards the inner edge of 55 Cancri A's habitable zone.[39][40] The planet itself is not thought to be conducive to life, but hypothetical moons in principle could maintain at least microbial life.

The planet e's eccentricity is poorly defined; varying values between 0 and 0.4 does not significantly improve the fit, so an eccentricity of 0.2 was assumed. Taking interactions between the planets into account results in a near-zero orbital eccentricity.

Astrometric observations with the Hubble Space Telescope measured an inclination of 53° of the outer planet d,[35] though this result relies on the precise orbital parameters which have been substantially revised since this was published.[41] The observed transits of e suggest an orbit normal inclined within 9° to the line-of-sight, and a possible detection of the transit of an extended atmosphere around 55 Cancri b would, if confirmed, imply that it too is in an orbit that is close to edge-on.[27] Between them, no measurement of c's nor f's inclination has been made. It had been thought that with five planets, the system cannot deviate far from coplanar in order to maintain stability.[40] An attempt to measure the spin-orbit misalignment of the innermost planet reported that it was in a nearly polar orbit,[42] but this interpretation of the data has since been challenged by a subsequent study, with noted inconsistencies between the implied and measured stellar rotation.[43]

The approximate ratios of periods of adjacent orbits are (proceeding outward): 1:20, 1:3, 1:6, 1:20. The nearly 1:3 ratio between 55 Cancri b and c is apparently a near resonance, rather than a genuine mean motion resonance.[40]

More planets are possible within the stable zone, between f and d at 0.9 to 3.8 AU with eccentricities below 0.4. Given hypothetical planet g of up to 50 Earth masses, stable mean motion resonance regions lie at 3f:2g, 2g:1d, and 3g:2d. As for the space outside d's orbit, its stability zone begins beyond 10 AU, though there is a stability zone between 8.6 – 9 AU due to a 2:1 resonance.[44]

The 55 Cancri A planetary system[32][45][46]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
e (Janssen) 7.99 +0.32
−0.33 M⊕		 0.01544 ± 0.00011 0.7365474 ± 0.000013 0.05 ± 0.03 83.59 +0.47
−0.44°		 1.875 ± 0.029 R⊕
b (Galileo) 0.825 ± 0.003 MJ 0.1148 ± 0.0008 14.6507 ± 0.0004 0.010 ± 0.003 ~85° —
c (Brahe) ≥0.171 ± 0.004 MJ 0.2403 ± 0.0017 44.364 ± 0.007 0.005 ± 0.003 — —
f (Harriot) ≥0.155 ± 0.008 MJ 0.781 ± 0.006 259.8 ± 0.5 0.30 ± 0.05 — —
d (Lipperhey) ≥3.82 ± 0.04 MJ 5.74 ± 0.04 5169 ± 53 0.014 ± 0.009 — —

Communication

A METI message was sent to 55 Cancri. It was transmitted from Eurasia's largest radar – 70-meter (230-foot) Eupatoria Planetary Radar. The message was named Cosmic Call 2; it was sent on July 6, 2003, and it will arrive at 55 Cancri in May 2044.[47]

See also

References
  1. 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.
  2. Van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085.
  3. 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.
  4. Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". VizieR On-line Data Catalog. Bibcode:2012yCat.1322....0Z.
  5. 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.
  6. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  7. Alonso-Floriano, F. J.; Morales, J. C.; Caballero, J. A.; Montes, D.; Klutsch, A.; Mundt, R.; Cortés-Contreras, M.; Ribas, I.; Reiners, A.; Amado, P. J.; Quirrenbach, A.; Jeffers, S. V. (2015). "CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS". Astronomy and Astrophysics. 577: A128. arXiv:1502.07580. Bibcode:2015A&A...577A.128A. doi:10.1051/0004-6361/201525803.
  8. 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.
  9. Houdebine, E. R.; Mullan, D. J.; Paletou, F.; Gebran, M. (2016). "Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin I and P/Sin I for a Large Sample of Late-K and M Dwarfs". The Astrophysical Journal. 822 (2): 97. arXiv:1604.07920. Bibcode:2016ApJ...822...97H. doi:10.3847/0004-637X/822/2/97.
  10. Ligi, R.; et al. (February 2016), "Radii, masses, and ages of 18 bright stars using interferometry and new estimations of exoplanetary parameters", Astronomy & Astrophysics, 586: 23, arXiv:1511.03197, Bibcode:2016A&A...586A..94L, doi:10.1051/0004-6361/201527054, A94.
  11. Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
  12. Newton, Elisabeth R.; Irwin, Jonathan; Charbonneau, David; Berlind, Perry; Calkins, Michael L.; Mink, Jessica (2017). "The Hα Emission of Nearby M Dwarfs and its Relation to Stellar Rotation". The Astrophysical Journal. 834 (1): 85. arXiv:1611.03509. Bibcode:2017ApJ...834...85N. doi:10.3847/1538-4357/834/1/85.
  13. Gaidos, E.; Mann, A. W.; Lépine, S.; Buccino, A.; James, D.; Ansdell, M.; Petrucci, R.; Mauas, P.; Hilton, E. J. (2014). "Trumpeting M dwarfs with CONCH-SHELL: A catalogue of nearby cool host-stars for habitable exoplanets and life". Monthly Notices of the Royal Astronomical Society. 443 (3): 2561. arXiv:1406.7353. Bibcode:2014MNRAS.443.2561G. doi:10.1093/mnras/stu1313.
  14. "IAU Catalog of Star Names". Retrieved 28 July 2016.
  15. Raghavan, Deepak; et al. (2006). "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems". The Astrophysical Journal. 646 (1): 523–542. arXiv:astro-ph/0603836. Bibcode:2006ApJ...646..523R. doi:10.1086/504823.
  16. Marcy, Geoffrey W.; et al. (2002). "A planet at 5 AU Around 55 Cancri". The Astrophysical Journal. 581 (2): 1375–1388. arXiv:astro-ph/0207294. Bibcode:2002ApJ...581.1375M. doi:10.1086/344298.
  17. Butler, R. Paul; et al. (1997). "Three New 51 Pegasi Type Planets". The Astrophysical Journal Letters. 474 (2): L115–L118. Bibcode:1997ApJ...474L.115B. doi:10.1086/310444.
  18. Jean Schneider (2011). "Notes for Planet 55 Cnc b". Extrasolar Planets Encyclopaedia. Retrieved 8 October 2011.
  19. William I. Hartkopf & Brian D. Mason. "Addressing confusion in double star nomenclature: The Washington Multiplicity Catalog". United States Naval Observatory. Archived from the original on 2011-05-17. Retrieved 2011-10-08.
  20. NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
  21. NameExoWorlds The Process
  22. Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
  23. NameExoWorlds The Approved Names
  24. "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  25. "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  26. Eggenberger, A.; et al. (2003). "Planets in Binaries". Scientific Frontiers in Research on Extrasolar Planets. 294: 43–46. Bibcode:2003ASPC..294...43E.
  27. D. Ehrenreich; et al. (October 2, 2012). "Hint of a transiting extended atmosphere on 55 Cancri b". Astronomy & Astrophysics. 547: A18. arXiv:1210.0531. Bibcode:2012A&A...547A..18E. doi:10.1051/0004-6361/201219981.
  28. Teske, Johanna K.; Cunha, Katia; Schuler, Simon C.; Griffith, Caitlin A.; Smith, Verne V. (2013). "Carbon and Oxygen Abundances in Cool Metal-rich Exoplanet Hosts: A Case Study of the C/O Ratio of 55 Cancri". The Astrophysical Journal. 778 (2): 132. arXiv:1309.6032. Bibcode:2013ApJ...778..132T. doi:10.1088/0004-637X/778/2/132.
  29. von Braun, Kaspar; Tabetha, S. Boyajian; ten Brummelaar, Theo; Kane, Stephen R.; van Belle, Gerard T.; Ciardi, David R.; Raymond, Sean N.; López-Morales, Mercedes; McAlister, Harold A.; Schaefer, Gail (2011). "55 Cancri: Stellar Astrophysical Parameters, a Planet in the Habitable Zone, and Implications for the Radius of a Transiting Super-Earth". The Astrophysical Journal. 740 (1): 49–54. arXiv:1106.1152. Bibcode:2011ApJ...740...49V. doi:10.1088/0004-637X/740/1/49.
  30. Pasquini, Luca; Hatzes, Artie (2007-07-06). "Star Surface Polluted by Planetary Debris". ESO. Archived from the original on 30 September 2007. Retrieved 2007-11-08.
  31. Jayawardhana, Ray; et al. (2002). "New Submillimeter Limits on Dust in the 55 Cancri Planetary System". The Astrophysical Journal Letters. 570 (2): L93–L96. arXiv:astro-ph/0204140. Bibcode:2002ApJ...570L..93J. doi:10.1086/341101.
  32. Winn, Joshua N.; et al. (2011). "A Super-Earth Transiting a Naked-Eye Star". The Astrophysical Journal Letters. 737 (1). article number L18. arXiv:1104.5230. Bibcode:2011ApJ...737L..18W. doi:10.1088/2041-8205/737/1/L18.
  33. Trilling, David E.; Brown, Robert H. (1998). "A circumstellar dust disk around a star with a known planetary companion" (PDF). Nature. 395 (6704): 775–777. Bibcode:1998Natur.395..775T. doi:10.1038/27389.
  34. Schneider, G.; et al. (2001). "NICMOS Coronagraphic Observations of 55 Cancri". The Astronomical Journal. 121 (1): 525–537. arXiv:astro-ph/0010175. Bibcode:2001AJ....121..525S. doi:10.1086/318050.
  35. McArthur, Barbara E.; et al. (2004). "Detection of a NEPTUNE-mass planet in the ρ1 Cnc system using the Hobby-Eberly Telescope". The Astrophysical Journal Letters. 614 (1): L81–L84. arXiv:astro-ph/0408585. Bibcode:2004ApJ...614L..81M. doi:10.1086/425561.
  36. Fischer, Debra A.; Marcy, Geoffrey W.; Butler, R. Paul; Vogt, Steven S.; Laughlin, Greg; Henry, Gregory W.; Abouav, David; Peek, Kathryn M. G.; Wright, Jason T.; Johnson, John A.; McCarthy, Chris; Isaacson, Howard (2008). "Five Planets Orbiting 55 Cancri". The Astrophysical Journal. 675: 790–801. arXiv:0712.3917. Bibcode:2008ApJ...675..790F. doi:10.1086/525512.
  37. "A Neptune-sized Planet in the ρ 1 Cancri System" (PDF).
  38. Dawson, Rebekah I.; Fabrycky, Daniel C. (2010). "RADIAL VELOCITY PLANETS DE-ALIASED: A NEW, SHORT PERIOD FOR SUPER-EARTH 55 Cnc e". The Astrophysical Journal. 722: 937–953. arXiv:1005.4050. Bibcode:2010ApJ...722..937D. doi:10.1088/0004-637X/722/1/937.
  39. "Astronomers Discover Record Fifth Planet Around Nearby Star 55 Cancri". Sciencedaily.com. November 6, 2007. Archived from the original on 26 September 2008. Retrieved 2008-09-14.
  40. Fischer, Debra A.; et al. (2008). "Five Planets Orbiting 55 Cancri". The Astrophysical Journal. 675 (1): 790–801. arXiv:0712.3917. Bibcode:2008ApJ...675..790F. doi:10.1086/525512.
  41. Nelson, Benjamin E.; et al. (2014). "The 55 Cancri planetary system: fully self-consistent N-body constraints and a dynamical analysis". Monthly Notices of the Royal Astronomical Society. 441 (1): 442–451. arXiv:1402.6343. Bibcode:2014MNRAS.441..442N. doi:10.1093/mnras/stu450.
  42. Vincent Bourrier; Guillaume Hébrard (2014). "Detecting the spin-orbit misalignment of the super-Earth 55 Cnc e". Astronomy & Astrophysics. 569: A65. arXiv:1406.6813. Bibcode:2014A&A...569A..65B. doi:10.1051/0004-6361/201424266.
  43. Mercedes Lopez-Morales; Amaury H. M. J. Triaud; Florian Rodler; Xavier Dumusque; Lars A. Buchhave; A. Harutyunyan; Sergio Hoyer; Roi Alonso; Michael Gillon; Nathan A. Kaib; David W. Latham; Christophe Lovis; Francesco Pepe; Didier Queloz; Sean N.Raymond; Damien Segransan; Ingo P. Waldmann; Stephane Udry (2014). "Rossiter-McLaughlin Observations of 55 Cnc e". The Astrophysical Journal. 792 (2): L31. arXiv:1408.2007. Bibcode:2014ApJ...792L..31L. doi:10.1088/2041-8205/792/2/L31.
  44. Raymond, Sean N.; et al. (2008). "A dynamical perspective on additional planets in 55 Cancri". The Astrophysical Journal. 689 (1): 478–491. arXiv:0808.3295. Bibcode:2008ApJ...689..478R. doi:10.1086/592772.
  45. Dawson, Rebekah I.; Fabrycky, Daniel C. (2010). "Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e". The Astrophysical Journal. 722 (1): 937–953. arXiv:1005.4050. Bibcode:2010ApJ...722..937D. doi:10.1088/0004-637X/722/1/937.
  46. Bourrier, V.; Dumusque, X.; Dorn, C.; Henry, G. W.; Astudillo-Defru, N.; Rey, J.; Benneke, B.; Hébrard, G.; Lovis, C.; Demory, B. O.; Moutou, C.; Ehrenreich, D. (2018). "The 55 Cancri system reassessed". Astronomy & Astrophysics. 619: A1. arXiv:1807.04301. doi:10.1051/0004-6361/201833154.
  47. "Передача и поиски разумных сигналов во Вселенной". Cplire.ru. Retrieved 2008-09-14.

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