Copernicus (star)

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Double star
Copernicus
Copernicus A and the planet Janssen (artist's impression).
Copernicus A and the planet Janssen (artist's impression).
Observation
dates equinox :  J2000.0 , epoch : J2000.0
AladinLite
Constellation cancer
Known exoplanets

5

Astrometry
distance  40.9 ly
(12.5 pc )
Individual data
Names A ; B.
Observation data:
Right ascension A. 8523608 h 52 m 36 s
B. 8524108 h 52 m 41 s
declination A. 2281951+ 28 ° 19 ′ 51 ″
B. 2281959+ 28 ° 19 ′ 59 ″
Apparent brightness A. 5.95 likes
B. 13.15 likes
Typing:
Spectral class A. G8 V
B. M3.5-4V
Physical Properties:
Absolute vis.
Brightness M vis 		A. 5.46 likes
B. 12.66 mag
Dimensions A. 0.95 ± 0.10 M ☉
B. 0.13 M ☉
radius A. 0.96 R ☉
B. 0.30 R ☉
Luminosity A. 0.63 L ☉
B. 0.0076 L ☉
Age 4.5 billion years
Other names
and catalog entries
Bayer name ρ 1  Cancri
Flamsteed name 55 Cancri
Bonn survey BD + 28 ° 1660
Bright Star Catalog HR 3522 [1]
Henry Draper Catalog HD 75732 [2]
SAO catalog SAO 80478 [3]
Tycho catalog TYC 1949-2012-1 [4]
Hipparcos catalog HIP 43587 [5]
Further designations: FY 324
  LHS 2062 LHS 2063

Template: Infobox double star / maintenance / single coordinates

Copernicus ( Bayer designation Rho 1  Cancri , Flamsteed designation 55 Cancri , in short: 55 CNC ) is a binary star system that is about 41 light-years from the sun away. It is located in the constellation Cancer with a right ascension of 08h 52m 35.8s and a declination of + 28 ° 19 ′ 50.9 ″ ( equinox 2000.0). The system consists of the Yellow Dwarf Copernicus A and the red dwarf Copernicus B . With five known exoplanets , Copernicus is currently one of the largest known planetary systems outside the solar system .

Physical Properties

Copernicus A

Copernicus A (55 Cnc A) with a radius of 0.96 solar radii is both slightly smaller and less luminous than the sun . Both stars belong to the spectral class  G, but Copernicus A has a slightly later subtype with G8 than the sun with G2. This slight difference is due to the slightly cooler surface temperature of around 5300 ° C (5570 ± 50K) compared to the sun. The star shows little or no variability and little radiation from its chromosphere . Like the sun, it belongs to the main sequence stars of luminosity class V. Consequently, they are in the stable phase of hydrogen burning . The deviations in the physical parameters between Copernicus A and the sun are essentially due to the different stellar masses. This is also reflected in the position of the stars to one another on the main sequence. The mass of Copernicus A is about 0.95 solar masses. Therefore, the star will remain in the main sequence for about 12 billion years, which is almost a billion years longer than the sun.

At the end of its life, Copernicus A will use up its supply of hydrogen and reach the state of a red giant that will devour the inner planets and eventually end up as a white dwarf .

Copernicus B

Copernicus B, distant 1065  AU from Copernicus A, is a red dwarf star of the spectral class M3. Its mass corresponds to 0.13 solar masses and the diameter is 0.3 solar diameter. The resulting weak luminosity accounts for about 1% of the luminosity of Copernicus A. While not certain, there is evidence that Copernicus B itself is a binary star system .

Surname Diameter
[million km] 		Radius
[R ☉ ] 		Mass
[M ☉ ] 		Luminosity
[L ☉ ] 		Spectral class
Copernicus A 1.32 0.96 0.95 0.63 G8 V
Copernicus B 0.42 0.30 0.13 0.0076 M3.5-4V
Sun 1.39 1.0 1.0 1.0 G2 V

Planets

Copernicus A is orbited by at least five planets . They can be divided into four inner and one outer planets. They were originally named - as usual - in the order in which they were discovered: 55 Cancri b, -c, -d, -e and -f . In December 2015, the planets and their central star were given official names by the International Astronomical Union after a public vote . It was named after astronomers and opticians of the Renaissance, following a proposal by the Koninklijke Nederlandse Vereniging voor Weeren Sterrenkunde .

Planet
(according to the distance from the central star) 		Discovery year Mass
(in M J ) 		Cycle time
(in days) 		Major semi-axis
(in AU) 		eccentricity
Janssen (55 Cancri e) 2004 0.0255 0.7365 0.0154 0.028
Galileo (55 Cancri b) 1996 0.84 14.65 0.113 0.002
Brahe (55 Cancri c) 2002 0.178 44.37 0.237 0.072
Harriot (55 Cancri f) 2007 0.148 261 0.773 0.08
Lipperhey (55 Cancri d) 2002 3.86 4870 5.446 0.027

With increasing distance from their central star they are:

Comparison of the apparent sizes and brightnesses of Copernicus A.
Planetary system of Copernicus A and our solar system in comparison.
Comparison of the respective inner planetary orbits.

Janssen

Janssen is an exoplanet whose mass (0.034 Jupiter masses) is exactly on the border between gas giants and Earth-like planets . So it could be that this planet is a kind of " super earth ". It moves around its central star in just 18 hours, with an eccentricity of 0.07. The surface is probably shaped by volcanoes and lava flows, if the planet has a solid surface.

Even if the planet is Earth-like, at only 0.016 astronomical units, it is far too close to its star for life to exist on it. The surface temperature should be 1200 ° C at this distance. Janssen was discovered in 2004.

Galileo

The planet Galileo was discovered in 1996 as the first planet in the system. Its mass corresponds to approximately 0.82 the mass of Jupiter . Its orbit has a semi-major axis of 0.115 AU and an eccentricity of 0.014. The orbital period is 14.65 days.

Brahe

The planet Brahe was discovered in 2002. Its mass corresponds to 0.16 Jupiter's masses, which makes it slightly smaller than Saturn. Its approximately circular orbit ( eccentricity of about 0.086) has a semi-major axis of 0.24 AU. This corresponds to a rotation time of 44.34 days.

Harriot

On 6 November 2007 an American team of astronomers has with Harriot fifth planet around Copernicus A discovered. There could be liquid water on it since it is in the habitable zone . However, it is likely a gas giant , but it could have orbiting moons that could have a solid surface.

The newly discovered planet has about half the mass of our Saturn and orbits its sun Copernicus A in 260 days.

Lipperhey

The planet Lipperhey was discovered in 2002. Its mass is about 3.8 Jupiter's masses. Lipperhey is more massive than the other four planets combined and could play a similar stabilizing role for the planetary system as Jupiter does in the solar system. With a semi-major axis of 5.77 AU and an eccentricity of about 0.025, 55 Cancri d is also almost at the same distance as Jupiter. The orbital period is around 5218 days.

See also

Web links

Commons : 55 Cancri  - collection of images, videos and audio files

Individual evidence

  1. ↑ Marcy, G. et al .: A planet at 5 AU Around 55 Cancri . In: The Astrophysical Journal . 581, No. 2, 2002, pp. 1375-1388. doi : 10.1086 / 344298 .
  2. ^ Eggenberger, A. et al .: Planets in Binaries . ( PostScript ) In: Scientific Frontiers in Research on Extrasolar Planets, ASP Conference Series . 294, 2003, pp. 43 - 46.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www-lep.gsfc.nasa.gov  
  3. ^ Raghavan, D. et al .: Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems . In: The Astrophysical Journal . 646, 2006, pp. 523-542. doi : 10.1086 / 504823 .
  4. ^ Fischer, DA et al .: Five Planets Orbiting 55 Cancri . In: The Astrophysical Journal . 675, 2008, pp. 790-801. doi : 10.1086 / 525512 .
  5. ↑ 55 Cnc (English) - Entry in Extrasolar Planets Encyclopaedia
  6. ↑ International Astronomical Union: NameExoWorlds - The Approved Names. Retrieved January 3, 2016 .
  7. ^ Solar system with at least five planets - Article at pro-physik.de , November 8, 2007