70 Ophiuchi

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Double star
70 Ophiuchi
Observation
dates equinox :  J2000.0 , epoch : J2000.0
AladinLite
Constellation Snake bearer
Apparent brightness  4.03 mag
Astrometry
parallax 196.72 ± 0.83 mas
distance  16.58 ± 0.07 ly
(5.08 ± 0.02 pc )
Proper movement :
Rec. Share: 124.16 mas / a
Dec. portion: −962.82 mas / a
orbit 
period 88.3 a
Major semi-axis 4.56 "
eccentricity 0.495
Orbit inclination 120.8 °
Argument of the node 301.4 °
Epoch of the periastron 1984.3
Argument of the periapsis 13.2 °
Individual data
Names A; B.
Observation data:
Right ascension A. 180527.37118 h 05 m 27,371 s
B. 180527.42118 h 05 m 27.421 s
declination A. 2022959.32+ 2 ° 29 ′ 59.32 ″
B. 2022956.42+ 2 ° 29 ′ 56.42 ″
Apparent brightness A. 4.20 mag
B. 6.00 likes
Typing:
Spectral class A. K0V
B. K4V
B − V color index A. 0.78
U − B color index A. 0.57
Physical Properties:
Absolute vis.
Brightness M vis 		A. 5.5 mag
B. 7.47 likes
Dimensions A. 0.90 ± 0.04 M ☉
B. 0.70 ± 0.07 M ☉
radius A. 0.91 ± 0.03 R ☉
B.
Luminosity A. 0.59 ± 0.02 L ☉
B. 0.13 ± 0.03 L ☉
Effective temperature A. 5,300 K
B. 4,350 ± 150 K
Metallicity [Fe / H] A. +0.04
B.
Rotation time A. 19.7 d
B.
Other names
and catalog entries
Flamsteed name 70 Oph
Bonn survey BD +02 3482
Bright Star Catalog HR 6752 [1]
Henry Draper Catalog HD 165341 [2]
Hipparcos catalog HIP 88601 [3]
Bonn survey BD +02 3482A BD +02 3482B
Henry Draper Catalog HD 165341A HD 165341B
Tycho catalog TYC 434-5213-1 [4] TYC 434-5212-1 [5]
WDS catalog WDS J18055 + 0230AB
Further designations: V2391 Oph, GJ 702

Template: Infobox double star / maintenance / RekDekSizeLeerTemplate: Infobox double star / maintenance / single coordinates

70 Ophiuchi is a binary star system in 16.6 light years away from the sun . It is visible to the naked eye as a 4th magnitude star in the constellation of the Serpent Bearer.

properties

Both components are main sequence stars of the spectral class K. The primary component is a yellowish-orange BY-Draconis star of the spectral class K0, the secondary component is a main sequence star of the spectral class K4. The two stars orbit each other at an average distance of 23.3 AU . Because of the very eccentric orbit, the distance between them varies from 11.4 to 34.8 AU. The orbital period is 83.38 years.

history

The system was first cataloged by Wilhelm Herschel in his work on binary stars in the late 18th century . Herschel proved that it was a double system held together by gravity, within which both stars revolve around a common center of mass. This was an important contribution to the proof that Newton's law of gravity also applies to objects outside the solar system . Herschel also suspected that a third invisible companion might influence the orbit of the two visible stars.

distance

Determining the distance for 70 ophiuchi
source Parallax (mas) Distance (pc) Distance (Lj) Distance ( Pm )
Woolley et al. (1970) 195 ± 5 5.13 ± 0.13 16.7 ± 0.4 158.2 +4.2−4
Gliese & Jahreiß (1991) 199.0 ± 3.6 5.03 ± 0.09 16.39 +0.3−0.29 155.1 +2.8−2.9
van Altena et al. (1995) 199.7 ± 3.4 5.01 +0.09−0.08 16.33 +0.28−0.29 154.5 +2.7−2.6
Perryman et al. (1997) (Hipparcos) 196.62 ± 1.38 5.09 ± 0.04 16.59 ± 0.12 156.9 ± 1.1
Perryman et al. (1997) (Tycho)
Söderhjelm (1999) 195.7 ± 0.9 5.11 +0.024−0.023 16.67 ± 0.08 157.7 ± 0.7
van Leeuwen (2007) 196.72 ± 0.83 5.083 +0.022−0.021 16.58 ± 0.07 156.9 ± 0.7
RECONS TOP100 (2012) 195.96 ± 0.87 5.103 ± 0.023 16.64 ± 0.07 157.5 ± 0.7

Non-trigonometric distance determinations are marked in italics . The most precise determination is marked in bold .

Assumed planetary system

In 1855, WS Jacob of the British East India Company's Madras Observatory claimed that the pair's orbit was anomalous and that it was highly likely that a planetary body was in communication with the system. The American astronomer Thomas Jefferson Jackson See also put forward the thesis in 1899 that a dark companion existed, but his compatriot and professional colleague Forest Ray Moulton was able to prove shortly afterwards that a three-body system with the specific orbital properties would be highly unstable. Both Jacob's and See's theses turned out to be flawed. WS Jacob was possibly the first to assume the existence of an exoplanet based on astrometric evidence.

In 1943, Dirk Reuyl ( Peter van de Kamp's cousin ) and Erik Holberg again made the claim that they had detected a planetary system. In their opinion, the companion would have had an estimated one-tenth the mass of the sun . This was perceived as a sensation at the time, but was refuted again on the basis of later observations.

Even so, the possibility of planets in the system cannot be completely ruled out. In 2006, astronomers from the McDonald Observatory concluded that one or more planets with masses between 0.46 and 12.8 Jupiter's masses could exist at a mean distance between 0.05 and 5.2 AU.

Web links

Individual evidence

  1. ↑ a b SIMBAD: 70 Oph. Retrieved May 24, 2015 .
  2. ↑ a b c SIMBAD: 70 Oph A. Retrieved May 24, 2015 .
  3. ↑ a b c d SIMBAD: 70 Oph B. Accessed May 24, 2015 .
  4. ^ Van Leeuwen, F .: Validation of the new Hipparcos reduction . August 13, 2007, arxiv : 0708.1752 .
  5. ^ Heintz, WD: The binary star 70 Ophiuchi revisited . June 1988, bibcode : 1988JRASC..82..140H .
  6. ↑ a b c Fernandes, J .; Lebreton, Y .; Baglin, A .; Morel, P .: Fundamental stellar parameters for nearby visual binary stars: eta Cas, XI Boo, 70 OPH and 85 Peg. Helium abundance, age and mixing length parameters for low mass stars . October 1998, bibcode : 1998A & A ... 338..455F .
  7. ↑ a b Bruntt, H. et al .: Accurate fundamental parameters for 23 bright solar-type stars . February 23, 2010, arxiv : 1002.4268 .
  8. ↑ Morell, O .; Kallander, D .; Butcher, HR: The age of the Galaxy from thorium in G dwarfs, a re-analysis . June 1992, bibcode : 1992A & A ... 259..543M .
  9. ↑ a b Maldonado, J. et al .: A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups . July 7, 2010, arxiv : 1007.1132 .
  10. ↑ General Catalog of Variable Stars: V2391 Oph. Retrieved May 24, 2015 .
  11. ↑ Solstation.com: 70 Ophiuchi 2? Retrieved May 24, 2015 .
  12. ↑ a b See, TJJ: Researches on the orbit of 70 Ophiuchi, and on a periodic perturbation in the motion of the system arising from the action of an unseen body . January 1896, bibcode : 1896AJ ..... 16 ... 17S .
  13. ^ Woolley R .; Epps EA; Penston MJ; Pocock SB: Woolley 702. Retrieved May 24, 2015 .
  14. ↑ Gliese, W. and Jahreiß, H. (1991): Gl 702. Retrieved on May 24, 2015 .
  15. ^ Van Altena WF, Lee JT, Hoffleit ED: GCTP 4137. Retrieved April 24, 2015 .
  16. ↑ Perryman et al .: HIP 88601. Retrieved May 24, 2015 .
  17. ↑ Perryman et al .: HIP 88601. Retrieved May 24, 2015 .
  18. ↑ Söderhjelm, Staffan: HIP 88601. Retrieved May 24, 2015 .
  19. ^ Van Leeuwen F .: HIP 88601. Retrieved April 24, 2015 .
  20. ↑ RECONS: THE ONE HUNDRED NEAREST STAR SYSTEMS. Retrieved May 24, 2015 .
  21. ^ Jacob, WS: On certain anomalies presented by the Binary Star 70 Ophiuchi . June 1855, bibcode : 1855MNRAS..15..228J .
  22. ↑ Sherrill, Thomas J .: A Career of controversy: the anomaly OF TJJ See. (PDF) Archived from the original on September 25, 2007 ; accessed on May 24, 2015 .
  23. ↑ a b Heintz, WD: The binary star 70 Ophiuchi revisited . June 1988, bibcode : 1988JRASC..82..140H .
  24. ↑ Reuyl, D .; Holmberg, E .: On the Existence of a Third Component in the System 70 Ophiuchi . January 1943, bibcode : 1943ApJ .... 97 ... 41R .
  25. ↑ Wittenmyer; Endl, Michael; Cochran, William D .; Hatzes, Artie P .; Walker, GAH; Yang, SLS; Paulson, Diane B .: Detection Limits from the McDonald Observatory Planet Search Program . April 7, 2006, arxiv : astro-ph / 0604171 .