Lacaille 9352

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Star
Lacaille 9352
AladinLite
Observation
dates equinoxJ2000.0 , epoch : J2000.0
Constellation Southern fish
Right ascension 23 h 05 m 52.04 s
declination -35 ° 51 ′ 11.1 ″
Apparent brightness 7.34 likes
Typing
B − V color index (1.48) 
U − B color index (1.16) 
Spectral class M0.5 V
Astrometry
Radial velocity (8.17 ± 0.14) km / s
parallax (304.22 ± 0.05)  mas
distance (10.71 ± 0.01)  ly
(3.28 ± 0.01)  pc
Proper movement 
Rec. Share: (+6766.00 ± 0.07)  mas / a
Dec. portion: (+1330.39 ± 0.08)  mas / a
Physical Properties
Dimensions (0.503 ± 0.025)  M
radius (0.459 ± 0.011)  R
Effective temperature (3700)  K
Metallicity [Fe / H] (−0.22)
Other names
and catalog entries
Cordoba Survey CD −36 ° 15693
Henry Draper Catalog HD 217987 [1]
Gliese catalog FY 887 [2]
Hipparcos catalog HIP 114046 [3]
SAO catalog SAO 214301 [4]
2MASS catalog 2MASS J23055131-3551130 [5]
Other names LHS 70

Lacaille 9352 (Lac 9352) is a star in the constellation Piscis Austrinus . With an apparent magnitude of 7.34 mag, the star shines too weakly to be seen with the naked eye. Lacaille 9352 is 3.3 parsecs from Earth, making it one of the closest stars to the Sun.

properties

With 6.9 arc seconds per year, the star has the fourth highest known proper motion . The space velocity components of the star are (U, V, W) = (-93.9, -14.1, -51.4) km / s.

Lacaille 9352 is a red dwarf belonging to the spectral class M0.5. Lacaille 9352 was the first red dwarf to have angular diameter measured, with the physical diameter being approximately 46% of the radius of the sun . The star has about half the mass of the Sun and an effective temperature of around 3700 K.

Planetary system

With the help of the HARPS spectrograph at the European Southern Observatory , scientists from the RedDots astronomical team, headed by the University of Göttingen , succeeded in discovering a planetary system around Lacaille 9352 in 2020. Using the radial velocity method, they found two planets, Gliese 887b and Gliese 887c, with orbits of only 9.3 and 21.8 days, respectively. Both planets are within the habitable zone and the star is not very active, so it could be that both planets have retained their atmosphere and may harbor life. Also, since the star's brightness is relatively constant, this makes it easy to see the super-earth system's atmospheres . This fact makes it a primary target for the James Webb Space Telescope , a successor to the Hubble telescope .

See also

Web links

Individual evidence

  1. a b c d e SIMBAD : HD 217987. Accessed July 14, 2018 .
  2. a b c d e f g h i j k Demory et al .: Mass-radius relation of low and very low-mass stars revisited with the VLTI . In: Astronomy & Astrophysics . tape 505 , no. 1 , 2009, p. 205-215 , doi : 10.1051 / 0004-6361 / 200911976 , arxiv : 0906.0602 .
  3. ^ AWJ Cousins: UBV photometry of some southern stars . In: Monthly Notes of the Astronomical Society of Southern Africa . 32, 1973, p. 11. bibcode : 1973MNSSA..32 ... 11C .
  4. ^ F. van Leeuwen: Validation of the new Hipparcos reduction . In: Astronomy & Astrophysics . 474, No. 2, November 2007, pp. 653-664. bibcode : 2007A & A ... 474..653V . doi : 10.1051 / 0004-6361: 20078357 .
  5. ^ Research Consortium on Nearby Stars: The One Hundred Nearest Star Systems . Georgia State University. Retrieved December 18, 2017.
  6. ^ High Proper Motion Stars in the Hipparcos Catalog . European Space Agency. July 1, 2007. Retrieved January 20, 2010.
  7. ARICNS star page of Lacaille 9352 . Astronomical Computing Institute Heidelberg. Retrieved April 16, 2010.
  8. ^ Giant Eyes for the VLT Interferometer , European Southern Observatory. Retrieved January 20, 2010. 
  9. ^ Jeffers et al .: A multiple planet system of super-Earths orbiting the brightest red dwarf star GJ887 . University of Goettingen. Retrieved June 26, 2020.