FY 380

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Star
GJ 380
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Big Bear
Right ascension 10 h 11 m 22.14 s
declination + 49 ° 27 ′ 15.2 ″
Apparent brightness 6.61 (6.59 to 6.66) mag
Typing
rel. Brightness
(G-band) 		5.95 ± 0.01 mag
rel. Brightness
(J-band) 		3.97 likes
B − V color index 1.36 
U − B color index 1.28 
R − I index 0.60 
Spectral class K7 Ve
Variable star type supposed 
Astrometry
Radial velocity (−25.73 ± 0.1) km / s
parallax (205.39 ± 0.03)  mas
distance (15.87)  ly
(4.87)  pc
Proper movement 
Rec. Share: (−1362.335 ± 0.049)  mas / a
Dec. portion: (−505.666 ± 0.055)  mas / a
Physical Properties
Dimensions (0.670 ± 0.033)  M ☉
radius (0.605 ± 0.020)  R ☉
Effective temperature (4050)  K.
Other names
and catalog entries
Bonn survey BD + 50 ° 1725
Henry Draper Catalog HD 88230 [1]
Gliese catalog FY 380 [2]
Hipparcos catalog HIP 49908 [3]
SAO catalog SAO 43223 [4]
Tycho catalog TYC 3437-811-1 [5]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J10112218 + 4927153 [6]
Other names Groombridge 1618 • 1RXS J101124.1 + 492718 • CCDM J10114 + 4927A • GC 13987 • IRAS 10082 + 4942 • UBV 9470 • USNO-B1.0 1394-00210100

Template: Infobox star / maintenance / magGTemplate: Infobox star / maintenance / magJ

GJ 380 ( Groombridge 1618 ) is a later main sequence star of the spectral class K7. It is located in the constellation Great Bear and, at a distance of about 15 light years, is one of the stars closest to Earth .

properties

The star has about 67% of the solar mass , 60% of the solar radius, and the surface temperature is as low as 4000 K . It shines orange-red. This star has only about 4.6% of the sun's luminosity. GJ 380 is probably a flare star , but it is very luminous compared to other flare stars. It has a rotation speed of about 2.8 km / s.

Since 1989 it has been suggested that GJ 380 has a planet . However, a 2010 study could not find any evidence for the proposed planet either.

Power generation and further development

GJ 380 is one of the main sequence stars that generate their energy through the proton-proton chain . In its core it converts hydrogen to helium and is relatively stable. Since the star has only 67% of the solar mass, it will linger on the main sequence much longer than the sun; while the sun lingers on the main sequence for about 10 billion years, at GJ 380 it will be about 25 billion years. After that it will reach a core temperature of around 100 million degrees Celsius and the helium will start burning in the core ; the burning of hydrogen in the outer layers . The star swells into a red giant . Since GJ 380 has more than 0.5 solar masses, the star is able to produce helium through the three-alpha process . Later, when the star has used up its helium, it will repel its outer layers in the form of a planetary nebula and what remains is a white dwarf , which then cools down to a black dwarf .

Individual evidence

  1. ↑ a b c d e f g HD 88230. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed April 20, 2019 .
  2. ↑ a b NSV 4765. In: VSX. AAVSO , accessed April 20, 2019 .
  3. ↑ a b c Nearby Stars, Preliminary 3rd Version (Gliese + 1991)
  4. ↑ a b c Ignasi Ribas: Masses and Radii of Low-Mass Stars: Theory Versus Observations . In: Astrophysics and Space Science . 304, No. 1-4, 2006, pp. 89-92. arxiv : astro-ph / 0511431 . bibcode : 2006Ap & SS.304 ... 89R . doi : 10.1007 / s10509-006-9081-4 .
  5. ↑ a b Mark J. Pecaut, Eric E. Mamajek: Intrinsic Colors, Temperatures, and bolometric Corrections of pre-Main Sequence Stars . In: The Astrophysical Journal Supplement Series . 2013. arxiv : 1307.2657 . bibcode : 2013ApJS..208 .... 9P . doi : 10.1088 / 0067-0049 / 208/1/9 .
  6. ↑ S. Ertel, D. Defrère u. a .: The HOSTS Survey — Exozodiacal Dust Measurements for 30 Stars. In: The Astronomical Journal. 155, 2018, p. 194, doi : 10.3847 / 1538-3881 / aab717 .
  7. ↑ Geoffrey W. Marcy, Karsten J. Benitz: A search for substellar companions to low-mass stars . In: The Astrophysical Journal , Part 1 . 344, No. 1, 1989, pp. 441-453. bibcode : 1989ApJ ... 344..441M . doi : 10.1086 / 167812 .
  8. ↑ AN Heinze, Philip M. Hinz, Suresh Sivanandam, Matthew Kenworthy, Michael Meyer, Douglas Miller: Constraints on Long-period Planets from an L'- and M-band Survey of Nearby Sun-like Stars: Observations . In: The Astrophysical Journal . 714, No. 2, May 2010, pp. 1551-1569. arxiv : 1003.5340 . bibcode : 2010ApJ ... 714.1551H . doi : 10.1088 / 0004-637X / 714/2/1551 .