KOI-54

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Double star
KOI-54
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation swan
Right ascension 19 h 46 m 15.53 s
declination + 43 ° 56 ′ 51.3 ″
Apparent brightness (+8.39 ± 0.01) mag
Typing
B − V color index (0.14) 
Spectral class A0
Variable star type HB 
Astrometry
Radial velocity (−14.88 ± 0.21) km / s
parallax 2.97 ± 0.03  mas
distance (1098 ± 11)  ly
(337)  pc
Proper movement 
Rec. Share: (17.49 ± 0.06)  mas / a
Dec. portion: (5.11 ± 0.06)  mas / a
Physical Properties
Dimensions (2.33 ± 0.1) / (2.39 ± 0.12)  M ☉
radius (2.20 ± 0.03) / (2.33 ± 0.03)  R ☉
Effective temperature (8500 ± 200) / (8800 ± 200)  K
Metallicity [Fe / H] (0.4 ± 0.2) / (0.4 ± 0.2)
Other names
and catalog entries
Bonn survey BD + 43 ° 3355
Henry Draper Catalog HD 187091 [1]
Hipparcos catalog HIP 97279 [2]
SAO catalog SAO 48816 [3]
Tycho catalog TYC 3148-1110-1 [4]
2MASS catalog 2MASS J19461553 + 4356513 [5]
Other names KOI-54, KIC 8112039

KOI-54 (also HD 187091 ) is a binary star at a distance of about 1120  light years . It belongs to the relatively newly discovered category of the so-called heartbeat stars , which belong to the variable stars .

The system consists of 2 closely circling stars with comparable radii and mass. The system shows an increase in brightness every 41.8 days, similar to the pulsations in an electrocardiogram . The two components are about 0.4 AU apart with an eccentricity of 0.83.

The system was observed with the Kepler (space telescope) over a longer period of time and classified as a KOI ( Kepler Object of Interest ). Instead of an exoplanet , this special type of star was found here.

Individual evidence

  1. ↑ a b c d e f HD 187091. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on September 3, 2018 .
  2. ↑ a b KOI-54. In: VSX. AAVSO, accessed September 3, 2018 .
  3. ↑ a b c d e William F. Welsh et. al: KOI-54: The Kepler Discovery of Tidally-Excited Pulsations and Brightenings in a Highly Eccentric Binary . In: The Astrophysical Journal Supplement Series . 197, 2011. arxiv : 1102.1730 . doi : 10.1088 / 0067-0049 / 197/1/4 .