Helvetios (star)

Database links to 51 Pegasi

Star Helvetios
The red circle marks the position of Helvetios (51 Pegasi) in the constellation Pegasus.
AladinLite
Observation dates equinox :  J2000.0 , epoch : J2000.0
Constellation	Pegasus
Right ascension	22 h 57 m 27.98 s
declination	+ 20 ° 46 ′ 7.8 ″
Apparent brightness	5.46 likes
Typing
Known exoplanets	1
B − V color index	0.67
U − B color index	0.21
R − I index	0.34
Spectral class	G2 IV
Astrometry
Radial velocity	(−33.24 ± 0.43) km / s
parallax	(64.65 ± 0.12)  mas
distance	(50.43 ± 0.09)  ly (15.47 ± 0.03)  pc
Visual absolute brightness M vis	+4.51 mag
Proper movement
Rec. Share:	(207.36 ± 0.21)  mas / a
Dec. portion:	(62.09 ± 0.17)  mas / a
Physical Properties
Dimensions	(1.158 ± 0.058)  M ☉
radius	(1.183 ± 0.059)  R ☉
Luminosity	1.30  L ☉
Effective temperature	(5793 ± 70)  K.
Metallicity [Fe / H]	(0.2 ± 0.07)
Rotation time	3 - 7 Days
Age	(4.0 ± 2.5) 10 9  a
Other names and catalog entries
Flamsteed name 51 pegasi Bonn survey BD + 19 ° 5036 Bright Star Catalog HR 8729 [1] Henry Draper Catalog HD 217014 [2] Gliese catalog FY 882 [3] Hipparcos catalog HIP 113357 [4] SAO catalog SAO 90896 [5] Tycho catalog TYC 1717-2193-1 [6] 2MASS catalog 2MASS J22572795 + 2046077 [7] Other names NLTT 55385 • USNO-B1.0 1107-00589893

Helvetios ( 51 Pegasi ) is a sun-like star in the constellation Pegasus, 50 light-years away . Its apparent brightness is 5.46 mag, so that it can barely be seen with the naked eye on dark nights. Its mass is about 10% higher than that of the sun and it has a greater metallicity than it because its hydrogen supplies are slowly running out.

Around Helvetios, Michel Mayor and Didier Queloz from the Department of Astronomy at the University of Geneva discovered the first planet outside the solar system ( exoplanet ) that orbits a sun-like star. The planet called Dimidium has about 0.46 Jupiter masses and orbits the star in about 4.2 days at a distance of only 0.052 astronomical units (AU). A second planet was suspected.

The star was named Helvetios by the IAU on December 15, 2015 after a public competition to name exoplanets and their central stars . The name proposed by the youth group of the Lucerne Astronomical Society is Latin and refers to the Celtic tribe of the Helvetii , who settled in what is now Switzerland .

Individual evidence

1. ↑ ^{a b c d e} 51 Peg. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed April 20, 2019 . 
2. ↑ ^{a b c} Bright Star Catalog
3. ↑ ^{a b c d} 51 Peg b. In: Extrasolar Planets Encyclopaedia . Retrieved April 20, 2019 . 
4. ↑ ^{a b} P. E. Kervella, F. Arenou, F. Mignard, F. Thévenin: Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly . In: Astronomy & Astrophysics . 623, p. A72. arxiv : 1811.08902 . bibcode : 2019A & A ... 623A..72K . doi : 10.1051 / 0004-6361 / 201834371 .
5. ^ University Corporation for Atmospheric Research: Will a Second Planet Be Discovered around 51 Pegasi? - NCAR Data Suggest Not a Giant One. (No longer available online.) Archived from the original on May 7, 2013 ; accessed on May 9, 2015 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
6. ↑ International Astronomical Union: NameExoWorlds - The Approved Names. Retrieved January 3, 2016 . 

Web links

Commons : Helvetios (star)  - collection of images, videos and audio files

• SolStation.com: 51 Pegasi. Retrieved May 12, 2015 .