HD 190228

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**HD 190228**
Observation data Epoch J2000.0
Constellation (pronunciation)	Vulpecula
Right ascension	20h 03m 00.7730s
Declination	+28º 18' 24.6847″
Apparent magnitude (V)	7.307
Absolute magnitude (V)	3.341
Distance	202.58 ly (62.11 pc)
Spectral type	G5IV
Other designations
BD+27 3593, HIP 98714, SAO 88118

HD 190228 is a star located in the constellation Vulpecula. Its apparent magnitude is 7.31 and the absolute magnitude is 3.34. The distance is 203 light years or 62 parsecs or 1.92 exameters from our home planet. It is a yellow subgiant meaning this star behaves like a main-sequence but the hydrogen fuel is scarce. The star is definitely old with age over 10 billion years and it is metal-poor. This star is also called by the Hipparcos number 98714.

[edit] HD 190228 b

**HD 190228 b**
Discovery
Discovered by	Sivan et al.
Discovery site	USA
Discovery date	2001
Detection method	Radial Velocity
Designations
Alternative names	HIP 98714 b SAO 88118 b
Orbital characteristics
Semi-major axis	2.25 AU
Eccentricity	0.499±0.030
Orbital period	1146±16 d
Average orbital speed	21.4 km/s
Angular distance	36.23 mas
Longitude of periastron	100.7±3.0°
Time of periastron	2451236±25 JD
Semi-amplitude	91±5 m/s
Physical characteristics
Mass	>4.49 M_J

HD 190228 b is an 1146-day period extrasolar planet with mass 4.49 Jupiter mass or 8.52 wekagrams. The mass is minimum since inclination is unknown. This gas giant planet orbits at 2.25 astronomical units or 336 gigameters or 10.9 microparsecs. The orbital eccentricity is 49.9%, meaning the orbital distance range from 1.13 AU to 3.37 AU. The average speed of the orbiting planet is approximately 21.4 km/s and have semi-amplitude of 91 m/s.

As it is typical for most known extrasolar planets, this planet was found by using radial velocity method. Sivan discovers this planet in 2001 in USA.