HAT-P-27
{{Short description|Star in the constellation Virgo}}
{{Starbox begin
| name = HAT-P-27
}}
{{Starbox observe
| epoch = J2000
| constell = Virgo
}}
{{Starbox character
| type = main-sequence star
}}
{{Starbox astrometry
| prop_mo_ra = {{val|−28.610|(19)}}
| prop_mo_dec = {{val|−2.774|(19)}}
| parallax = 4.952
| p_error = 0.0169
}}
{{Starbox orbit
| primary = HAT-P-27
| name = HAT-P-27 B
| period =
| period_unitless =
| axis = 0.656{{±|0.021}}
| axis_unitless = 131 AU
| eccentricity =
| inclination =
| node =
| periastron =
| periarg =
| periarg_primary =
| k1 =
| k2 =
}}
{{Starbox detail
| mass = 0.945{{±|0.035}}
| radius = 0.898{{±|0.054|0.039}}
| gravity = 4.51{{±|0.04}}
| luminosity = 0.57{{±|0.09|0.07}}
| temperature = 5300{{±|90}}
| metal_fe = 0.29{{±|0.10}}
| rotation = 0.4{{±|0.4}}
| rotational_velocity =0.6{{±|0.7|0.4}}
| age_gyr = 4.4{{±|3.8|2.6}}
}}
{{Starbox catalog
| names = HAT-P-27, {{odlist|WASP=40|GSC=00333-00351|2MASS=J14510418+0556505|Gaia DR2=1159336403336463872}}
}}
{{Starbox reference
| Simbad = HAT-P-27
}}
{{Starbox end}}
HAT-P-27, also known as WASP-40, is the primary of a binary star system about 659 light-years away. It is a G-type main-sequence star. The star's age is similar to the Sun's at 4.4 billion years. HAT-P-27 is enriched in heavy elements, having a 195% concentration of iron compared to the Sun.
The very dim stellar companion was detected in 2015 at a projected separation of 0.656″ and proven to be physically bound to the system in 2016.
Planetary system
In 2011 a transiting hot Jupiter type planet b was detected in a mildly eccentric orbit. The planetary equilibrium temperature is 1207{{±|41}} K. The survey in 2013 failed to find any Rossiter-McLaughlin effect and therefore was unable to constrain the inclination of planetary orbit to the equatorial plane of the parent star. No orbital decay was detected as in 2018, despite the close proximity of the planet to the star.
The presence of an additional planet in the system has been suspected since 2015.
In 2024, a detection of a possible Neptune-like planet was reported. It is expected to be analog with Neptune in terms of radius, although is much hotter due to the low orbital separation, one year in this planet last one day and five hours, causing the planetary equilibrium temperature to be {{convert|1426|K|C|lk=in}}. More observations are needed to validate its existence.
{{OrbitboxPlanet begin
}}
{{OrbitboxPlanet
| exoplanet = b
| mass = 0.660{{±|0.033}}
| radius = 1.038{{±|0.077|0.058}}
| semimajor = 0.0403{{±|0.0005}}
| period = 3.039586{{±|0.000012}}
| eccentricity = 0.078{{±|0.047}}
}}
{{Orbitbox planet hypothetical
| exoplanet = c
| mass_earth = 17.8{{+-|13.8|0.81}}
| radius_earth = 4.33{{+-|0.44}}
| semimajor =
| period = {{val|1.1994|(2)}}
| eccentricity = <0.19
| inclination =
}}
{{Orbitbox end}}
References
{{Reflist|refs=
{{Cite Gaia DR2|1159336403336463872}}
{{Cite Gaia DR3|1159336403336463872}}
{{cite simbad |title=HAT-P-27}}
{{cite constellation|HAT-P-27}}
{{Cite journal |last1=Dévora-Pajares |first1=Martín |title=The SHERLOCK pipeline: new exoplanet candidates in the WASP-16, HAT-P-27, HAT-P-26, and TOI-2411 systems |arxiv=2407.14602 |doi=10.1093/mnras/stae1740 |last2=Pozuelos |first2=Francisco J. |last3=Thuillier |first3=Antoine |last4=Timmermans |first4=Mathilde |last5=Van Grootel |first5=Valérie |last6=Bonidie |first6=Victoria |last7=Mota |first7=Luis Cerdeño |last8=Suárez |first8=Juan C.|date=2024 |doi-access=free |journal=Monthly Notices of the Royal Astronomical Society |volume=532 |issue=4 |pages=4752–4773 }}
}}
{{Sky|14|51|04.1870|+|05|56|50.5482}}
{{Virgo (constellation)}}
{{DEFAULTSORT:HAT-P-27}}
Category:Virgo (constellation)
Category:G-type main-sequence stars
Category:Planetary systems with one confirmed planet