HAT-P-27
Star in the constellation Virgo
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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.[3] HAT-P-27 is enriched in heavy elements, having a 195% concentration of iron compared to the Sun.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Virgo[1] |
| Right ascension | 14h 51m 04.1870s[2] |
| Declination | +05° 56′ 50.549″[2] |
| Apparent magnitude (V) | 12.214[3] |
| Characteristics | |
| Evolutionary stage | main-sequence star[4] |
| Spectral type | G8[4] |
| Astrometry | |
| Radial velocity (Rv) | −16.74±0.56[2] km/s |
| Proper motion (μ) | RA: −28.610(19) mas/yr[2] Dec.: −2.774(19) mas/yr[2] |
| Parallax (π) | 4.9528±0.0169 mas[2] |
| Distance | 659 ± 2 ly (201.9 ± 0.7 pc) |
| Orbit[5] | |
| Primary | HAT-P-27 |
| Name | HAT-P-27 B |
| Semi-major axis (a) | 0.656±0.021" (131 AU) |
| Details[3] | |
| Mass | 0.945±0.035 M☉ |
| Radius | 0.898+0.054 −0.039 R☉ |
| Luminosity | 0.57+0.09 −0.07 L☉ |
| Surface gravity (log g) | 4.51±0.04 cgs |
| Temperature | 5300±90 K |
| Metallicity [Fe/H] | 0.29±0.10 dex |
| Rotation | 0.4±0.4 |
| Rotational velocity (v sin i) | 0.6+0.7 −0.4[6] km/s |
| Age | 4.4+3.8 −2.6 Gyr |
| Other designations | |
| HAT-P-27, TOI-5672, TIC 461239485, WASP-40, GSC 00333-00351, 2MASS J14510418+0556505[7] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
A very dim stellar companion was detected in 2015 at a projected separation of 0.656″[5] and proven to be physically bound to the system in 2016.[4]
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.[3] A 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.[6] No orbital decay was detected as of 2018, despite the close proximity of the planet to the star.[8]
The presence of an additional planet in the system has been suspected since 2015.[9]
In 2024, a detection of a possible Neptune-like planet was reported. It is expected to be an analog of Neptune in terms of radius, although much hotter due to the low orbital separation; one year on this planet lasts one day and five hours, causing the planetary equilibrium temperature to be 1,426 K (1,153 °C). More observations are needed to validate its existence.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | 0.660±0.033 MJ | 0.0403±0.0005 | 3.039586±0.000012 | 0.078±0.047 | 85.0±0.2[6] | 1.038+0.077 −0.058 RJ |
| c (unconfirmed) | 17.8+13.8 −0.81 M🜨 |
— | 1.1994(2) | <0.19 | — | 4.33±0.44 R🜨 |