19h28m32.887s, +42° 25′ 45.91″
| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h28m 32.8905s[2] |
| Declination | +42° 25′ 45.959″[2] |
| Apparent magnitude (V) | 15.306[3] |
| Characteristics | |
| Spectral type | M0V[4] |
| Astrometry | |
| Radial velocity (Rv) | −26.99±6.00[2] km/s |
| Proper motion (μ) | RA: −0.463(21) mas/yr[2] Dec.: 11.691(21) mas/yr[2] |
| Parallax (π) | 2.2537 ± 0.0185 mas[2] |
| Distance | 1,450 ± 10 ly (444 ± 4 pc) |
| Details | |
| Mass | 0.684±0.026[5] M☉ |
| Radius | 0.664±0.013[5] R☉ |
| Temperature | 4499±75[5] K |
| Metallicity [Fe/H] | −0.17±0.11[4] dex |
| Rotation | 17.951±0.016 days[6] |
| Rotational velocity (v sin i) | 0.6[3] km/s |
| Age | 2.2[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| KIC | data |
Kepler-28 is an M-type main-sequence star about 1,450 light-years (440 parsecs) away in the northern constellationofCygnus.[2] With an apparent visual magnitude of 15.036,[3] this star is too faint to be seen with the naked eye. It is orbited by two exoplanets.
The two transiting planets of Kepler-28 were discovered in 2011 using the Kepler space telescope, and were confirmed in early 2012.[9] They are both warm sub-Neptune gas planets.[7] The planetary parameters were updated in 2023, with lower values for all of mass, radius, and density compared to previous estimates.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 1.63+0.51 −0.40 M🜨 |
0.062 | 5.91213(17) | <0.08 | — | 1.959+0.043 −0.042 R🜨 |
| c | 2.06+0.70 −0.52 M🜨 |
0.081 | 8.98597(27) | 0.017+0.023 −0.014 |
— | 1.857±0.042 R🜨 |
