Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Taurus [1] |
Right ascension | 04h 13m 05.6131s [2] |
Declination | +15° 14′ 52.018″ [2] |
Apparent magnitude (V) | 15.881 [3] |
Characteristics | |
Spectral type | M4.5 V [4] |
Apparent magnitude (J) | 11.303(21) [5] |
Apparent magnitude (H) | 10.732(20) [5] |
Apparent magnitude (K) | 10.444(19) [5] |
Variable type | Planetary transit [4] |
Astrometry | |
Radial velocity (Rv) | 38.64(15) [4] km/s |
Proper motion (μ) |
RA: 122.450(38)
mas/
yr
[2] Dec.: −18.603(26) mas/ yr [2] |
Parallax (π) | 22.3572 ± 0.0308 mas [2] |
Distance | 145.9 ± 0.2
ly (44.73 ± 0.06 pc) |
Details [6] | |
Mass | 0.2634(77) M☉ |
Radius | 0.2932(93) R☉ |
Luminosity | 0.00816(29) L☉ |
Temperature | 3207(58) K |
Metallicity [Fe/H] | 0.15(3) [4] dex |
Rotation | 1.87708(66) d [7] |
Rotational velocity (v sin i) | 7.71(29) [8] km/s |
Age | 650(70) [8] [9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
K2-25 is a young red dwarf star located in the Hyades cluster. There is a single known Neptune-sized planet in a 3.5 day orbit.
Using proper motion measurements in a search for low-luminosity members of the Hyades cluster, William van Altena first identified the star vA 50 (later known as K2-25) as a probable cluster member. [12] Membership in the Hyades cluster was later confirmed. [13] [14] [4]
K2-25 is a red dwarf that is only 26% the mass of the Sun and less than 1% of the luminosity. [6] As a member of the Hyades cluster, it is only 650 million years old as compared to the Sun's 4.5 billion. [8]
There is clear evidence for starspot activity in both the Kepler data and radial velocities as well as the associated activity indicators. [15]
The star has one known planet, K2-25b, with searches of the Kepler space telescope data for transits of additional planets being negative. [4] Analysis of transit-timing variations from the Spitzer Space Telescope as well as the MEarth Project also found no evidence of additional planets. [16]
Brightness measurements of K2-25 taken by the Kepler space telescope during its extended K2 mission led to the discovery of the transiting planet K2-25b. [4] [10]
K2-25b is a Hot Neptune type planet in an eccentric 3.48 day orbit. [15]
Due to its proximity and the activity levels of its host star, K2-25b should be losing some of its atmosphere to space; however, observations of two transits by the Hubble Space Telescope to search for escaping neutral hydrogen were negative. [17]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
K2-25b | 24.5+5.7 −5.2 M🜨 |
0.0287(12) | 3.48456408+0.0000006 −0.0000005 |
0.428+0.050 −0.049 |
88.16+0.18 −0.21 ° |
3.44(12) R🜨 |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Taurus [1] |
Right ascension | 04h 13m 05.6131s [2] |
Declination | +15° 14′ 52.018″ [2] |
Apparent magnitude (V) | 15.881 [3] |
Characteristics | |
Spectral type | M4.5 V [4] |
Apparent magnitude (J) | 11.303(21) [5] |
Apparent magnitude (H) | 10.732(20) [5] |
Apparent magnitude (K) | 10.444(19) [5] |
Variable type | Planetary transit [4] |
Astrometry | |
Radial velocity (Rv) | 38.64(15) [4] km/s |
Proper motion (μ) |
RA: 122.450(38)
mas/
yr
[2] Dec.: −18.603(26) mas/ yr [2] |
Parallax (π) | 22.3572 ± 0.0308 mas [2] |
Distance | 145.9 ± 0.2
ly (44.73 ± 0.06 pc) |
Details [6] | |
Mass | 0.2634(77) M☉ |
Radius | 0.2932(93) R☉ |
Luminosity | 0.00816(29) L☉ |
Temperature | 3207(58) K |
Metallicity [Fe/H] | 0.15(3) [4] dex |
Rotation | 1.87708(66) d [7] |
Rotational velocity (v sin i) | 7.71(29) [8] km/s |
Age | 650(70) [8] [9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
K2-25 is a young red dwarf star located in the Hyades cluster. There is a single known Neptune-sized planet in a 3.5 day orbit.
Using proper motion measurements in a search for low-luminosity members of the Hyades cluster, William van Altena first identified the star vA 50 (later known as K2-25) as a probable cluster member. [12] Membership in the Hyades cluster was later confirmed. [13] [14] [4]
K2-25 is a red dwarf that is only 26% the mass of the Sun and less than 1% of the luminosity. [6] As a member of the Hyades cluster, it is only 650 million years old as compared to the Sun's 4.5 billion. [8]
There is clear evidence for starspot activity in both the Kepler data and radial velocities as well as the associated activity indicators. [15]
The star has one known planet, K2-25b, with searches of the Kepler space telescope data for transits of additional planets being negative. [4] Analysis of transit-timing variations from the Spitzer Space Telescope as well as the MEarth Project also found no evidence of additional planets. [16]
Brightness measurements of K2-25 taken by the Kepler space telescope during its extended K2 mission led to the discovery of the transiting planet K2-25b. [4] [10]
K2-25b is a Hot Neptune type planet in an eccentric 3.48 day orbit. [15]
Due to its proximity and the activity levels of its host star, K2-25b should be losing some of its atmosphere to space; however, observations of two transits by the Hubble Space Telescope to search for escaping neutral hydrogen were negative. [17]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
K2-25b | 24.5+5.7 −5.2 M🜨 |
0.0287(12) | 3.48456408+0.0000006 −0.0000005 |
0.428+0.050 −0.049 |
88.16+0.18 −0.21 ° |
3.44(12) R🜨 |