|
Exoplanet Name : |
K2-257 b |
|
Alternate Name : |
"2MASS J12330683-0157113 b, EPIC 228974324 b, EPIC 228974324.01, WISE J123306.80-015711.7 b" |
|
Status : |
Confirmed |
|
Radius (Rjup / Re): |
0.0740 |
(Rjup) |
0.8295 |
(Rearth) |
|
Mass (Mjup / Me): |
0.0016 |
(Mjup) |
0.5035 |
(Mearth) |
|
Semi Major Axis / Orbital Distance Calculated |
0.0216 |
(AU) |
0.0216 |
(AU Est.) |
|
Eccentricity : |
0.0000 |
|
Orbital Period(Yrs) |
0.0044 |
|
Orbital Period(Observed/Estimated) |
1.61 |
(Days Obs.) |
1.61 |
(Days Est.) |
|
Surface Gravity (G Earth) |
0.7318 |
|
Star Radiation at Atmospheric Boundary: |
126515.1 |
(W/m2) |
|
Measured Temperature (K) |
0.0 |
(K) |
|
Blackbody T 0.1(K) |
841.7 |
(K) |
|
Blackbody T 0.3(K) |
790.5 |
(K) |
|
Blackbody T 0.7(K) |
639.6 |
(K) |
|
Tidally Locked Blackbody T 0.1(K) |
1001.0 |
(K) |
|
Tidally Locked Blackbody T 0.3(K) |
940.0 |
(K) |
|
Size Class: |
Earth-size |
|
Mass Class: |
|
|
Detection Type : |
Primary Transit |
|
Mass Detection : |
|
|
Radius Detection : |
|
|
Habitability by Solar Eq. Astronomical Unit: |
Not habitable |
|
Habitability by Kopparapu: |
Not habitable |
|
Star Name : |
K2-257 |
|
Alternate Name : |
"2MASS J12330683-0157113, EPIC 228974324, WISE J123306.80-015711.7" |
|
Star Distance(LY) : |
211.3 |
|
Stellar Radius(Rsun) : |
0.5 |
(Rsun Measured) |
|
Stellar Mass(Msun) : |
0.5 |
(Msun Measured) |
0.5 |
(Msun Estimated) |
|
Star Age : |
0.0 |
(GY) |
|
Temperature : |
3725 |
(K) |
|
Spectral type : |
M2 |
|
UV portion[%]: |
0.3 |
|
Visible portion[%]: |
13.3 |
|
IR portion[%]: |
86.4 |
|
Metalicity : |
-0.0 |
|
Absolute Magnitude: |
6.4 |
|
Apparent Magnitude: |
10.5 |
|
Right Ascension(RA) |
188.2785 |
|
Declination (DEC) |
-1.9532 |
|
Hubble Space Telescope Guide Star Catalog (GSC) ID |
|
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Discovered by |
|
|
Discovery Paper - Authors |
|
|
Discovery Paper - Title |
|
|
Discovery Paper - Journal |
|
|
Discovery Paper - URL |
|
|
SIMBAD LINK |
https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=K2-257&submit=SIMBAD+search |
|
Open Exoplanet Database Link |
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K2-257 b
K2-257 b
K2-257 b is an exoplanet orbiting the star K2-257, located about 211.3 light-years (64.8 pc) away from Solar System. Its discovery was publicly announced on 2018.
The host star K2-257 has apparent magnitude of 10.5, with absolute magnitude of 6.4. It is 0.5 times more massive and 0.5 times bigger compared with our Sun. The surface temperature is 3725 with its spectral types of M2
In this planetary system, the extrasolar planet K2-257 b orbits around the star K2-257 every 1.6 days with its orbital distance of 0.02 AU ( 3231314.0 km)
(Projected orbit of K2-257 b around its host star K2-257)
The Star K2-257 's habitable zone is located at the following distance
Inner Boundary (the orbital distance at Venus's Equivalent Radiation )
: 0.150 AU ( 22484367.3 km)
Earth Boundary (the orbital distance at Earth's Equivalent Radiation)
: 0.208 AU ( 31079271.5 km)
Outer Boundary (the orbital distance at Mars's Equivalent Radiation)
: 0.317 AU ( 47357931.9 km)
Snow Line (the orbital distance at Snow Line Equivalent Radiation)
: 0.466 AU ( 69689271.4 km)
Radiation at Planetary Boundary of K2-257 b : 126515.12 W/m2
(Habitable zone calculated based on SEAU(Solar Equivalent Astronomical Unit) around the star K2-257)
Kopparapu Recent Venus for Star K2-257 distance : 0.169 AU
Kopparapu Runaway Greenhouse for Earth-sized planet for Star K2-257 distance : 0.214 AU
Kopparapu Runaway Greenhouse for Super-Earth-sized planet for Star K2-257 distance : 0.207 AU
Kopparapu Runaway Greenhouse for Mars-sized planet for Star K2-257 distance : 0.228 AU
Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-257 distance : 0.412 AU
Kopparapu Outer Boundary for Early Mars for Star K2-257 distance : 0.435 AU
(Habitable zone calculated based on Kopparapu et al.(2013) around the star K2-257)
Original Kopparapu Recent Venus for Star K2-257 distance : 0.168 AU
Original Kopparapu Runaway Greenhouse for Star K2-257 distance : 0.222 AU
Original Kopparapu Moist Greenhouse for Star K2-257 distance : 0.222 AU
Original Kopparapu Outer Boundary for Maximum Greenhouse for Star K2-257 distance : 0.419 AU
Original Kopparapu Outer Boundary for Early Mars for Star K2-257 distance : 0.435 AU
(Habitable zone calculated based on Kopparapu et al.(Original) around the star K2-257)
(Position in Stellar Map of star K2-257 and its Exoplanet K2-257 b)
(Zoomed position in Stellar Map of star K2-257 and its Exoplanet K2-257 b (zoom level 3))
(Synthetic Spectrum of star K2-257*)
*Yamashiki YA et al. 2019 ApJ 881 114
MUSCLES Paper I - France et al. 2016 ApJ 820 89
MUSCLES Paper II- Youngblood et al. 2016 ApJ 824 101
MUSCLES Paper III- Loyd et al. 2016 ApJ 824 102
