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K2-21 Overview

  • Star: K2-21
    • Stellar Radius: 0.60 Solar Radius
    • Stellar Effective Temperature: 4043.00 K
    • Planet: K2-21 b
      • Disposition Confirmed
      • Planet Radius 0.164 Jupiter Radius
    • Planet: K2-21 c
      • Disposition Confirmed
      • Planet Radius 0.222 Jupiter Radius

K2-21 Architecture & Discovery Information

Name Orbital Separation Planet Size Method Year Reference Disposition
K2-21
K2-21 b 9.33 d 1.84 R⨁ Transit 2015 Petigura et al. 2015 Confirmed Planet
K2-21 c 15.5 d 2.49 R⨁ Transit 2015 Petigura et al. 2015 Confirmed Planet
K2-21 b K2-21 c
RA
22h41m12.91s
Dec
-14d29m21.57s
Distance
83.6448+0.2665-0.2649
pc
Parallax
11.9265000±0.0376904 mas
Ecliptic Latitude
-5.72499 deg
Ecliptic Longitude
336.36104 deg
Galactic Latitude
-57.17935 deg
Galactic Longitude
48.93602 deg
Total Proper Motion
81.5844334±0.0648486 mas/yr
Proper Motion (RA)
20.7358000±0.0730797 mas/yr
Proper Motion (Dec)
-78.9053000±0.0642412 mas/yr
Photometry
mV 12.851±0.057
mTESS 11.4644±0.0060
mJ 10.251±0.021
mH 9.633±0.022
mKs 9.417±0.020
mKep 12.316
mW1 9.407±0.023
mW2 9.379±0.020
mW3 9.399±0.042
mW4 9.031±0.528
mGaia 12.278500±0.000342
mB 14.138±0.054
mg 13.53±0.02
mi 11.76±0.06
mr 12.32±0.06
Mission
K2: Observed in Campaign 3
Tools
Planetary Systems
ExoFOP Target Overview Page
IRSA Finding Chart
K2 Names
K2 Planets and Candidates
K2 Targets
Stellar Hosts
K2 Time Series
Source TICv8 Gaia DR2 Dressing et al. 2017 Crossfield et al. 2016 Petigura et al. 2015 Kruse et al. 2019 Kruse et al. 2019 Barros et al. 2016 Vanderburg et al. 2016
Teff
(K)
4047.000+132.861-133.442
4213.487+153.000-116.262
4222.061035+88.145287-84.407585
 4006±43 4043±375 --- --- --- 4024
Metallicity
(dex)
--- --- --- --- -0.11±0.13 [Fe/H] --- --- --- ---
Age
(Gyr)
--- --- --- --- >1 --- --- --- ---
M✶
(M⦿)
0.6300000+0.0787268-0.0760954
 --- 0.676023±0.067602 0.523±0.041 0.64±0.11 --- --- --- ---
R✶
(R⦿)
0.6545230+0.0606779-0.0752417
0.57618654+0.03316340-0.03967120
0.646783+0.028803-0.028216
 0.460±0.033 0.60±0.10
0.576 +0.040-0.033
0.576 +0.040-0.033
--- 0.60
Sp. T
--- --- --- --- M0.0 --- --- --- ---
log g
(log10(cm/s2))
4.605560+0.108375-0.123376
 --- --- 4.828±0.050 --- --- --- --- ---
L✶
(log10(L⦿))
-0.9849220+0.0301096-0.0385432
-1.025612+0.002043-0.002052
 --- --- --- --- --- --- ---
γ
(km/s)
--- 4.800261351165759±1.605775761986466 --- --- --- --- --- --- ---
ρ✶
(g/cm3)
3.1675977+1.1400504-1.1006627
 --- --- --- --- --- --- --- ---
Print
Status
Confirmed Planet
Detected By
Transit
Tools
Planetary Systems
Transit Prediction Service
K2 Names
K2 Planets and Candidates
Transit
Source Dressing et al. 2017 Crossfield et al. 2016 Petigura et al. 2015 Kruse et al. 2019 Vanderburg et al. 2016
b
--- ---
0.700+0.150-0.450
 --- 0.54
P
(days)
9.325038+0.000379-0.000403
 9.32389±0.00060
9.32414+0.00059-0.00063
9.32448 +0.00033-0.00034
9.3251498
Rp
(R⨁)
1.84±0.10 1.25±0.11
1.59+0.42-0.44
1.70 +0.14-0.22
1.89
Rp
(RJup)
0.164±0.009 0.112±0.010
0.142+0.037-0.039
0.15 +0.012-0.020
 0.169
Rp/R✶
0.026158+0.000899-0.000720
 0.0246±0.0014
0.0260+0.0012-0.0015
0.0270 +0.0013-0.0031
0.02673
δ
(%)
--- --- --- 0.0809±0.0021 0.0821
T14
(hours)
--- 2.372±0.080
2.305+0.118-0.064
2.52480+0.07920-0.09120
 2.51000
TC
(days)
2456989.422±0.001
(BJD)
2456989.4247±0.0023
(BJD-TDB)
2456989.4239+0.0025-0.0020
(BJD-TDB)
2456980.1007 +0.0017-0.0016
(BJD)
2456980.096
(BJD)
a/R✶
25.37±1.17 ---
23.0+5.9-8.1
25.8 +7.0-3.2
---
Teq
(K)
--- --- 500 --- ---
S
(S⨁)
10.0+2.1-1.7
 10.0±1.6
11.0+10.1-6.0
 --- ---
i
(deg)
88.98+0.50-0.31
 ---
88.3+1.3-1.1
 --- ---
ρ
(g/cm3)
--- ---
2.7+3.7-1.6
 --- ---
a
(au)
0.076+0.002-0.003
 0.0699±0.0018
0.0731+0.0057-0.0067
 --- ---
ω
(deg)
34.4800000+101.8841870-133.7390080
 --- --- --- ---
e
0.100000+0.148654-0.084698
 --- --- --- ---
Print
Status
Confirmed Planet
Detected By
Transit
Tools
Planetary Systems
Transit Prediction Service
K2 Names
K2 Planets and Candidates
Transit
Source Dressing et al. 2017 Crossfield et al. 2016 Petigura et al. 2015 Kruse et al. 2019 Barros et al. 2016 Vanderburg et al. 2016
P
(days)
15.501920+0.000918-0.000928
 15.50116±0.00090
15.50120+0.00093-0.00099
 15.50195±0.00056 15.49412230 15.504102
δ
(%)
--- --- ---
0.1294 +0.0033-0.0035
0.121±0.009 0.120
T14
(hours)
--- 2.333±0.084
2.296+0.137-0.058
2.37840+0.07200-0.10080
2.21000+0.34000-0.34000
 2.27000
TC
(days)
2456988.471±0.002
(BJD)
2456988.4715±0.0018
(BJD-TDB)
2456988.4708+0.0021-0.0017
(BJD-TDB)
2456988.4703 +0.0011-0.0010
(BJD)
2456988.483101
(BJD)
2456988.466
(BJD)
b
--- ---
0.660+0.190-0.400
 --- --- 0.00
Rp
(R⨁)
2.49+0.17-0.19
 1.53±0.14
1.92+0.54-0.52
2.17 +0.18-0.26
--- 2.29
Rp
(RJup)
0.222+0.015-0.017
 0.136±0.012
0.171+0.048-0.046
0.194 +0.016-0.023
 --- 0.204
Rp/R✶
0.035332+0.001742-0.002190
 0.0302±0.0018
0.0315+0.0022-0.0017
0.0345 +0.0016-0.0036
--- 0.03099
a/R✶
35.50±1.63 ---
41.0+8.4-16.8
45.6 +12.7-6.0
--- ---
Teq
(K)
--- --- 420 --- --- ---
S
(S⨁)
5.1+1.1-0.9
 5.09±0.81
5.60+5.10-3.10
 --- --- ---
i
(deg)
88.85+0.40-0.15
 ---
89.08+0.63-0.75
 --- --- ---
ρ
(g/cm3)
--- ---
5.40+5.40-3.50
 --- --- ---
a
(au)
0.107+0.003-0.004
 0.09800±0.00260
0.1026+0.0079-0.0094
 --- --- ---
ω
(deg)
59.9600000+75.6751870-120.5778310
 --- --- --- --- ---
e
0.210000+0.206770-0.173719
 --- --- --- --- ---
Print
Known Objects
2 Confirmed Planets
1 K2 Targets
1 2MASS Point Source Catalog
Data Files
1 K2 Time Series
2 Associated Literature Data
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