PEST’s main aim is to find planets.  The easiest to find are hot Jupiters, but ultimately we are looking for other Earths.

Here are a few examples;

LHS 1140b, a super-Earth in the Habitable Zone

An artist’s impression of the rocky exoplanet, LHS 1140b passing in front of its host, a small faint red star. Depicted in blue is the atmosphere the planet may have retained.
Credit: M. Weiss/CfA

LHS 1140b is now among the top candidates in the search for life.  It’s rocky rather than gaseous – we’ve measured both mass and radius.  The amount of heat it receives from its star is of about the same order as Earth, so it may have liquid water.  It’s nearby, only about 40 light years away, and bright enough so telescopes now being built may be able to test its atmosphere for signs of life.  The star is relatively placid.  Many small red stars are active, flaring and blasting any nearby planet with radiation that blows away any atmosphere.


HATS-6b, a warm Saturn

Artist’s impression of HATS-6b transiting its star. Image Credit: ANU


HATS-6b is a bit cooler and a bit less massive than a hot Jupiter and comes with a twist.  It is about the same radius as Jupiter, but with only a third of Jupiter’s mass.  Its year is just 3.3 Earth days long.  At just 0.04 AU from its star, it has a mean temperature of 440 °C.  This seems hot, but this close to a star surely it must be a lot hotter?  Therein lies the twist.  The host star, HATS-6, is a red dwarf, much smaller and cooler than the Sun.  With mass and radius just over half that of our Sun, its surface temperature is only 3770K, compared to the Sun’s 5772K.

This actually is awkward, because we don’t expect large planets to form around small stars.  The planet probably formed further away from the star and then migrated inwards, but current theories don’t explain this well.

OGLE-2013-BLG-0341: An Earth-like planet around one member of a double star system

OGLE-2013-BLG-0341: Image Credit: C Han, Chungbuk National University, Korea.

From this planet you’d see two suns.  One much closer and so brighter than the other.  But both stars are red dwarfs so OGLE-2013-BLG-0341LBb, to give it’s full name, is too cold to support liquid water and therefore life.  Here’s good article on this discovery.


Full list of PEST planet co-discoveries:

108.TOI-3071b0.21 MJ1.37.2 RE15801.312.42.5Hot sub-Saturn
107.TOI-663d<5.2 ME7.11.9 RE2090.513.71.2One of 3 mini-Neptunes around an M star
106.TOI-663c3.7 ME4.72.3 RE2090.513.71.6One of 3 mini-Neptunes around an M star
105.TOI-663b4.5 ME2.62.3 RE2090.513.71.7One of 3 mini-Neptunes around an M star
104.TOI-286c3.7 ME39.41.9 RE- super-Earth possibly water world
103.HD 39688b15.7 ME6.92.7 RE-1.37.3-Rocky planet
102.TOI-871b>3.8 ME14.41.7 RE-0.810.60.5Validated super-Earth
101.TOI-199c>0.3 MJ274NA-0.910.7NANon-transiting warm giant in the HZ inferred from TTV
100.TOI-199b0.2 MJ104.90.8 RJ-0.910.710Warm long period giant with a 6.5hr transit
99.TOI-322b57.2 ME0.83.2 RE7270.912.41Super dense Neptune in the Neptunian desert
98.TOI-733b5.7 ME4.92.0 RE2461.09.40.4Hot planet in the small-planet radius valley
97.TOI-2459b9.1 ME19.13.0 RE-0.710.82Sub-Neptune validated statistically.
96.TOI-672b24.2 ME3.65.3 RE-0.513.68Sub-Saturn validated statistically.
95.AU Mic d1.0 ME12.7NA320.58.8NAEarth size planet validated by TTVs
94.TOI-778b2.8 MJ4.61.4 RJ5281.49.17.4Hot Jupiter around fast spinning star.
93.TOI-4791b2.3 MJ4.31.1 RJ10501.211.66.6Hot Jupiter.
92.TOI-2977b1.7 MJ2.41.2 RJ11600.912.512.7Hot Jupiter.
91.HD 18599b<30 ME4.12.7 RE1300.98.71.0Sub-Saturn a very young nearby star.
90.MOA-2020-BLG-20869 MENANA25,0000.7NANASub-Saturn discovered through microlensing.
89.TOI-2000c75.7 ME9.18.0 RE5641.111.04.3Unusual system. Hot Saturn with an inner planet.
88.TOI-2000b10.3 ME3.12.6 RE5641.111.00.5Mini Neptune inside the orbit of a hot Saturn.
87.TOI-1221b<1.1 MJ91.72.9 RE1.010.50.7Long period Sub-Neptune with evidence of another planet in the system.
86.TOI-411d10.5 ME~463.2 RE2051.18.30.7Sub-Neptune in a multi-planet system with only a single transit seen so far.
85.TOI-411c8.0 ME9.62.7 RE2051.18.30.5Sub-Neptune in a multi-planet system.
84.TOI-411b6.3 ME4.01.7 RE2051.18.30.2Super-Earth in a multi-planet system.
83.GJ 3090b3.3 ME2.92.1 RE730.5211.41.4Mini-Neptune amenable to atmospheric characterisation.
82.HD 73583c9.6 ME18.92.4 RE1030.719.71.1Mini-Neptune around a young bright star.
81.HD 73583b10.0 ME6.42.8 RE1030.719.71.5Mini-Neptune around a young bright star.
80.LHS 1678c<1.4 ME3.691.0 RE650.3512.50.7Earth-sized planet in the Venus zone.
79.LHS 1678b<0.35 ME0.860.7 RE650.3512.50.4Ultra short period planet smaller than Earth.
78.TOI-431d9.9 ME12.53.3 RE1060.89.1-Sub-Neptune in a multi-planet system.
77.TOI-431c2.8 ME4.8- RE1060.89.1-Non-transiting super-Earth in a multi-planet system.
76.TOI-431b3.1 ME0.51.3 RE1060.89.1-Super-Earth in a multi-planet system.
75.Gliese 486b2.8 ME1.51.3 RE260.311.41.3Nearby super Earth ideal for atmospheric characterisation.
74.KMT-2020-BLG-0414Lb1.0 ME--3,0000.322.8-Earth mass planet. Lowest planet/host mass ratio found so far by microlensing.
73.TOI-559b6.0 MJ7.01.1 RE7601.0311.88.3Massive hot Jupiter in an eccentric orbit.
72.TOI-451d8 ME16.44.1 RE4040.9511.01.8One of a system of 3 small planets around a young star.
71.TOI-451c7 ME9.23.1 RE4040.9511.01.0One of a system of 3 small planets around a young star.
70.TOI-451b5 ME1.91.9 RE4040.9511.00.4One of a system of 3 small planets around a young star.
69.TOI-1478b0.9 MJ10.21.1 RJ4990.9510.810.8Warm Jupiter around a near Solar analogue star.
68.TOI-640b0.9 MJ5.01.8 RJ1,1101.510.67.6One of the few highly inflated hot Jupiters with period > 5days.
67.TOI-251b<1.0 MJ4.92.74 RE3251.049.90.8Mini-Neptune around a young star.
66.EPIC 246193072 b0.26 MJ12.50.77 RJ-0.9012.79.4A hot Saturn.
65.TOI-892b0.95 MJ10.61.1 RJ-1.2811.56.2Long period (>10d) Hot Jupiter.
64.TOI-481b1.5 MJ10.31.0 RJ-1.1410.03.8Long period (>10d) Hot Jupiter.
63.TOI-776c6.1 ME15.72.1 RE88.70.5411.51.2Sub-Neptune planet around an M-dwarf.
62.TOI-776b4.7 ME8.251.8 RE88.70.5411.51.0Sub-Neptune planet around an M-dwarf.
61.TOI-561d2.4 ME16.42.3 RE-0.8110.20.7Sub-Neptune planet in one of the oldest planetary systems discovered.
60.TOI-561c6.5 ME10.82.9 RE-0.8110.21.0Sub-Neptune planet in one of the oldest planetary systems discovered.
59.TOI-561b3.2 ME0.441.5 RE-0.8110.20.3Rocky planet in one of the oldest planetary systems discovered.
58.TOI-824b18.5 ME1.392.9 RE2080.6911.21.5Planet at lower edge of the Neptune desert.
57.HATS-37Ab0.10 MJ4.330.6 RJ6880.8412.35.0Planet in the Neptune desert.
56.OGLE-2017-BLG-04060.41 MJN/AN/A17,0000.5626.1-A Saturn around an M-dwarf in the inner Galactic disk
55.TOI-1130c0.97 MJ8.41.5 RJ1900.6811.44.8A Hot Jupiter with inner transiting Neptune. Only the 3rd such system known.
54.TOI-1130b0.17 MJ4.073.7 RE1900.6811.42.4A Neptune with orbit inside that of a Hot Jupiter. Only the 3rd such system known.
53.TOI-849b40.8 ME0.773.5 RE7340.9312.01.2Dense ultra short period Neptune. May be the remnant core of a giant planet.
52.HIP 65Ab3.2 MJ0.982.0 RJ2020.7811.17Ultra short period Jupiter in grazing orbit. Host is member of a binary.
51.TOI-257b0.13 MJ18.390.63 RJ2511.397.61.2Warm sub-Saturn.
50.TOI-564b1.5 MJ1.651.02 RJ6431.0011.29.2Hot Jupiter in a grazing transit.
49.GJ 1252b2.1 ME0.521.2 RE66.50.3812.20.8Ultra-short period small planet around a nearby star.
48.KELT-26b1.4 MJ3.341.94 RJ13601.9310.012.3Hot Jupiter in a highly misaligned orbit.
47.KELT-25b<64 MJ4.401.64 RJ13802.189.75.6Hot Jupiter confirmed with TESS photometry.
46.TOI-132b22.8 ME2.113.43 RE5350.9711.31.5A Neptune-mass but probably rocky planet.
45.TOI-270d5.4 ME11.342.13 RE73.230.3612.62.6My first TESS planets. A sub-Neptune.
44.TOI-270c6.6 ME5.662.42 RE73.230.3612.63.4My first TESS planets. A sub-Neptune.
43.TOI-270b1.9 ME3.361.25 RE73.230.3612.60.9My first TESS planets. A super-Earth around one of the brightest and closest M stars.
42.HATS-58Ab1.0 MJ4.221.10 RJ16001.4611.66.2Hot Jupiter orbiting brighter member of a binary star system.
41.HATS-56b0.60 MJ4.321.69 RJ18801.5711.66.2Highly inflated Hot Jupiter. Possibly another planet in the system.
40.HATS-55b0.92 MJ4.201.25 RJ20401.2013.513.0Typical Hot Jupiter.
39.HATS-54b0.76 MJ2.541.07 RJ25101.1013.96.9Typical Hot Jupiter.
38.HATS-65b0.79 MJ3.111.48 RJ16001.2712.513.7Typical Hot Jupiter.
37.HATS-64b0.93 MJ4.911.67 RJ35501.5612.96.6Typical Hot Jupiter.
36.HATS-63b0.96 MJ3.071.21 RJ20700.9313.913.5Typical Hot Jupiter.
35.HATS-62b0.12 MJ3.281.03 RJ16800.9114.013.2Largest radius super-Neptune found to date
34.HATS-59b0.81 MJ5.421.13 RJ21301.0414.012.5Hot Jupiter with an outer companion on the borderline between massive planet and brown dwarf.
33.KELT-22Ab3.47 MJ1.391.29 RJ7111.0911.114.5Hot Jupiter around one member of a double (and possibly triple) star. On a death spiral into its star. Independent discovery of WASP-173b.
32.HATS-40b1.59 MJ3.261.58 RJ46701.5613.44.7Typical Hot Jupiter. Very shallow transit.
31.HATS-53b0.60 MJ3.851.34 RJ20000.9613.816Typical Hot Jupiter.
30.HATS-52b2.24 MJ1.371.38 RJ20601.1113.718Dense, highly irradiated Hot Jupiter.
29.HATS-50b0.39 MJ3.831.13 RJ23401.1714.011Typical Hot Jupiter with a possible inner planet.
28.HATS-36b2.79 MJ4.181.26 RJ31901.1414.418Typical Hot Jupiter.
27.WASP-167b/KELT-13b< 8 MJ2.021.51 RJ12401.5210.58.2A giant planet in retrograde (i.e. contrary to stellar spin) and mis-aligned orbit.
26.LHS 1140b6.6 ME24.741.43 RE410.1514.25.0Super-Earth in habitable zone. May be best prospect so far to search for life-signature atmospheric gases.
25.KELT-17b1.31 MJ3.081.53 RJ6851.649.39.1Amongst the most massive, hottest, and most rapidly rotating of known planet hosts.
24.KELT-11b0.20 MJ4.741.37 RJ3201.448.02.7Brightest known transiting exoplanet host in the southern hemisphere Shallowest transit depth a planet discovered by a ground-based survey.
23.HATS-34b0.94 MJ2.111.43 RJ17400.9613.822.5Typical Hot Jupiter.
22.HATS-32b0.92 MJ2.811.25 RJ27401.1014.413.7Typical Hot Jupiter.
21.HATS-20b0.27 MJ3.800.78 RJ14800.9113.88.1Dense Saturn-like mass planet.
20.HATS-27b0.53 MJ4.631.50 RJ27401.4212.88.0Among the most inflated of Hot Jupiters discovered. 
19.HATS-12b2.38 MJ3.141.35 RJ32001.4912.85.1Hot Jupiter.  The transit depth is 5 mmag - the 3rd shallowest ground-based planet discovery to date.
18.HATS-11b0.85 MJ3.621.51 RJ29601.0014.112.9Hot Jupiter.  Very metal-poor star.
17.HATS-15b2.17 MJ1.751.11 RJ22500.8714.815.1High-mass hot Jupiter.  High mass planet orbiting unusually close to its star.
16.HATS-17b1.34 MJ16.250.78 RJ11101.1312.45.3Compact warm Jupiter. Longest period transiting planet discovered to date by a ground based survey.
15.KELT-15b0.91 MJ3.331.44 RJ9491.1811.210.0Inflated Jupiter mass planet.
14.KELT-14b1.2 MJ1.711.52 RJ6561.1811.013.1An inflated Jupiter mass planet.  Independent discovery of WASP-122b.
13.KELT-10b0.68 MJ4.171.40 RJ5971.1110.714.2Highly inflated sub-Jupiter mass planet transiting a relatively bright star.
0.39 MJN/AN/A43000.34--Planet around an M-dwarf star, beyond the 'snow line'.
11.HATS-14b1.071 MJ2.771.039 RJ16700.9713.813.1~ Jupiter mass and radius much closer to its host star.
0.543 MJ3.041.212 RJ15500.9613.919.6Inflated hot Jupiter
0.53 MJ3.310.97 RJ16201.1013.18.2Compact hot Jupiter
0.84 MJ1.921.065 RJ20301.0313.35.3Compact hot Jupiter. 
7.HATS-6b0.32 MJ3.330.998 RJ5630.5715.232.3Warm Saturn orbiting a dwarf star.
~2 ME640N/A~30000.13-First Earth-like planet found around a binary star
0.19 MJ957N/A<66000.05--Host is possibly a brown dwarf, but parameters uncertain.
4.HATS-4b1.32 MJ2.521.02 RJ13701.013.12.8A Dense Hot-Jupiter.
1.85 MJ1998N/A57400.022-Host is a brown dwarf
0.68 MJ4018N/A133000.82--Two planet system, beyond 'snow line'
0.11 MJ3011N/A133000.82--Two planet system, beyond 'snow line'

I have included only those planets for which PEST actually made observations (as opposed to instances where I did not contribute observations but was a co-author of the discovery paper).

ME = Earth masses
MJ = Jupiter masses
RE = Earth radii
RJ = Jupiter radii