Discoveries – Perth Exoplanet Survey Telescope

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:

No.	Name	Mass_p	P /_days	Rad_p	Dist /_lyrs	Mass_{s /M_sun}	V_mag	Depth /_mmag	Remarks
108.	TOI-3071b	0.21 M_J	1.3	7.2 R_E	1580	1.3	12.4	2.5	Hot sub-Saturn
107.	TOI-663d	<5.2 M_E	7.1	1.9 R_E	209	0.5	13.7	1.2	One of 3 mini-Neptunes around an M star
106.	TOI-663c	3.7 M_E	4.7	2.3 R_E	209	0.5	13.7	1.6	One of 3 mini-Neptunes around an M star
105.	TOI-663b	4.5 M_E	2.6	2.3 R_E	209	0.5	13.7	1.7	One of 3 mini-Neptunes around an M star
104.	TOI-286c	3.7 M_E	39.4	1.9 R_E	-	0.8	9.9	0.6	A super-Earth possibly water world
103.	HD 39688b	15.7 M_E	6.9	2.7 R_E	-	1.3	7.3	-	Rocky planet
102.	TOI-871b	>3.8 M_E	14.4	1.7 R_E	-	0.8	10.6	0.5	Validated super-Earth
101.	TOI-199c	>0.3 M_J	274	NA	-	0.9	10.7	NA	Non-transiting warm giant in the HZ inferred from TTV
100.	TOI-199b	0.2 M_J	104.9	0.8 R_J	-	0.9	10.7	10	Warm long period giant with a 6.5hr transit
99.	TOI-322b	57.2 M_E	0.8	3.2 R_E	727	0.9	12.4	1	Super dense Neptune in the Neptunian desert
98.	TOI-733b	5.7 M_E	4.9	2.0 R_E	246	1.0	9.4	0.4	Hot planet in the small-planet radius valley
97.	TOI-2459b	9.1 M_E	19.1	3.0 R_E	-	0.7	10.8	2	Sub-Neptune validated statistically.
96.	TOI-672b	24.2 M_E	3.6	5.3 R_E	-	0.5	13.6	8	Sub-Saturn validated statistically.
95.	AU Mic d	1.0 M_E	12.7	NA	32	0.5	8.8	NA	Earth size planet validated by TTVs
94.	TOI-778b	2.8 M_J	4.6	1.4 R_J	528	1.4	9.1	7.4	Hot Jupiter around fast spinning star.
93.	TOI-4791b	2.3 M_J	4.3	1.1 R_J	1050	1.2	11.6	6.6	Hot Jupiter.
92.	TOI-2977b	1.7 M_J	2.4	1.2 R_J	1160	0.9	12.5	12.7	Hot Jupiter.
91.	HD 18599b	<30 M_E	4.1	2.7 R_E	130	0.9	8.7	1.0	Sub-Saturn a very young nearby star.
90.	MOA-2020-BLG-208	69 M_E	NA	NA	25,000	0.7	NA	NA	Sub-Saturn discovered through microlensing.
89.	TOI-2000c	75.7 M_E	9.1	8.0 R_E	564	1.1	11.0	4.3	Unusual system. Hot Saturn with an inner planet.
88.	TOI-2000b	10.3 M_E	3.1	2.6 R_E	564	1.1	11.0	0.5	Mini Neptune inside the orbit of a hot Saturn.
87.	TOI-1221b	<1.1 M_J	91.7	2.9 R_E		1.0	10.5	0.7	Long period Sub-Neptune with evidence of another planet in the system.
86.	TOI-411d	10.5 M_E	~46	3.2 R_E	205	1.1	8.3	0.7	Sub-Neptune in a multi-planet system with only a single transit seen so far.
85.	TOI-411c	8.0 M_E	9.6	2.7 R_E	205	1.1	8.3	0.5	Sub-Neptune in a multi-planet system.
84.	TOI-411b	6.3 M_E	4.0	1.7 R_E	205	1.1	8.3	0.2	Super-Earth in a multi-planet system.
83.	GJ 3090b	3.3 M_E	2.9	2.1 R_E	73	0.52	11.4	1.4	Mini-Neptune amenable to atmospheric characterisation.
82.	HD 73583c	9.6 M_E	18.9	2.4 R_E	103	0.71	9.7	1.1	Mini-Neptune around a young bright star.
81.	HD 73583b	10.0 M_E	6.4	2.8 R_E	103	0.71	9.7	1.5	Mini-Neptune around a young bright star.
80.	LHS 1678c	<1.4 M_E	3.69	1.0 R_E	65	0.35	12.5	0.7	Earth-sized planet in the Venus zone.
79.	LHS 1678b	<0.35 M_E	0.86	0.7 R_E	65	0.35	12.5	0.4	Ultra short period planet smaller than Earth.
78.	TOI-431d	9.9 M_E	12.5	3.3 R_E	106	0.8	9.1	-	Sub-Neptune in a multi-planet system.
77.	TOI-431c	2.8 M_E	4.8	- R_E	106	0.8	9.1	-	Non-transiting super-Earth in a multi-planet system.
76.	TOI-431b	3.1 M_E	0.5	1.3 R_E	106	0.8	9.1	-	Super-Earth in a multi-planet system.
75.	Gliese 486b	2.8 M_E	1.5	1.3 R_E	26	0.3	11.4	1.3	Nearby super Earth ideal for atmospheric characterisation.
74.	KMT-2020-BLG-0414Lb	1.0 M_E	-	-	3,000	0.3	22.8	-	Earth mass planet. Lowest planet/host mass ratio found so far by microlensing.
73.	TOI-559b	6.0 M_J	7.0	1.1 R_E	760	1.03	11.8	8.3	Massive hot Jupiter in an eccentric orbit.
72.	TOI-451d	8 M_E	16.4	4.1 R_E	404	0.95	11.0	1.8	One of a system of 3 small planets around a young star.
71.	TOI-451c	7 M_E	9.2	3.1 R_E	404	0.95	11.0	1.0	One of a system of 3 small planets around a young star.
70.	TOI-451b	5 M_E	1.9	1.9 R_E	404	0.95	11.0	0.4	One of a system of 3 small planets around a young star.
69.	TOI-1478b	0.9 M_J	10.2	1.1 R_J	499	0.95	10.8	10.8	Warm Jupiter around a near Solar analogue star.
68.	TOI-640b	0.9 M_J	5.0	1.8 R_J	1,110	1.5	10.6	7.6	One of the few highly inflated hot Jupiters with period > 5days.
67.	TOI-251b	<1.0 M_J	4.9	2.74 R_E	325	1.04	9.9	0.8	Mini-Neptune around a young star.
66.	EPIC 246193072 b	0.26 M_J	12.5	0.77 R_J	-	0.90	12.7	9.4	A hot Saturn.
65.	TOI-892b	0.95 M_J	10.6	1.1 R_J	-	1.28	11.5	6.2	Long period (>10d) Hot Jupiter.
64.	TOI-481b	1.5 M_J	10.3	1.0 R_J	-	1.14	10.0	3.8	Long period (>10d) Hot Jupiter.
63.	TOI-776c	6.1 M_E	15.7	2.1 R_E	88.7	0.54	11.5	1.2	Sub-Neptune planet around an M-dwarf.
62.	TOI-776b	4.7 M_E	8.25	1.8 R_E	88.7	0.54	11.5	1.0	Sub-Neptune planet around an M-dwarf.
61.	TOI-561d	2.4 M_E	16.4	2.3 R_E	-	0.81	10.2	0.7	Sub-Neptune planet in one of the oldest planetary systems discovered.
60.	TOI-561c	6.5 M_E	10.8	2.9 R_E	-	0.81	10.2	1.0	Sub-Neptune planet in one of the oldest planetary systems discovered.
59.	TOI-561b	3.2 M_E	0.44	1.5 R_E	-	0.81	10.2	0.3	Rocky planet in one of the oldest planetary systems discovered.
58.	TOI-824b	18.5 M_E	1.39	2.9 R_E	208	0.69	11.2	1.5	Planet at lower edge of the Neptune desert.
57.	HATS-37Ab	0.10 M_J	4.33	0.6 R_J	688	0.84	12.3	5.0	Planet in the Neptune desert.
56.	OGLE-2017-BLG-0406	0.41 M_J	N/A	N/A	17,000	0.56	26.1	-	A Saturn around an M-dwarf in the inner Galactic disk
55.	TOI-1130c	0.97 M_J	8.4	1.5 R_J	190	0.68	11.4	4.8	A Hot Jupiter with inner transiting Neptune. Only the 3rd such system known.
54.	TOI-1130b	0.17 M_J	4.07	3.7 R_E	190	0.68	11.4	2.4	A Neptune with orbit inside that of a Hot Jupiter. Only the 3rd such system known.
53.	TOI-849b	40.8 M_E	0.77	3.5 R_E	734	0.93	12.0	1.2	Dense ultra short period Neptune. May be the remnant core of a giant planet.
52.	HIP 65Ab	3.2 M_J	0.98	2.0 R_J	202	0.78	11.1	7	Ultra short period Jupiter in grazing orbit. Host is member of a binary.
51.	TOI-257b	0.13 M_J	18.39	0.63 R_J	251	1.39	7.6	1.2	Warm sub-Saturn.
50.	TOI-564b	1.5 M_J	1.65	1.02 R_J	643	1.00	11.2	9.2	Hot Jupiter in a grazing transit.
49.	GJ 1252b	2.1 M_E	0.52	1.2 R_E	66.5	0.38	12.2	0.8	Ultra-short period small planet around a nearby star.
48.	KELT-26b	1.4 M_J	3.34	1.94 R_J	1360	1.93	10.0	12.3	Hot Jupiter in a highly misaligned orbit.
47.	KELT-25b	<64 M_J	4.40	1.64 R_J	1380	2.18	9.7	5.6	Hot Jupiter confirmed with TESS photometry.
46.	TOI-132b	22.8 M_E	2.11	3.43 R_E	535	0.97	11.3	1.5	A Neptune-mass but probably rocky planet.
45.	TOI-270d	5.4 M_E	11.34	2.13 R_E	73.23	0.36	12.6	2.6	My first TESS planets. A sub-Neptune.
44.	TOI-270c	6.6 M_E	5.66	2.42 R_E	73.23	0.36	12.6	3.4	My first TESS planets. A sub-Neptune.
43.	TOI-270b	1.9 M_E	3.36	1.25 R_E	73.23	0.36	12.6	0.9	My first TESS planets. A super-Earth around one of the brightest and closest M stars.
42.	HATS-58Ab	1.0 M_J	4.22	1.10 R_J	1600	1.46	11.6	6.2	Hot Jupiter orbiting brighter member of a binary star system.
41.	HATS-56b	0.60 M_J	4.32	1.69 R_J	1880	1.57	11.6	6.2	Highly inflated Hot Jupiter. Possibly another planet in the system.
40.	HATS-55b	0.92 M_J	4.20	1.25 R_J	2040	1.20	13.5	13.0	Typical Hot Jupiter.
39.	HATS-54b	0.76 M_J	2.54	1.07 R_J	2510	1.10	13.9	6.9	Typical Hot Jupiter.
38.	HATS-65b	0.79 M_J	3.11	1.48 R_J	1600	1.27	12.5	13.7	Typical Hot Jupiter.
37.	HATS-64b	0.93 M_J	4.91	1.67 R_J	3550	1.56	12.9	6.6	Typical Hot Jupiter.
36.	HATS-63b	0.96 M_J	3.07	1.21 R_J	2070	0.93	13.9	13.5	Typical Hot Jupiter.
35.	HATS-62b	0.12 M_J	3.28	1.03 R_J	1680	0.91	14.0	13.2	Largest radius super-Neptune found to date
34.	HATS-59b	0.81 M_J	5.42	1.13 R_J	2130	1.04	14.0	12.5	Hot Jupiter with an outer companion on the borderline between massive planet and brown dwarf.
33.	KELT-22Ab	3.47 M_J	1.39	1.29 R_J	711	1.09	11.1	14.5	Hot 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-40b	1.59 M_J	3.26	1.58 R_J	4670	1.56	13.4	4.7	Typical Hot Jupiter. Very shallow transit.
31.	HATS-53b	0.60 M_J	3.85	1.34 R_J	2000	0.96	13.8	16	Typical Hot Jupiter.
30.	HATS-52b	2.24 M_J	1.37	1.38 R_J	2060	1.11	13.7	18	Dense, highly irradiated Hot Jupiter.
29.	HATS-50b	0.39 M_J	3.83	1.13 R_J	2340	1.17	14.0	11	Typical Hot Jupiter with a possible inner planet.
28.	HATS-36b	2.79 M_J	4.18	1.26 R_J	3190	1.14	14.4	18	Typical Hot Jupiter.
27.	WASP-167b/KELT-13b	< 8 M_J	2.02	1.51 R_J	1240	1.52	10.5	8.2	A giant planet in retrograde (i.e. contrary to stellar spin) and mis-aligned orbit.
26.	LHS 1140b	6.6 M_E	24.74	1.43 R_E	41	0.15	14.2	5.0	Super-Earth in habitable zone. May be best prospect so far to search for life-signature atmospheric gases.
25.	KELT-17b	1.31 M_J	3.08	1.53 R_J	685	1.64	9.3	9.1	Amongst the most massive, hottest, and most rapidly rotating of known planet hosts.
24.	KELT-11b	0.20 M_J	4.74	1.37 R_J	320	1.44	8.0	2.7	Brightest known transiting exoplanet host in the southern hemisphere Shallowest transit depth a planet discovered by a ground-based survey.
23.	HATS-34b	0.94 M_J	2.11	1.43 R_J	1740	0.96	13.8	22.5	Typical Hot Jupiter.
22.	HATS-32b	0.92 M_J	2.81	1.25 R_J	2740	1.10	14.4	13.7	Typical Hot Jupiter.
21.	HATS-20b	0.27 M_J	3.80	0.78 R_J	1480	0.91	13.8	8.1	Dense Saturn-like mass planet.
20.	HATS-27b	0.53 M_J	4.63	1.50 R_J	2740	1.42	12.8	8.0	Among the most inflated of Hot Jupiters discovered.
19.	HATS-12b	2.38 M_J	3.14	1.35 R_J	3200	1.49	12.8	5.1	Hot Jupiter. The transit depth is 5 mmag - the 3rd shallowest ground-based planet discovery to date.
18.	HATS-11b	0.85 M_J	3.62	1.51 R_J	2960	1.00	14.1	12.9	Hot Jupiter. Very metal-poor star.
17.	HATS-15b	2.17 M_J	1.75	1.11 R_J	2250	0.87	14.8	15.1	High-mass hot Jupiter. High mass planet orbiting unusually close to its star.
16.	HATS-17b	1.34 M_J	16.25	0.78 R_J	1110	1.13	12.4	5.3	Compact warm Jupiter. Longest period transiting planet discovered to date by a ground based survey.
15.	KELT-15b	0.91 M_J	3.33	1.44 R_J	949	1.18	11.2	10.0	Inflated Jupiter mass planet.
14.	KELT-14b	1.2 M_J	1.71	1.52 R_J	656	1.18	11.0	13.1	An inflated Jupiter mass planet. Independent discovery of WASP-122b.
13.	KELT-10b	0.68 M_J	4.17	1.40 R_J	597	1.11	10.7	14.2	Highly inflated sub-Jupiter mass planet transiting a relatively bright star.
12.	OGLE-2012- BLG-0563Lb	0.39 M_J	N/A	N/A	4300	0.34	-	-	Planet around an M-dwarf star, beyond the 'snow line'.
11.	HATS-14b	1.071 M_J	2.77	1.039 R_J	1670	0.97	13.8	13.1	~ Jupiter mass and radius much closer to its host star.
10.	HATS-13b	0.543 M_J	3.04	1.212 R_J	1550	0.96	13.9	19.6	Inflated hot Jupiter
9.	HATS-10b	0.53 M_J	3.31	0.97 R_J	1620	1.10	13.1	8.2	Compact hot Jupiter
8.	HATS-9b	0.84 M_J	1.92	1.065 R_J	2030	1.03	13.3	5.3	Compact hot Jupiter.
7.	HATS-6b	0.32 M_J	3.33	0.998 R_J	563	0.57	15.2	32.3	Warm Saturn orbiting a dwarf star.
6.	OGLE-2013 -BLG-0341LBb	~2 M_E	640	N/A	~3000	0.13		-	First Earth-like planet found around a binary star system.
5.	MOA-2013- BLG-220Lb	0.19 M_J	957	N/A	<6600	0.05	-	-	Host is possibly a brown dwarf, but parameters uncertain.
4.	HATS-4b	1.32 M_J	2.52	1.02 R_J	1370	1.0	13.	12.8	A Dense Hot-Jupiter.
3.	OGLE-2012- BLG-0358Lb	1.85 M_J	1998	N/A	5740	0.022		-	Host is a brown dwarf
2.	OGLE-2012- BLG-0026Lc	0.68 M_J	4018	N/A	13300	0.82	-	-	Two planet system, beyond 'snow line'
1.	OGLE-2012- BLG-0026Lb	0.11 M_J	3011	N/A	13300	0.82	-	-	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).

M_E = Earth masses
M_J = Jupiter masses
R_E = Earth radii
R_J = Jupiter radii