In addition to known extrasolar planets, there are many planet candidates whose existence is more or less uncertain, or they are now known not to exist. On February 2, 2011, the Kepler Space Observatory Mission team released a list of 1235 (unconfirmed) extrasolar planet candidates.[1] 68 candidates are "Earth-size" (smaller than 1.25 of the radius of Earth); 54 candidates are thought to be in the "Habitiable Zone (HZ);" Six candidates (KOI 326.01, KOI 701.03, KOI 268.01, KOI 1026.01, KOI 854.01, KOI 70.03 - Table 6)[1] in the HZ are less than twice the size of the Earth; one candidate in the HZ is "Earth-size" (namely, KOI 326.01 at 0.85 the radius of Earth). Nonetheless, there are 53 unconfirmed extrasolar planets listed here.
The following planet candidates have been detected indirectly (e.g. by the radial velocity method) but have not yet had sufficient observations to constrain their orbital properties, either because the planet has not yet completed a full orbit during the time of observation, or because the measurements are too sparse. The parameters given in this table are thus preliminary: further observations of these systems may result in significant changes.
Star | Constellation | Right ascension |
Declination | Distance (ly) |
Planet | Mass (MJ) |
Orbital period (d) |
Semimajor axis (AU) |
Orbital eccentricity |
Discovery year |
Ref | Notes |
---|---|---|---|---|---|---|---|---|---|---|---|---|
HD 1461 | Cetus | 00h 18m 42s | −08° 03′ 11″ | 76 | c | ≥0.072 | 454 | 1.165 | 0.74 | 2009 | [2] | The present day (2009) radial velocity method is hard to find Neptune-mass planets at more than 1 AU away from the stars. |
HD 1461 | Cetus | 00h 18m 42s | −08° 03′ 11″ | 76 | d | ≥0.3 | 5000 | 5 | 0.16 | 2009 | [2] | All parameters for this planet are very poorly constrained. |
GD 66 | Auriga | 05h 20m 38s | +30° 48′ 24″ | 170 | b | ≥2.36 | 2080 | 2.75 | ~0 | 2009 | [3][4] | Partial orbit coverage |
Gliese 317 | Pyxis | 08h 40m 59s | −23° 27′ 23″ | 29.9 | c | ≥0.83 | ~2700 | 0.42 | 2007 | [5] | 2-planet solution modifies parameters of (confirmed) planet b. |
There are several known stars for which potential planetary transits have been observed, however they lack enough follow-up information (such as radial velocity measurements) to rule out other hypotheses, such as the presence of a background eclipsing binary star, or a grazing transit of a larger object.
Star | Constellation | Right ascension |
Declination | Distance (ly) |
Planet | Radius (RJ) |
Orbital period (d) |
Discovery year |
Ref | Notes |
---|---|---|---|---|---|---|---|---|---|---|
1SWASP-J115718.66+261906.1 | Leo | 11h 57m 19s | +26° 19′ 06″ | b | 1.32 | 1.226804 | 2007 | [6] | ||
1SWASP-J130322.00+350525.4 | Canes Venatici | 13h 03m 22s | +35° 05′ 25″ | b | 1.06 | 2.674207 | 2007 | [6] | Transit shape suggests this may be a grazing eclipsing binary. | |
1SWASP-J152131.01+213521.3 | Serpens Caput | 15h 21m 31s | +21° 35′ 21″ | b | 1.62 | 1.338018 | 2007 | [6] | ||
1SWASP-J160242.43+290850.1 | Corona Borealis | 16h 02m 42s | +29° 08′ 50″ | b | 1.53 | 1.304693 | 2007 | [6] | Transit shape suggests this may be a grazing eclipsing binary. | |
SWEEPS J175853.29−291233.5 | Sagittarius | 17h 58m 53s | −29° 12′ 34″ | ~22000 | SWEEPS-01 | 1.01 | 1.566 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175853.38–291217.8 | Sagittarius | 17h 58m 53s | −29° 12′ 18″ | ~22000 | SWEEPS-02 | 1.37 | 0.912 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175853.57–291144.1 | Sagittarius | 17h 58m 54s | –29° 11′ 44″ | ~22000 | SWEEPS-03 | 0.87 | 1.279 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175854.60–291128.2 | Sagittarius | 17h 58m 55s | –29° 11′ 28″ | ~22000 | SWEEPS-05 | 1.09 | 2.313 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175857.29–291253.4 | Sagittarius | 17h 58m 57s | –29° 12′ 53″ | ~22000 | SWEEPS-06 | 0.82 | 3.039 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175857.69–291114.5 | Sagittarius | 17h 58m 58s | –29° 11′ 15″ | ~22000 | SWEEPS-07 | 0.90 | 1.747 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175859.24–291328.7 | Sagittarius | 17h 58m 59s | –29° 13′ 29″ | ~22000 | SWEEPS-08 | 0.98 | 0.868 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175859.60–291211.8 | Sagittarius | 17h 59m 00s | –29° 12′ 12″ | ~22000 | SWEEPS-09 | 1.01 | 1.617 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175902.00–291323.7 | Sagittarius | 17h 59m 02s | –29° 13′ 24″ | ~22000 | SWEEPS-10 | 1.24 | 0.424 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175904.44–291317.1 | Sagittarius | 17h 59m 04s | –29° 13′ 17″ | ~22000 | SWEEPS-12 | 0.91 | 2.952 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175905.95–291305.6 | Sagittarius | 17h 59m 06s | –29° 13′ 06″ | ~22000 | SWEEPS-13 | 0.78 | 1.684 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175907.56–291039.8 | Sagittarius | 17h 59m 08s | –29° 10′ 40″ | ~22000 | SWEEPS-14 | 0.93 | 2.965 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175907.64–291023.7 | Sagittarius | 17h 59m 08s | –29° 10′ 24″ | ~22000 | SWEEPS-15 | 1.37 | 0.541 | 2006 | [7] | Distance modulus = 14.1 |
SWEEPS J175908.44–291140.6 | Sagittarius | 17h 59m 08s | –29° 11′ 41″ | ~22000 | SWEEPS-16 | 1.40 | 0.969 | 2006 | [7] | Distance modulus = 14.1 |
CoRoT-102636650 | Monoceros | 06h 42m 18s | -01° 24′ 06″ | - | CoRoT-102636650 b | - | 8.1 | 2007 | [8] | |
CoRoT-102638570 | Monoceros | 06h 42m 21s | -01° 11′ 48″ | - | CoRoT-102638570 b | - | 6.5 | 2007 | [9] | |
OGLE-TR-123 | Carina | 11h 06m 51s | -61° 11′ 10″ | 500 pc | OGLE-TR-123 b | 0.41 | 1.803 | 2010 | [10] | Needs RV measurement |
OGLE-TR-173 | Musca | 13h 14m 56s | -65° 02′ 00″ | 100 pc | OGLE-TR-173 b | 0.43 | 2.605 | 2010 | [11] | Needs RV |
OGLE-TR-61 | Carina | 11h 08m 41s | -61° 07′ 59″ | 250 pc | OGLE-TR-61 b | 0.6 | 4.268 | 2010 | [12] | Needs RV |
OGLE-TR-74 | Carina | 11h 06m 11s | -61° 14′ 53″ | 250 pc | OGLE-TR-74 b | 0.63 | 1.581 | 2010 | [13] | Needs RV |
The following planets have been predicted based on the morphology of dust disks around their stars.
Star | Constellation | Right ascension |
Declination | Distance (ly) |
Planet | Mass (MJ) |
Semimajor axis (AU) |
Orbital eccentricity |
Discovery year |
Ref | Notes |
---|---|---|---|---|---|---|---|---|---|---|---|
Epsilon Eridani | Eridanus | 03h 32m 55s | −09° 27′ 29″ | 10.5 | ~20 | 2008 | [14] | Associated with ~20 AU planetesimal belt. | |||
Epsilon Eridani | Eridanus | 03h 32m 55s | −09° 27′ 29″ | 10.5 | c | ~0.1 | ~40 | ~0.3 | 2002 | [15] | Associated with outer icy debris disk. |
Beta Pictoris | Pictor | 05h 47m 17s | −51° 03′ 59″ | 63.4 | ~0.5 | ~25 | ~0.01 | 2007 | [16] | Associated with ~32 AU planetesimal belt. | |
Beta Pictoris | Pictor | 05h 47m 17s | −51° 03′ 59″ | 63.4 | ~0.1 | ~45 | ~0.01 | 2007 | [16] | Associated with ~52 AU planetesimal belt. |
The following stars have long-term radial velocity trends in addition to any confirmed planets they may have. This may indicate the presence of objects (possibly planetary in nature) in long-period orbits in these systems.
Star | Constellation | Right ascension |
Declination | Distance (ly) |
Velocity trend (m/s per year) |
Ref | Notes |
---|---|---|---|---|---|---|---|
HD 28185 | Eridanus | 04h 26m 26s | −10° 33′ 02″ | 138 | 11.0 | [17] | No trend found by Magellan Planet Search Program.[18] |
Gliese 849 | Aquarius | 22h 09m 40s | −04° 38′ 27″ | 28.7 | −4.6 | [19] |
The following extrasolar planets have been suggested to have variations in the parameters of their transits across the face of their parent stars which may be caused by perturbations from an additional planet. Note that the planet designations listed in this table refer to the (confirmed) transiting planets: it is the additional perturbing planet that is unconfirmed. The discovery year refers to the discovery of the transit variations.
Star | Constellation | Right ascension |
Declination | Distance (ly) |
Transiting Planet |
Discovery year |
Ref | Notes |
---|---|---|---|---|---|---|---|---|
OGLE-TR-111 | Carina | 10h 53m 01s | −61° 24′ 20″ | 5000 | b | 2008 | [20] | Unconfirmed second transiting planet.[21] |
Gliese 436 | Leo | 11h 42m 11s | +26° 42′ 23″ | 33.48 | b | 2008 | [22][23] | Planet candidate Gliese 436 c has been retracted,[24] but alternate solutions are possible.[23] |
WASP-3 | WASP-3 c | 2010 |
This list includes disproven planets: objects which are no longer thought to be planetary, or no longer thought to exist at all, and objects which are detections which are suspected to be non-planetary in nature, for example radial velocity variations which may be caused by stellar variations. This list also contains planets which cannot be confirmed, for example planets detected in microlensing events which have low observational coverage.
Star | Constellation | Right ascension |
Declination | Distance (ly) |
Planet | Discovery year |
Detection method |
Ref | Notes |
---|---|---|---|---|---|---|---|---|---|
WASP-9 | 483 | b | 2008 | Transit | [25] | Discovery retracted: blended eclipsing binary in hierarchical triple.[26] | |||
HD 11964 | Cetus | 01h 57m 09s | −10° 14′ 32″ | 110.8 | d | 2007 | Radial velocity | [27] | Not detected in re-reduced data.[28] Detection possibly an effect of Earth's orbital motion.[27] |
TMR-1 | Taurus | 04h 39m 14s | +25° 53′ 21″ | 460 | C | 1998 | Imaging | [29] | Background star.[30] |
HD 33636 | Orion | 05h 11m 46s | +04° 24′ 13″ | 91.6 | b | 2002 | Radial velocity | [31] | Companion is a red dwarf star in a low-inclination orbit.[32] |
TW Hydrae | Hydra | 11h 01m 52s | −34° 42′ 17″ | 180 | b | 2007 | Radial velocity | [33] | Radial velocity variations caused by stellar spots.[34] |
Gliese 436 | Leo | 11h 42m 11s | +26° 42′ 23″ | 33.48 | c | 2008 | Transit variations | [22] | Retracted by authors.[24] Alternate solutions are still possible.[23] |
QS Virginis | Virgo | 13h 49m 52s | –13° 13′ 38″ | 156.48 | b | 2009 | Eclipsing binary minima | [35] | Subsequent timings showed that patterns were not predicted by planetary models. The best fit model for an orbit would have mass 50 MJup (0.05 M☉) in an eccentric, 14-year orbit.[35] |
1SWASP-J161732.90+242119.0 | Hercules | 16h 17m 33s | +24° 21′ 19″ | b | 2007 | Transits | [6] | No radial velocity variations: planet hypothesis ruled out.[6] | |
HD 150706 | Ursa Minor | 16h 31m 18s | +79° 47′ 23″ | 88.8 | b | 2002 | Radial velocity | [36] | Not detected in independent measurements.[37] |
MACHO-1997-BLG-41 (lens) | Sagittarius | 17h 56m 21s | –28° 47′ 42″ | ~10000 | 1999 | Microlensing | [38] | Detection explained by orbital motion of binary star in lens system.[39] | |
Barnard's Star | Ophiuchus | 17h 57m 48s | +04° 41′ 36″ | 5.98 | various | 1963 | Astrometry | [40] | Failed independent confirmation.[41] Artifact of telescope maintenance procedures.[42] |
PSR B1829−10 | Scutum | 18h 32m 40s | –10° 21′ 33″ | 30000 | 1991 | Pulsar timing | [43] | Error in correcting for Earth's orbital motion.[44] | |
HD 188753 A | Cygnus | 19h 54m 58s | +41° 52′ 18″ | 149 | b | 2005 | Radial velocity | [45] | Planet not detected in follow-up; original data do not support planet hypothesis.[46] |
HD 208487 | Grus | 21h 57m 20s | −37° 45′ 49″ | 144 | c | 2005 | Radial velocity | [47] | Radial velocity variations probably caused by stellar activity.[37] |
HD 219542 B | Pisces | 23h 16m 35s | −01° 35′ 07″ | 178 | b | 2003 | Radial velocity | [48] | Radial velocity variations caused by stellar activity.[49] |
ChaHa8 | Chamaeleon | 11h 07m 48s | -77° 40′ 08″ | 160 pc | b | 2007 | Radial velocity | [50] | New velocity measurements in 2010 bring the mass above the planetary mass limit (30 to 59 MJ) |
Hypothetical types of extrasolar planet include:
|