 SIMP0136 with the legacy surveys. For a planetary-mass object it is relatively bright (apparent J≈13.4). | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pisces[1] |
| Right ascension | 01h 36m 56.56s[2] |
| Declination | +09° 33′ 47.3″[2] |
| Characteristics | |
| Spectral type | T2.5[3] |
| Apparent magnitude (i) | 20.42±0.06[citation needed] |
| Apparent magnitude (z) | 16.01±0.02[citation needed] |
| Apparent magnitude (J) | 13.455±0.030[citation needed] |
| Apparent magnitude (H) | 12.771±0.032[citation needed] |
| Apparent magnitude (K) | 12.562±0.024[citation needed] |
| Astrometry | |
| Radial velocity (Rv) | 12.3±0.8[4] km/s |
| Proper motion (μ) | RA: +1238.244mas/yr[2] Dec.: −16.156mas/yr[2] |
| Parallax (π) | 163.4478±0.4629 mas[2] |
| Distance | 19.95 ± 0.06 ly (6.12 ± 0.02 pc) |
| Details | |
| Mass | 12.7±1.0[5] MJup |
| Radius | 1.22±0.01[5] RJup |
| Surface gravity (log g) | 4.31±0.03[5] cgs |
| Temperature | 1243[6] K |
| Metallicity | 0.18±0.01[6] |
| Rotation | 2.406±0.008[7] hours |
| Rotational velocity (v sin i) | 52.8+1.1 −1.0[4] km/s |
| Age | 200±50[5] Myr |
| Other designations | |
| 2MASS J01365662+0933473; IPMS J013656.57+093347.3; IBIS J013656.57+093347.3 | |
| Database references | |
| SIMBAD | data |
SIMP J013656.5+093347 (abbreviatedSIMP0136) is aplanetary mass object[5] at 19.9light-years from Earth in the constellationPisces. It belongs to the spectral class T2.5[3] and its position shifts due to itsproper motion of about 1.24arcseconds annually.[2]
In 2017, it was announced that the object's mass may be as low as 12.7Jupiter masses and might be considered arogue planet rather than abrown dwarf as it seems to be a member of the relatively young, 200 million-year-old Carina-Near stellarmoving group.[5][8][9]
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In 2018 astronomers said "Detecting SIMP J01365663+0933473 with theVLA through itsauroral radio emission, also means that we may have a new way of detecting exoplanets, including the elusive rogue ones not orbiting a parent star ... This particular object is exciting because studying its magnetic dynamo mechanisms can give us new insights on how the same type of mechanisms can operate in extrasolar planets – planets beyond our Solar System ... We think these mechanisms can work not only in brown dwarfs, but also in both gas giant and terrestrial planets."[9] During the observation with the VLA only one pulse was detected for SIMP0136. Themagnetic flux of SIMP0136 was estimated to be 3.2kG.[10] In 2025 significantauroral activity was detected on SIMP0136. A re-analysis of the JWST data found that the atmophere showed a temperature inversion at thestratosphere, caused by auroral heating, driven byelectron precipitation. Themethane andcarbon monoxide abundance were found to be inchemical disequelibrium and methane abundance decreases at the temperature inversion.[6] Observations with JWST/NIRSpec andNIRISS were used to find a transition of methane absorption to methane emission at low pressures (highaltitudes). A similar methane emission was found previously only inCWISEP J1935−1546. This transition is explained with auroral heating fromelectron precipitation.[11]
In 2017 the rotational velocity andradial velocity were measured. It was found that SIMP0136 can be seen almostequator-on with aninclination of 80 ±12°.[4]
This planetary-mass object provided the first evidence for periodic variability flux variations among T dwarfs. A team observed this object with the 1.8-mPerkins Telescope Observatory nearFlagstaff, Arizona in 2015. SIMP0136 was observed in 15 nights, spread out over 90 days. The variation has been interpreted as a signature of weather patterns coming in and out of view over the object's 2.4h rotation period. The shape of this lightcurve evolves over timescales of days, which has been interpreted as a sign of evolution of the cloud patterns in its atmosphere.[7] In 2016 a phase shift betweenSpitzer andHubble observations was noticed, which was measured to be 33.4 ±3.9°.[12] In 2023 a team found that SIMP0136 has patchyforsterite (Mg2SiO4) clouds above aniron cloud deck. This patchy cloud layer covers between 69% and 72% of the surface of the object.[13] In 2024 a team re-analysed the 2015 data and detected aphase shift between theJ-band andKs-band of39.9+3.6
−1.1°. The team concluded that the phase shift can be explained with at least two different patchy cloud layers. The J- and Ks-bands both probe different layers of the atmosphere.[14] A study with JWSTNIRSpec andMIRI observed two rotations and were used to study the object in detail. The study found that the variability comes from different parts of the atmosphere, depending on the wavelength. A signal deep within the atmosphere is thought to be connected to patchy iron clouds. Another signal higher up could come from patchy silicate clouds. A third signal comes from high above the clouds and is connected to hot spots, which could represent the aurora or upwelling of hot gas. Some of the light curves produced can only be explained with changing carbon chemistry.[15][16] In a re-analysis the variability was found to be caused by changes of the temperature profile above 10mbar. The effective temperature changed from 1243 K at the coldest to 1248 K at the hottest, which is anbyamplitude of 5 K (or 5°C; 9°F). The spectrum required patchy silicate clouds, which were found not to be the primary cause of variability; the variability was found to be caused by magnetic and thermodynamic mechanisms. The changes of temperature also correlated with a change in abundance ofcarbon dioxide andhydrogen sulfide, which may suggest chemical changes driven by dynamics and storms.[6]
Other planetary-mass objects:
Other T-dwarfs with detected radio emission:
