SIMP J013656.5+093347 Is Likely a Planetary-mass Object in the Carina-Near Moving Group

Gagné, Jonathan; Faherty, Jacqueline K.; Burgasser, Adam J.; Artigau, Étienne; Bouchard, Sandie; Li, Albert; Lafrenière, David; Doyon, René; Gagliuffi, Daniella Bardalez

doi:10.3847/2041-8213/aa70e2

Cited by 79 publications

(80 citation statements)

References 58 publications

(99 reference statements)

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“…There is also tentative evidence that the low-gravity T dwarfs exhibit higher variability amplitudes compared to field objects. Gagné et al (2017) find that the highly variable object SIMP0136 is a likely member of the ∼ 200 Myr Carina-Near moving group. Gagné et al (2018a) confirm the variable object 2M1324 as a member of the AB Doradus moving group and estimate a mass of 11 − 12 M Jup .…”

Section: Introductionmentioning

confidence: 81%

A Search for Variability in Exoplanet Analogues and Low-Gravity Brown Dwarfs

Vos

Biller

Bonavita

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We report the results of a J-band survey for photometric variability in a sample of young, low-gravity objects using the New Technology Telescope (NTT) and the United Kingdom InfraRed Telescope (UKIRT). Surface gravity is a key parameter in the atmospheric properties of brown dwarfs and this is the first large survey that aims to test the gravity dependence of variability properties. We do a full analysis of the spectral signatures of youth and assess the group membership probability of each target using membership tools from the literature. This results in a 30 object sample of young low-gravity brown dwarfs. Since we are lacking in objects with spectral types later than L9, we focus our statistical analysis on the L0-L8.5 objects. We find that the variability occurrence rate of L0-L8.5 low-gravity brown dwarfs in this survey is 30 +16 −8 %. We reanalyse the results of Radigan (2014) and find that the field dwarfs with spectral types L0-L8.5 have a variability occurrence rate of 11 +13 −4 %. We determine a probability of 98% that the samples are drawn from different distributions. This is the first quantitative indication that the low-gravity objects are more likely to be variable than the field dwarf population. Furthermore, we present follow-up J S and K S observations of the young, planetary-mass variable object PSO 318.5-22 over three consecutive nights. We find no evidence of phase shifts between the J S and K S bands and find higher J S amplitudes. We use the J S lightcurves to measure a rotational period of 8.45 ± 0.05 hr for PSO 318.5-22.

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Section: Introductionmentioning

confidence: 81%

A Search for Variability in Exoplanet Analogues and Low-Gravity Brown Dwarfs

Vos

Biller

Bonavita

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…Because substellar objects cool down as they age (Burrows et al 2001), one of the main strategies to identify planetary-mass objects has been to focus on young associations with a well-known age, which provides a way to estimate masses based on observed temperatures and evolutionary models. The nearest young associations have a few members within 10 pc of the Sun (e.g., Gagné et al 2017), making them compelling laboratories to identify the lowest-mass objects in magnitude-limited surveys. However, their proximity means that their members are spread on large areas of the sky, making it hard to identify new members at a high confidence without measuring their full 6-dimensional kinematics.…”

Section: Introductionmentioning

confidence: 99%

“…This tool served as the base to start the BASS-Ultracool survey (J. Gagné et al, in preparation; see also Gagné et al 2015aGagné et al , 2017and Bardalez Gagliuffi et al 2018), an all-sky search for isolated planetary-mass objects in 2MASS (Skrutskie et al 2006) and AllWISE (Wright et al 2010;Kirkpatrick et al 2014), with a particular focus on objects in the T spectral class where clouds migrate to depths below their photosphere and methane becomes apparent in their spectra (Burgasser et al 2006). As part of this work, the known substellar object 2MASS J13243553+6358281 (2MASS J1324+6358 hereafter) was identified as a candidate member of the 149 +51 −19 Myr-old (Bell et al 2015) AB Doradus moving Relative spectral energy distribution of 2MASS J1324+6358 compared with two field T2 dwarfs.…”

Section: Introductionmentioning

confidence: 99%

2MASS J13243553+6358281 Is an Early T-type Planetary-mass Object in the AB Doradus Moving Group

Gagné

Allers

Theissen

et al. 2018

ApJL

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We present new radial velocity and trigonometric parallax measurements indicating that the unusually red and photometrically variable T2 dwarf 2MASS J13243553+6358281 is a member of the young (∼ 150 Myr) AB Doradus moving group based on its space velocity. We estimate its model-dependent mass in the range 11-12 M Jup at the age of the AB Doradus moving group, and its trigonometric parallax distance of 12.7 ± 1.5 pc makes it one of the nearest known isolated planetary-mass objects. The unusually red continuum of 2MASS J13243553+6358281 in the near-infrared was previously suspected to be caused by an unresolved L+T brown dwarf binary, although it was never observed with high-spatial resolution imaging. This new evidence of youth suggests that a low surface gravity may be sufficient to explain this peculiar feature. Using the new parallax we find that its absolute J-band magnitude is ∼ 0.4 mag fainter than equivalent-type field brown dwarfs, suggesting that the binary hypothesis is unlikely. The fundamental properties of 2MASS J13243553+6358281 follow the spectral type sequence of other known high-likelihood members of the AB Doradus moving group. The effective temperature of 2MASS J13243553+6358281 provides the first precise constraint on the L/T transition at a known young age, and indicates that it happens at a temperature of ∼ 1150 K at ∼ 150 Myr, compared to ∼ 1250 K for field brown dwarfs.

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“…To better understand the role that gravity plays in the L/T transition, a large sample of benchmarks spanning a wide range in surface gravities (or equivalently ages) is essential. Since the most recent large photometric analyses (e.g., Faherty et al 2016;Liu et al 2016), the census of planetary and substellar benchmarks has been expanded, as (1) new young moving group members and companions to stars or white dwarfs have been discovered, whose ages can be determined from their host associations or primary stars (e.g., COCONUTS-1 in this work; Bowler et al 2017;Deacon et al 2017;Gagné et al 2017Gagné et al , 2018Gauza et al 2019), and (2) more substellar binaries and companions have measured dynamical masses thanks to ongoing astrometric monitoring programs (e.g., Dupuy & Liu 2017;Dupuy et al 2019). In addition, the current census of benchmarks can now have very precise absolute magnitudes and physical properties (e.g., bolometric luminosities and effective temperatures), as a result of the high-precision parallaxes from Gaia DR2 (Gaia Collaboration et al 2016).…”

Section: The Surface-gravity Dependence Of the L/t Transitionmentioning

confidence: 99%

COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-gravity T4 Benchmark around an Old White Dwarf and a Re-examination of the Surface-gravity Dependence of the L/T Transition

Zhang

Liu

Hermes

et al. 2020

ApJ

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We present the first discovery from the COol Companions ON Ultrawide orbiTS (COCONUTS) program, a large-scale survey for wide-orbit planetary and substellar companions. We have discovered a co-moving system COCONUTS-1, composed of a hydrogen-dominated white dwarf (PSO J058.9855 + 45.4184; d = 31.5 pc) and a T4 companion (PSO J058.9869 + 45.4296) at a 40.6 (1280 au) projected separation. We derive physical properties for COCONUTS-1B from (1) its near-infrared spectrum using cloudless Sonora atmospheric models, and (2) its luminosity and the white dwarf's age (7.3 +2.8 −1.6 Gyr) using Sonora evolutionary models. The two methods give consistent temperatures and radii, but atmospheric models infer a lower surface gravity and therefore an unphysically young age. Assuming evolutionary model parameters (T eff = 1255 +6 −8 K, log g = 5.44 +0.02 −0.03 dex, R = 0.789 +0.011 −0.005 R Jup ), we find cloudless model atmospheres have brighter Y -and J-band fluxes than the data, suggesting condensate clouds have not fully dispersed around 1300 K. The W2 flux (4.6 µm) of COCONUTS-1B is fainter than models, suggesting non-equilibrium mixing of CO. To investigate the gravity dependence of the L/T transition, we compile all 60 known L6−T6 benchmarks and derive a homogeneous set of temperatures, surface gravities, and masses. As is wellknown, young, low-gravity late-L dwarfs have significantly fainter, redder near-infrared photometry and ≈ 200 − 300 K cooler temperatures than old, high-gravity objects. Our sample now reveals such gravity dependence becomes weaker for T dwarfs, with young objects having comparable near-infrared photometry and ≈ 100 K cooler temperatures compared to old objects. Finally, we find that young objects have a larger amplitude J-band brightening than old objects, and also brighten at H band as they cross the L/T transition.

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SIMP J013656.5+093347 Is Likely a Planetary-mass Object in the Carina-Near Moving Group

Cited by 79 publications

References 58 publications

A Search for Variability in Exoplanet Analogues and Low-Gravity Brown Dwarfs

A Search for Variability in Exoplanet Analogues and Low-Gravity Brown Dwarfs

2MASS J13243553+6358281 Is an Early T-type Planetary-mass Object in the AB Doradus Moving Group

COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-gravity T4 Benchmark around an Old White Dwarf and a Re-examination of the Surface-gravity Dependence of the L/T Transition

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