Implications of the discovery of AF Lep b

Gratton, R.; Bonavita, M.; Mesa, D.; Zurlo, A.; Marino, S.; Desidera, S.; D’Orazi, V.; Rigliaco, E.; Squicciarini, V.; Nogueira, P. H.

doi:10.1051/0004-6361/202348012

Cited by 3 publications

(1 citation statement)

References 109 publications

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“…It is also vital for understanding the differences between free-floating planetary-mass objects and directly imaged exoplanets. Directly imaged exoplanets occupy a unique color-magnitude sequence (e.g., Gratton et al 2024), and the discovery of extremely red, faint objects such as CWISE J0506+0738 (a strong candidate member of the β Pictoris moving group, or BPMG; Schneider et al 2023a), serves to narrow the color-magnitude gap.…”

Section: Introductionmentioning

confidence: 99%

Discovery of the Remarkably Red L/T Transition Object VHS J183135.58-551355.9

Bickle,

Schneider,

Gagné

et al. 2024

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We present the discovery of VHS J183135.58−551355.9 (hereafter VHS J1831−5513), an L/T transition dwarf identified as a result of its unusually red near-infrared colors (J − K S = 3.633 ± 0.277 mag; J − W2 = 6.249 ± 0.245 mag) from the VISTA Hemisphere Survey and CatWISE2020 surveys. We obtain low-resolution near-infrared spectroscopy of VHS J1831−5513 using the Magellan Folded port InfraRed Echellette spectrograph to confirm its extremely red nature and assess features sensitive to surface gravity (i.e., youth). Its near-infrared spectrum shows multiple CH4 absorption features, indicating an exceptionally low effective temperature for its spectral type. Based on proper-motion measurements from CatWISE2020 and a photometric distance derived from its K s -band magnitude, we find that VHS J1831−5513 is a likely (∼85% probability) kinematic member of the β Pictoris moving group. Future radial velocity and trigonometric parallax measurements will clarify such membership. Follow-up mid-infrared or higher-resolution near-infrared spectroscopy of this object will allow for further investigation as to the cause(s) of its redness, such as youth, clouds, and viewing geometry.

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Section: Introductionmentioning

confidence: 99%

Discovery of the Remarkably Red L/T Transition Object VHS J183135.58-551355.9

Bickle,

Schneider,

Gagné

et al. 2024

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Deep imaging of three accelerating stars using SHARK-NIR and LMIRCam at LBT

Mesa,

Gratton,

D’Orazi

et al. 2024

Monthly Notices of the Royal Astronomical Society

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The combination of detection techniques enhances our ability to identify companions orbiting nearby stars. We employed high-contrast imaging to constrain mass and separation of possible companions responsible for the significant proper motion anomalies of the nearby stars HIP 11696, HIP 47110 and HIP 36277. These targets were observed using the LBT’s high-contrast camera, SHARK-NIR, in H-band using a Gaussian coronagraph, and with the LMIRCam instrument in the L’-band and using a vAPP coronagraph. Both observations were conducted simultaneously. Additionally, constraints at short separations from the host star are derived analyzing the renormalized unit weight error (RUWE) values from the Gaia catalogue. We find that the companion responsible for the anomaly signal of HIP 11696 is likely positioned at a distance from 2.5 to 28 astronomical units from its host. Its mass is estimated to be between 4 and 16 Jupiter masses, with the greater mass possible only at the upper end of the separation range. Similar limits were obtained for HIP 47110 where the companion should reside between 3 and 30 au with a mass between 3 and 10 MJup. For HIP 36277, we identified a faint stellar companion at large separation, though it might be substellar depending on the assumed age for the star. Considering the older age, this object accounts for the absolute value of the PMa vector but not for its direction. Additionally, we found a substellar candidate companion at a closer separation that could explain the PMa signal, considering a younger age for the system.

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VLTI/GRAVITY Observations of AF Lep b: Preference for Circular Orbits, Cloudy Atmospheres, and a Moderately Enhanced Metallicity

Balmer,

Franson,

Chomez

et al. 2024

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Direct imaging observations are biased toward wide-separation, massive companions that have degenerate formation histories. Although the majority of exoplanets are expected to form via core accretion, most directly imaged exoplanets have not been convincingly demonstrated to follow this formation pathway. We obtained new interferometric observations of the directly imaged giant planet AF Lep b with the VLTI/GRAVITY instrument. We present three epochs of ∼50 μas relative astrometry and the K-band spectrum of the planet for the first time at a resolution of R = 500. Using only these measurements, spanning less than 2 months, and the Hipparcos-Gaia Catalogue of Accelerations, we are able to significantly constrain the planet’s orbit; this bodes well for interferometric observations of planets discovered by Gaia DR4. Including all available measurements of the planet, we infer an effectively circular orbit (e < 0.02, 0.07, and 0.13 at 1σ, 2σ, and 3σ, respectively) in spin–orbit alignment with the host and measure a dynamical mass of M p = 3.75M Jup ± 0.5M Jup. Models of the spectrum of the planet show that it is metal-rich ([M/H] = 0.75 ± 0.25), with a C/O abundance encompassing the solar value. This ensemble of results shows that the planet is consistent with core accretion formation.

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Implications of the discovery of AF Lep b

Cited by 3 publications

References 109 publications

Discovery of the Remarkably Red L/T Transition Object VHS J183135.58-551355.9

Discovery of the Remarkably Red L/T Transition Object VHS J183135.58-551355.9

Deep imaging of three accelerating stars using SHARK-NIR and LMIRCam at LBT

VLTI/GRAVITY Observations of AF Lep b: Preference for Circular Orbits, Cloudy Atmospheres, and a Moderately Enhanced Metallicity

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