HR 8799 e Archives - Astrobiology

Exoplanet 29 Cygni b, seen in this artist’s concept, is a gas giant weighing about 15 times the mass of Jupiter. It orbits a type A star (shown at upper right) slightly hotter and more massive than our Sun, at an average distance of 2.4 billion kilometres.-- Credit: NASA, ESA, CSA, J. Olmsted (STScI)

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Status Report, Stellar Cartography

Webb Redefines The Dividing Line Between Planets And Stars

by Keith CowingApril 14, 2026April 14, 2026

Planets, like those in our Solar System, form in a bottom-up process where small bits of rock and ice clump together and grow larger over time. But the heftier the […]

SED of 51 Eri b and best-fitting Exo-REM models. The top panel illustrates the transmission functions for each photometric filter. The middle panel shows the GPI (black circles, Macintosh et al. 2015; Rajan et al. 2017) and SPHERE (black squares, Samland et al. 2017; Brown-Sevilla et al. 2023) low-resolution spectra of the planet, as well as ground-based L’ and M band photometry (blue squares, Rajan et al. 2017), and the measurements from this work (gold hexagon, for our F410M detection, and gold downward facing triangles for our F335M, F430M, and F460M nondetections). Over plotted is the best-fitting Exo-REM model in magenta, and then 1, 2 σ envelopes showing the range of accepted models. The bottom panel illustrates the residuals to the best-fitting model; there are noticeable residuals in the J band GPI spectrum and the H band SPHERE spectrum that could be related to speckle noise or instrument throughput. The fit shows good agreement to the L’ band and F410M photometry, which constrain the CH4 and CO2 absorption slopes. The M band photometry from Rajan et al. (2017) lies slightly above the best-fitting model, but in general is consistent with strong CO absorption due to vertical mixing. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

JWST-TST High Contrast: Living on the Wedge, or, NIRCam Bar Coronagraphy Reveals CO2 in the HR 8799 and 51 Eri Exoplanets’ Atmospheres

by Keith CowingMarch 19, 2025March 19, 2025

High-contrast observations with JWST can reveal key composition and vertical mixing dependent absorption features in the spectra of directly imaged planets across the 3-5 μm wavelength range.

NASA’s James Webb Space Telescope has provided the clearest look in the infrared yet at the iconic multi-planet system HR 8799. The closest planet to the star, HR 8799 e, orbits 1.5 billion miles from its star, which in our solar system would be located between the orbit of Saturn and Neptune. The furthest, HR 8799 b, orbits around 6.3 billion miles from the star, more than twice Neptune’s orbital distance. Colors are applied to filters from Webb’s NIRCam (Near-Infrared Camera), revealing their intrinsic differences. A star symbol marks the location of the host star HR 8799, whose light has been blocked by the coronagraph. In this image, the color blue is assigned to 4.1 micron light, green to 4.3 micron light, and red to the 4.6 micron light. NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Press Release

Webb Telescope Images Young and Giant Exoplanets, Detects Carbon Dioxide

by Keith CowingMarch 17, 2025March 17, 2025

NASA’s James Webb Space Telescope has captured direct images of multiple gas giant planets within an iconic planetary system. HR 8799, a young system 130 light-years away, has long been […]

Directly-imaged exoplanets accrete on average ⪆50 M⊕ solids to enrich their atmospheres. Each violin shape shows the inferred accretion solid mass distribution (vertical axis) for a directly-imaged exoplanet. The median of the overall distribution is represented by the white point, and the 25% and 75% percentiles are represented by the thick line. An average value of 53.5 M⊕ is given as the horizontal dotted line. -- astro-ph.EP

Astrochemistry, Astrogeology, Brown Dwarfs, Exoplanets, -moons, -comets, Interstellar, Status Report

Early Accretion of Large Amounts of Solids for Directly-Imaged Exoplanets

by Keith CowingFebruary 10, 2025February 10, 2025

As the number of planetary mass objects (PMOs, ⪅13 MJupiter) at wider separation (⪆10 AU) grows, there is emerging evidence that they form differently from their higher-mass brown-dwarf (BD) counterparts.

Top: The full spectrum of VHS 1256 b using JWST’s NIRSpec IFU and MIRI MRS observation modes. Bandpasses are highlighted with different colors and error bar are displayed in grey. A single photometric point for MIRI MRS Channel 4A is shown because there is little to no signal in the MIRI MRS 4B, and 4C channels. Error bars are plotted in a light grey. Bottom: The wavelength overlap region between JWST’s NIRSpec IFU (black) and MIRI MRS (red) observation modes with errors plotted in light gray. The flux calibrated NIRSpec IFU spectra agree well with the MIRI MRS extracted spectra in the overlap region. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b

by Keith CowingJuly 23, 2024July 22, 2024

We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a <20 MJup widely separated (∼8 arcsec, a = 150 au), young, planetary-mass companion […]