Utilizing NASA’s James Webb Area Telescope (JWST), astronomers have noticed a close-by brown dwarf often called HD 19467 B. Outcomes of the observational marketing campaign, revealed January 26 on the arXiv pre-print server, yield vital insights into the properties of this substellar object.
Brown dwarfs are intermediate objects between planets and stars. Astronomers usually agree that they’re substellar objects occupying the mass vary between 13 and 80 Jupiter lots. One subclass of brown dwarfs (with efficient temperatures between 500 and 1,500 Okay) is called T dwarfs, and represents the good and least luminous substellar objects to date detected.
Research of T dwarfs may assist astronomers higher perceive objects close to the disputed planet/star boundary, for example, big exoplanets. Nonetheless, though many brown dwarf have been detected to this point, T dwarfs are usually not so widespread, as solely about 400 such objects have been recognized.
At a distance of some 100 light years from the Earth, HD 19467 B is a late T dwarf with a floor temperature of about 1,000 Okay. It orbits HD 19467—a sun-like star of spectral sort G3V, estimated to be between 5.4 and 12 billion years previous. The star’s efficient temperature was measured to be roughly 5,750 Okay.
A staff of astronomers led by Alexandra Z. Greenbaum of the California Institute of Know-how (Caltech) used JWST to carry out medium/slim band imaging and photometry of HD 19467 and its companion, hoping to unveil basic parameters of the brown dwarf. The examine was complemented by knowledge from NASA’s Transiting Exoplanet Survey Satellite tv for pc (TESS).
“We noticed HD 19467 B with JWST’s NIRCam in six filters spanning 2.5–4.6 µm with the Lengthy Wavelength Bar coronagraph…. JWST observations of the G3V star HD 19467 with its T5+ brown dwarf companion, HD 19467 B, symbolize one of many earliest workout routines of the NIRCam Coronagraphic LW Bar, offering a chance for an early scientific end result and an indication of the capabilities of the instrument,” the researchers wrote within the paper.
The observations allowed the staff to constrain the properties of HD 19467, notably its age. The outcomes recommend that the host star is roughly 9.4 billion years previous. The star’s radius was measured to be about 1.2 solar radii, whereas its mass was estimated to be some 0.96 solar masses.
Based on the examine, the dynamical mass of the brown dwarf was calculated to be at a degree of 81 Jupiter lots and its model-derived mass was estimated to be 62 Jupiter lots. The researchers famous that the radius of HD 19467 B is at a degree of 0.62 Jupiter radii and that its floor temperature is roughly 10,800 Okay.
Greenbaum’s staff plans additional JWST observations of HD 19467 B, later this 12 months, with the primary intention of characterizing the environment of this brown dwarf.
Extra data:
Alexandra Z. Greenbaum et al, First Observations of the Brown Dwarf HD 19467 B with JWST, arXiv (2023). DOI: 10.48550/arxiv.2301.11455
Journal data:
arXiv
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JWST observations shed extra mild on the properties of a close-by brown dwarf (2023, February 7)
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