Search Publications
Direct imaging and astrometric detection of a gas giant planet orbiting an accelerating star
Burrows, Adam; Currie, Thayne; Kwon, Jungmi +31 more
Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures of planetary systems. However, few planets have been detected in blind surveys with direct imaging. Using astrometry from the Gaia and Hipparcos spacecraft, we identified dynamical evidence for a gas giant planet around the nearby star HIP 99770.…
An observed population of intermediate-mass helium stars that have been stripped in binaries
Smith, N.; de Mink, S. E.; Drout, M. R. +4 more
The hydrogen-rich outer layers of massive stars can be removed by interactions with a binary companion. Theoretical models predict that this stripping produces a population of hot helium stars of ~2 to 8 solar masses (M☉), however, only one such system has been identified thus far. We used ultraviolet photometry to identify potential st…
The distribution of CO2 on Europa indicates an internal source of carbon
Brown, Michael E.; Trumbo, Samantha K.
Jupiter’s moon Europa has a subsurface ocean, the chemistry of which is largely unknown. Carbon dioxide (CO2) has previously been detected on the surface of Europa, but it was not possible to determine whether it originated from subsurface ocean chemistry, was delivered by impacts, or was produced on the surface by radiation processing …
A massive helium star with a sufficiently strong magnetic field to form a magnetar
Wade, Gregg A.; Toonen, Silvia; Sana, Hugues +13 more
Magnetars are highly magnetized neutron stars, the formation mechanism of which is unknown. Hot helium-rich stars with spectra dominated by emission lines are known as Wolf-Rayet stars. We observed the binary system HD 45166 using spectropolarimetry and reanalyzed its orbit using archival data. We found that the system contains a Wolf-Rayet star w…
Picoflare jets power the solar wind emerging from a coronal hole on the Sun
Barczynski, K.; Peter, H.; Chitta, L. P. +17 more
Coronal holes are areas on the Sun with open magnetic field lines. They are a source region of the solar wind, but how the wind emerges from coronal holes is not known. We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft. We identified jets on scales of a few hundred kilometers, which last 20 to 100 seco…
Inspiraling streams of enriched gas observed around a massive galaxy 11 billion years ago
Fan, Xiaohui; Cai, Zheng; Li, Qiong +19 more
Stars form in galaxies, from gas that has been accreted from the intergalactic medium. Simulations have shown that recycling of gas—the reaccretion of gas that was previously ejected from a galaxy—could sustain star formation in the early Universe. We observe the gas surrounding a massive galaxy at redshift 2.3 and detect emission lines from neutr…
A cosmic stream of atomic carbon gas connected to a massive radio galaxy at redshift 3.8
Lehnert, Matthew D.; De Breuck, Carlos; Mandelker, Nir +7 more
The growth of galaxies in the early Universe is driven by accretion of circum- and intergalactic gas. Simulations have predicted that steady streams of cold gas penetrate the dark matter halos of galaxies and provide the raw material necessary to sustain star formation. We report a filamentary stream of gas that extends for 100 kiloparsecs and con…
Element abundance patterns in stars indicate fission of nuclei heavier than uranium
Beers, Timothy C.; Placco, Vinicius M.; Holmbeck, Erika M. +9 more
The heaviest chemical elements are naturally produced by the rapid neutron-capture process (r-process) during neutron star mergers or supernovae. The r-process production of elements heavier than uranium (transuranic nuclei) is poorly understood and inaccessible to experiments so must be extrapolated by using nucleosynthesis models. We examined el…
Evidence for a radiation belt around a brown dwarf
Pérez-Torres, M.; Guirado, J. C.; Marcaide, J. M. +2 more
Ultracool dwarfs (UCDs) are a category of astronomical objects that includes brown dwarfs and very-low-mass stars. Radio observations of UCDs have measured their brightness as a function of time (light curves) and spectral energy distributions, providing insight into their magnetic fields. We present spatially resolved radio observations of the br…
Optical polarization from colliding stellar stream shocks in a tidal disruption event
Blinov, D.; Liodakis, I.; Berton, M. +9 more
A tidal disruption event (TDE) occurs when a supermassive black hole rips apart a passing star. Part of the stellar material falls toward the black hole, forming an accretion disk that in some cases launches a relativistic jet. We performed optical polarimetry observations of a TDE, AT 2020mot. We find a peak linear polarization degree of 25 ± 4%,…