Search Publications
A plague of magnetic spots among the hot stars of globular clusters
Gullieuszik, M.; Milone, A. P.; Stetson, P. B. +15 more
For more than six decades, the quest to understand the formation of hot (about 20,000-30,000 K) extreme horizontal branch (EHB) stars in Galactic globular clusters has remained one of the most elusive in stellar evolutionary theory. Here we report on two discoveries that challenge the idea of the stable luminosity of EHB stars. The first mode of E…
Diffuse X-ray emission around an ultraluminous X-ray pulsar
Wolter, Anna; Pintore, Fabio; Mereghetti, Sandro +17 more
Ultraluminous X-ray sources (ULXs) are extragalactic X-ray emitters located off-centre of their host galaxy and with a luminosity in excess of a few 1039 erg s-1, if emitted isotropically1,2. The discovery of periodic modulation revealed that in some ULXs the accreting compact object is a neutron star3-7…
A year-long plateau in the late-time near-infrared light curves of type Ia supernovae
Ryan, R.; Maguire, K.; Graur, O. +6 more
The light curves of type Ia supernovae are routinely used to constrain cosmology models. Driven by radioactive decay of 56Ni, the light curves steadily decline over time, but after 150 d post-explosion the near-infrared portion is poorly characterized. We report a year-long plateau in the near-infrared light curve at 150-500 d, followed…
An ablating 2.6 M⊕ planet in an eccentric binary from the Dispersed Matter Planet Project
Jenkins, James S.; Anglada-Escudé, Guillem; Díaz, Matías R. +8 more
Earth-mass exoplanets are difficult to detect. The Dispersed Matter Planet Project (DMPP) identifies stars that are likely to host the most detectable low-mass exoplanets. The star DMPP-3 (HD 42936) shows signs of circumstellar absorption, indicative of mass loss from ablating planets. Here, we report the radial velocity discovery of a highly ecce…
Far-ultraviolet aurora identified at comet 67P/Churyumov-Gerasimenko
Altwegg, K.; Feldman, P. D.; Carr, C. +14 more
Having a nucleus darker than charcoal, comets are usually detected from Earth through the emissions from their coma. The coma is an envelope of gas that forms through the sublimation of ices from the nucleus as the comet gets closer to the Sun. In the far-ultraviolet portion of the spectrum, observations of comae have revealed the presence of atom…
A giant galaxy in the young Universe with a massive ring
Kacprzak, Glenn G.; Glazebrook, Karl; Labbé, Ivo +12 more
In the local (redshift z ≈ 0) Universe, collisional ring galaxies make up only ~0.01% of galaxies1 and are formed by head-on galactic collisions that trigger radially propagating density waves2-4. These striking systems provide key snapshots for dissecting galactic disks and are studied extensively in the local Universe5…
Detection of green line emission in the dayside atmosphere of Mars from NOMAD-TGO observations
Aoki, S.; Vandaele, A. C.; Daerden, F. +13 more
The oxygen emission at 557.7 nm is a ubiquitous component of the spectrum of the terrestrial polar aurora and the reason for its usual green colour1. It is also observed as a thin layer of glow surrounding the Earth near 90 km altitude in the dayside atmosphere2,3 but it has so far eluded detection in other planets. Here we r…
Sustained formation of progenitor globular clusters in a giant elliptical galaxy
Broadhurst, Tom; Ohyama, Youichi; Medezinski, Elinor +2 more
Globular clusters (GCs) are thought to be ancient relics from the early formative phase of galaxies, although their physical origin remains uncertain1,2. GCs are most numerous around massive elliptical galaxies, where they can exhibit a broad colour dispersion, suggesting a wide metallicity spread3. Here, we show that many th…
The population of rotational fission clusters inside asteroid collisional families
Spoto, F.; Carruba, V.; Aljbaae, S. +3 more
Asteroid families are groups of objects sharing similar orbits. They are mostly the results of past collisions between two asteroids. Recent studies have shown that some asteroid families can also be the outcome of the spin-up-induced fission of a critically rotating parent body (fission clusters). In at least four young fission clusters, more tha…
A complex storm system in Saturn's north polar atmosphere in 2018
Hueso, R.; Sánchez-Lavega, A.; Simon, A. A. +15 more
Saturn's convective storms usually fall in two categories. One consists of mid-sized storms ∼2,000 km wide, appearing as irregular bright cloud systems that evolve rapidly, on scales of a few days. The other includes the Great White Spots, planetary-scale giant storms ten times larger than the mid-sized ones, which disturb a full latitude band, en…