Unusual polarimetric properties for interstellar comet 2I/Borisov

So far, only two interstellar objects have been observed within our Solar System. While the first one, 1I/‘Oumuamua, had asteroidal characteristics, the second one, 2I/Borisov, showed clear evidence of cometary activity. We performed polarimetric observations of comet 2I/Borisov using the European Southern Observatory Very Large Telescope to derive the physical characteristics of its coma dust particles. Here we show that the polarization of 2I/Borisov is higher than what is typically measured for Solar System comets. This feature distinguishes 2I/Borisov from dynamically evolved objects such as Jupiter-family and all short- and long-period comets in our Solar System. The only object with similar polarimetric properties as 2I/Borisov is comet C/1995 O1 (Hale-Bopp), an object that is believed to have approached the Sun only once before its apparition in 1997. Unlike Hale-Bopp and many other comets, though, comet 2I/Borisov shows a polarimetrically homogeneous coma, suggesting that it is an even more pristine object.

From the Leviathan to the Behemoth

The world’s biggest telescopes are reflectors and every increase in size has given us a new perspective on the universe. The Rosse telescope, built in the middle of the nineteenth century by Lord Rosse in County Offaly, Ireland, was nicknamed the Leviathan of Parsonstown. It was the world’s biggest telescope for over half a century. Rosse’s drawings of the celestial objects that he viewed through the telescope were widely circulated. His drawing of the Whirlpool Galaxy is thought to have inspired Van Gogh’s painting Starry Night. The European Southern Observatory (ESO) is now constructing the Extremely Large Telescope (ELT) in Chile. It will be the largest telescope in the world when completed.

Space videos on YouTube - what makes the audience tick

Nowadays it is easier than ever before to produce films and videos and make them available to a worldwide audience via platforms such as YouTube, Twitter and Facebook, among others. The European Space Agency (ESA), the European Southern Observatory (ESO), the National Aeronautics and Space Administration (NASA), and other similar organisations constantly produce videos aimed at the general interested audience, and distribute them on through their social media channels. Different formats are offered such as educational, informative, news style, science stories, scientist profiles, behind-the-scenes, animations and data based animations. But which of these formats do really stick and why? A simple statistical analysis of 106 videos found on the ESA, ESO and NASA YouTube channels shows that videos based on animations and the representation of data, with little to no explanation and accompanied by music are the more popular in terms of views per month by about a factor of two compared to other types of videos. This can likely be explained by the higher entertainment value of such videos.

Astronomia chilena: efeito da concentração da produção científica sobre os indicadores de um país

Neste trabalho analisamos os indicadores de produção científica, número de artigos e citações, para diferentes áreas do conhecimento, em particular Astronomia e Astrofísica de autores lotados em instituições chilenas. A motivação para a análise foi a disseminação de um ranking baseado em informações incompletas, mas que repercutiu em comunidades interessadas em indicadores bibliométricos. A análise no nível de subáreas do conhecimento mostra como a concentração de produção e citações em apenas uma área pode influenciar médias gerais e eventuais posições em rankings. Verifica-se também o peso que uma única instituição, o European Southern Observatory (ESO), pode apresentar nos indicadores gerais de um país. Uma rede de coautoria envolvendo pesquisadores do ESO é construída e analisada, revelando algumas características das colaborações em grandes ambientes de pesquisa voltadas à Astronomia.

Bibliography of the works by Piotr Flin (1945–2018), an astronomer and exact sciences historian

The bibliography presents the list of publications by Piotr Flin (1945–2018), an astronomer and exact sciences historian. This study presents a list of two hundred and fifty (including two hundred and forty-three separate) publications of the late Piotr Flin and a list of three doctoral theses he supervised. It is likely that the list of publications presented is not a complete bibliography of the author’s works. Due to the specificity of the study, the co-authored publications are listed in a chronological order, not an alphabetical order of co-authors. In addition, compared to the standard bibliographical style adopted in the journal, the date of publication appears at the end of each bibliographic record in square brackets. Providing the date in this format follows the convention adopted on the SAO / NASA portal Astrophysics Data System and its enriched copy: “The Science Archive Facility” at the European Southern Observatory. In accordance with the conventions adopted in the aforementioned portals, the list of publications also includes two reviews of a co-authored monograph by P. Flin.

Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS

Aims. Carbon-enhanced metal-poor (CEMP) stars represent a sizeable fraction of all known metal-poor stars in the Galaxy. Their formation and composition remains a significant topic of investigation within the stellar astrophysics community. Methods. We analysed a sample of low-resolution spectra of 30 dwarf stars, obtained using the visual and near UV FOcal Reducer and low dispersion Spectrograph for the Very Large Telescope (FORS/VLT) of the European Southern Observatory (ESO) and the Gemini Multi-Object Spectrographs (GMOS) at the GEMINI telescope, to derive their metallicity and carbon abundance. Results. We derived C and Ca from all spectra, and Fe and Ba from the majority of the stars. Conclusions. We have extended the population statistics of CEMP stars and have confirmed that in general, stars with a high C abundance belonging to the high C band show a high Ba-content (CEMP-s or -r/s), while stars with a normal C abundance or that are C-rich, but belong to the low C band, are normal in Ba (CEMP-no).

Calibration of EFOSC2 Broadband Linear Imaging Polarimetry

The European Southern Observatory Faint Object Spectrograph and Camera v2 is one of the workhorse instruments on ESO’s New Technology Telescope, and is one of the most popular instruments at La Silla observatory. It is mounted at a Nasmyth focus, and therefore exhibits strong, wavelength and pointing-direction-dependent instrumental polarisation. In this document, we describe our efforts to calibrate the broadband imaging polarimetry mode, and provide a calibration for broadband B, V, and R filters to a level that satisfies most use cases (i.e. polarimetric calibration uncertainty ~0.1%). We make our calibration codes public. This calibration effort can be used to enhance the yield of future polarimetric programmes with the European Southern Observatory Faint Object Spectrograph and Camera v2, by allowing good calibration with a greatly reduced number of standard star observations. Similarly, our calibration model can be combined with archival calibration observations to post-process data taken in past years, to form the European Southern Observatory Faint Object Spectrograph and Camera v2 legacy archive with substantial scientific potential.