From Henrietta to the center of the galaxy
From Henrietta to the center of the galaxy
It is known that astronomer Henrietta Swan Leavitt discovered that the period of Cepheid stars is intimately related to brightness, this property being used to calculate distances with extreme precision.
What was not so well known is that at the core of our galaxy there were extremely young Cepheids. "It is believed that the central bulb of the Milky Way is made up of a large number of old stars, but the VISTA data has revealed something new and very young by astronomical standards," says Istvan Dékány, lead author of the study carried out with data from the survey VVV (VISTA Variables in the Via Lactea).
Image 1: Diagram showing the location of the newly discovered Cepheids in an illustration of the Milky Way. Credits: ESO / Microsoft Worldwide Telescope.
And it is that a total of 655 Cepheid candidates have been found in the bulb of our Milky Way, where 35 of them have been classified as classic Cepheids and after analyzing them, scientists have been surprised by their extraordinary youth. "The 35 classical Cepheids discovered are less than 100 million years old, the youngest Cepheid may even be only 25 million years old, although we can not exclude the possible presence of even younger and brighter Cepheids," explains Dante Minniti. of the Andres Bello University (Chile), co-author of the study.
This finding provides solid evidence that new stars have been being born in the Milky Way bulb at least for the last 100 million years.
There is something more
After analyzing the nine Cepheids, the scientists observed a thin disk of young stars in the galactic bulb, invisible to previous soundings since it was buried behind dense clouds of dust but with VISTA it has been possible to observe.
"This part of the galaxy was totally unknown until our VVV survey discovered it," says Minniti. "It is a demonstration of the unique ability of the VISTA telescope to probe extremely obscured galactic regions that can not be studied in any other current or planned survey. the future ", adds Dékány.
VISTA is proving a very productive survey, because prior to this discovery it already had the discovery of other variable stars, new star clusters and star explosions.
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VVV is a public ESO survey conducted with the VISTA telescope that has the objective of obtaining images at different times from the central parts of the galaxy in five bands of the near infrared.
This research has been presented in the journal Astrophysical Journal Letters in an article entitled "The VVV Survey reveals classical Cepheids tracing a young and thin stellar disk across the Galaxy's bulge", by I. Dekany et al.
The team that has carried out the research consists of I. Dékány (Millennium Institute of Astrophysics, Chile, Pontificia Universidad Católica de Chile, Chile), D. Minniti (Andres Bello University, Chile, Instituto Milenio de Astrofísica MAS and Basal CATA , Chile, Vatican Observatory, Vatican City State), D. Majaess (Saint Mary's University, Canada, Mount Saint Vincent University, Canada), M. Zoccali (Pontificia Universidad Católica de Chile, Chile, Instituto Milenio de Astrofísica, Chile), G Hajdu (Pontifical Catholic University of Chile, Chile, Millennium Institute of Astrophysics, Chile), J. Alonso-Garcia (University of Antofagasta, Chile, Millennium Institute of Astrophysics, Chile), M. Catelan (Pontificia Universidad Católica de Chile, Chile Millennium Institute of Astrophysics, Chile), W. Gieren (University of Concepción, Chile, Millennium Institute of Astrophysics, Chile) and J. Borissova (University of Valparaíso, Chile, Millennium Institute of Astrophysics, Chi you).
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