TESS Dates an Ancient Collision With Our Galaxy

A single bright star in the constellation of v Indus, visible from the southern hemisphere, has revealed new insights on an ancient collision that our galaxy, the Milky Way, underwent with another smaller galaxy called Gaia-Enceladus early in its history.  (Image: via   Troy Oakes Photography  )
A single bright star in the constellation of v Indus, visible from the southern hemisphere, has revealed new insights on an ancient collision that our galaxy, the Milky Way, underwent with another smaller galaxy called Gaia-Enceladus early in its history. (Image: via Troy Oakes Photography )

An international team of scientists led by the University of Birmingham adopted the novel approach of applying the forensic characterization of a single ancient, bright star called ν Indi as a probe of the history of the Milky Way.  Stars carry “fossilized records” of their histories and hence the environments in which they formed. The team used data from satellites and ground-based telescopes to unlock this information from ν Indi. Their results are published in the journal Nature Astronomy.

The star was aged using its natural oscillations (asteroseismology), detected in data collected by NASA’s recently launched Transiting Exoplanet Survey Satellite (TESS). Launched in 2018, TESS is surveying stars across most of the sky to search for planets orbiting the stars and to study the stars themselves.

Artist concept of Transiting Exoplanet Survey Satellite. Image: NASA's Goddard Space Flight Center/Chris Meaney)

Artist concept of Transiting Exoplanet Survey Satellite. (Image: NASA’s Goddard Space Flight Center/Chris Meaney)

When combined with data from the European Space Agency’s (ESA) Gaia Mission, the detective story revealed that this ancient star was born early in the life of the Milky Way, but the Gaia-Enceladus collision altered its motion through our Galaxy. Bill Chaplin, Professor of Astrophysics at the University of Birmingham and lead author of the study, said:

Co-author Dr. Ted Mackereth, also from Birmingham, said:

Bill Chaplin added:

The research clearly shows the strong potential of the TESS program to draw together rich new insights about the stars that are our closest neighbors in the Milky Way. The research was funded by the Science and Technology Facilities Council and the European Research Council through the Asterochronometry Project.

Provided by: University of Birmingham [Note: Materials may be edited for content and length.]

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