Discovering new worlds with quantitative spectroscopy

Astronomers from the Leibniz Institute for Astrophysics Potsdam (AIP) and the Vatican Observatory (VO) teamed as much as spectroscopically survey greater than 1,000 shiny stars that doubtlessly host exoplanets.

The staff presents exact values of 54 spectroscopic parameters per star within the first of a collection of papers within the journal Astronomy & Astrophysics and launched all its knowledge to the scientific neighborhood. This unprecedented giant variety of parameters might be important to deciphering the stellar mild and discovering connections between the celebrities’ properties and their probably nonetheless unknown planets.

Stars inform tales about themselves, and generally about their undiscovered planets. Their language is mild; it reveals many bodily properties of a star, together with its temperature, stress, movement, and chemical composition. Researchers analyze the sunshine with a way referred to as quantitative absorption spectroscopy.

Telescopes seize starlight and spectrographs break it up by wavelength right into a rainbow-like spectrum which is the star’s mild fingerprint. When astronomers know these parameters exactly, they’ll use them to check their theoretical fashions of stars. This typically reveals that the fashions have some shortcomings, or that observations of stellar spectra are nonetheless too imprecise.

However generally, it reveals {that a} star has a stunning story for astronomers. That’s what motivated this staff to make an ultra-precise survey of doable planet-hosting stars.

“As a result of stars and their planets type collectively, the query arose whether or not the existence of sure chemical components in a stellar ambiance, or their isotopic or abundance ratios, is indicative of a planetary system,” explains Prof. Klaus G. Strassmeier, lead writer, director at AIP and principal investigator of the survey.

Astronomers have hypothesized that the quantities of various chemical components inside a star might trace that the star has terrestrial planets (rocky worlds like Earth or Mars), might counsel ages for these planets, and will even present clues that the star has “eaten” a few of its planets. It will want additional investigation, and the now launched knowledge lay the foundations for such research.

Of the over 5,000 confirmed exoplanets (planets orbiting different stars than the Solar), 75% had been found from space by observing a star’s mild being lowered due to a planet transiting in entrance of it. NASA’s Transiting Exoplanet Survey Satellite tv for pc (TESS) mission found exoplanets simply this manner.

It yielded extra exoplanets when observing these components of the sky furthest from the ecliptic (the airplane by which the Earth orbits the Solar), referred to as the ecliptic poles. Observatories within the northern hemisphere can observe the Northern Ecliptic Pole, and this survey of potential planet-hosting stars inside this area is known as the Vatican-Potsdam Northern Ecliptic Pole (VPNEP) survey.

The survey targeting the richest observing area of TESS, an space of the sky roughly 4,000 instances the dimensions of the full moon. All roughly 1,100 doubtlessly planet-hosting stars on this area had been investigated. As much as 1.5 hours of telescope time was required to collect sufficient of a star’s mild to make a single high-quality spectrum. With a number of visits per star, it took 5 years to acquire the survey knowledge.

The survey made use of telescopes at two websites: In Arizona, the VO’s Alice P. Lennon Telescope and Thomas. J. Bannan Astrophysics Facility (Vatican Superior Expertise Telescope or VATT) fed mild to the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) and took spectra of dwarf stars with unprecedented precision. On Tenerife, the AIP’s STELLA (STELLar Exercise) Observatory used the STELLA Echelle Spectrograph to seize mild of big stars with decrease, however nonetheless excessive, precision.

Dr. Martina Baratella, one in all AIP’s postdoctoral researchers concerned within the survey, feedback, “The spectra revealed components which can be among the many most tough to look at.” Abundance ratios like carbon to iron or magnesium to oxygen trace in direction of the existence and age of in any other case unseen rocky planets. Prof. Strassmeier provides, “Whereas it should take time to completely analyze the information from the survey, we anticipate quickly to announce subsequent discoveries.”