Astronomers with the help of the Hubble Space Telescope have found a new record-breaking star – light from WHL0137-LS or “Earendil” went to Earth 12.9 billion years ago. It is assumed that this is a single and very hot light, the mass of which is more than 40 times the mass of the Sun. The article was published in a journal Nature.
The effect of gravitational lensing occurs due to the fact that the astronomical object with its gravitational field distorts and amplifies the light of the background object as it passes between it and the observer. The more massive the object-lens, the stronger it can affect the direction of propagation of electromagnetic radiation. In the case of galaxies or clusters of galaxies that act as a lens, it is possible to see objects behind them, such as galaxies, supernovae or stars. The magnification of such lenses can reach tens or hundreds of times for galaxies whose images are drawn in arcs, or thousands of times for individual stars.
A team of astronomers led by Brian Welch of Johns Hopkins University in Baltimore has announced the discovery of the longest star to date, found during an analysis of the RELICS (Reionization Lensing Cluster Survey) survey conducted by the Space Television Observatory. .
One of the purposes of observations was the arc of the lens galaxy WHL0137-zD1, which was designated “Sunrise Arc” (Sunrise Arc) and is characterized by a value of redshift z = 6.2. The arc is visible due to the gravitational lens, which acts as a cluster of galaxies WHL0137-08, characterized by a redshift value of z = 0.566. In the arc, scientists have found a greatly magnified star at the top of the critical lensing curve – it was designated WHL0137-LS or “Earendel” (Earendel, “morning star”).
The absolute stellar magnitude of the star, determined in the ultraviolet range, is estimated at −10, which corresponds to a single and very massive star. It can be either a massive O-type star on the main sequence, with an effective temperature of about 60,000 kelvins and a mass of more than one hundred solar masses, or a pro-evolving, O-, B- or A-type star with a mass of more than 40 masses. Sun and temperatures from 8 to 60 thousand kelvins. The star existed at a time when the age of the universe was 900 million years. Confirmation of the discovery and spectral classification of the star will be obtained during future planned observations using the James Webb Space Telescope.
The previous record-breaking star was LS1 or Icarus, which existed at a time when the universe was about 4.4 billion years old.