Astronomers have discovered three young stars in the Milky Way’s nuclear star cluster. The stars are estimated to be between 100 million and 1 billion years old, which is relatively young compared to the Sun’s age of 4.6 billion years. The discovery shows that there is active star formation in the Milky Way, which was previously thought to be ancient
The nuclear star cluster is one of the oldest parts of the Milky Way. The researchers studied the stars’ infrared light spectra to calculate the iron content
The oldest of these stars is 1.5 billion years old while the youngest is only 100 million years old, according to a paper published in the Astrophysical Journal Letters.
According to a study, three stars in the Milky Way are estimated to be between 100 million and 1 billion years old. This is relatively young compared to the Sun, which is 4.6 billion years old.
Most stars are between 1 billion and 10 billion years old. Some stars may be close to 13.8 billion years old, which is the estimated age of the universe. The lifetime of a star depends on its mass. Lighter stars have a longer lifetime.
The most common technique used to determine the age of stars is called isochrone fitting. This technique compares the observed colors and brightnesses of stars.
The Milky Way galaxy contains between 100 and 400 billion stars. It also has at least that many planets. The Milky Way is about 100,000 light-years across.
The Milky Way produces about seven stars each year. It has converted about 90% of its gas content into stars.
The Milky Way has about 20 billion sunlike stars. However, for every star that can be seen, there are more than 20 million that cannot be seen. Most of the stars are too faint, too far away, or blocked by cosmic dust.
The Milky Way is producing about four solar masses of gas into stars each year.
The Milky Way is a barred spiral galaxy. Barred spiral galaxies are a subtype of spiral galaxies, which are disk-shaped galaxies with spiral arms. Barred spiral galaxies have a central bar-shaped structure. The Milky Way and Andromeda galaxies are both barred spirals
Yes, isochrone fitting is the most common technique used to determine the age of stars. It compares the observed colors and brightnesses of stars with the expected ones from theoretical predictions
Isochrone fitting is also a standard approach to determine the age of globular clusters. It can be solved with a least-square method, where the data to be fitted are the points on the color-magnitude diagram and the fitting curve is the isochrone.
Isochrone fitting also estimates the age, radius, mass, and evolutionary phase of a star defined by its effective temperature and luminosity
Some isochrone fitting methods for globular clusters include:
- NGC 288, NGC 362, and NGC 6218 (M12): Uses photometric bands from ultraviolet to mid-infrared from the HST, Gaia, unWISE, Pan-STARRS, and other sources
- NGC 6205 (M13): Uses 34 photometric bands from ultraviolet to mid-infrared from the HST, Gaia DR2, SDSS, unWISE, Pan-STARRS DR1, and other sources
- NGC 1261 and NGC 1851: Uses the PAdova and TRieste Stellar Evolution Code (PARSEC)
Other methods include:
- Using the Dartmouth Stellar Evolution Program
- Using the MESA Isochrones and Stellar Tracks
- Using a Bag of Stellar Tracks and Isochrones
The traditional method for isochrone fitting is to:
- Determine reddening by adjusting a Zero Age Main Sequence (ZAMS) to the cluster’s observed color-color diagram
- Keep the reddening value fixed
- Adjust the distance and age using the observed CMD and tabulated isochrones
Isochrone fitting can also use several isochrones that are the same in all respects but one. The isochrones are then overlaid onto the HR diagram of the cluster to see which one matches the best. (Full article source google)
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