How many stars in our galaxy
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Number of Stars in the Milky Way Galaxy
Estimations of Star Count in the Milky Way
The Milky Way galaxy, our cosmic home, is a vast and complex structure containing an immense number of stars. Estimating the exact number of stars in the Milky Way is a challenging task due to the galaxy's size and the limitations of our observational technologies. However, various studies and surveys provide valuable insights into the star count.
Surveys and Catalogs
Optical Gravitational Lensing Experiment (OGLE)
The OGLE project has identified nearly 66,000 Mira-type variable stars in the Milky Way, with a significant portion located in the Galactic bulge and disk1. This extensive catalog helps in understanding the distribution and characteristics of variable stars, contributing to the broader estimation of the total star count.
Gaia Data Release 2 (DR2)
The Gaia mission's second data release includes detailed measurements of over 7 million stars, providing crucial data on their positions, parallaxes, proper motions, and radial velocities2. This comprehensive dataset allows astronomers to map the Milky Way's structure and estimate the number of stars more accurately.
Catalogue of Mean UBV Data on Stars
A reference work containing data on the magnitudes of more than 100,000 stars in the galaxy has been compiled, offering a significant resource for understanding the distribution and properties of stars4. This catalog is essential for various astronomical studies and helps refine the estimates of the total star count.
Estimations from Star Counts and Models
Galactic Structure Studies
Star counts carried out with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope have provided insights into the vertical distribution of stars in the Milky Way. The study suggests that the galaxy's structure includes a thin disk, a thick disk, and a halo, each contributing to the overall star count7. These structural components are crucial for accurate star count estimations.
Low-Mass Stars in the Spheroid
Research indicates that the number of stars in the spheroid of our galaxy increases steeply for smaller masses, with no evidence of a turnover in a simple power-law distribution down to the limit of detectability9. This finding implies a significant population of low-mass stars, which must be considered in total star count estimations.
Conclusion
Combining data from various surveys and studies, astronomers estimate that the Milky Way contains between 100 billion to 400 billion stars. This range accounts for the different types of stars, including variable stars, low-mass stars, and those in various galactic components such as the bulge, disk, and halo. While precise numbers are challenging to determine, ongoing advancements in observational technologies and data analysis continue to refine our understanding of the Milky Way's stellar population.
Sources and full results
Most relevant research papers on this topic
The OGLE Collection of Variable Stars: Nearly 66,000 Mira Stars in the Milky Way
The OGLE database contains 65,981 Mira-type variable stars, with most new discoveries, and can be used as a training set for machine-learning classification algorithms.
Gaia DR2 in 6D: searching for the fastest stars in the Galaxy
Gaia DR2 data reveals that 13 unbound stars, including two of the fastest stars (around 700 km s1), may be the tip of the iceberg of a large extragalactic population or the extreme velocity tail of stellar streams.
Highly CitedVariable Stars in Local Group Galaxies. VI. The Isolated Dwarfs VV 124 and KKr 25
Variable stars have been discovered in isolated dwarf galaxies VV 124 and KKr 25, suggesting both galaxies are fairly metal-poor and may contain an intrinsic spread in metallicity.
Photometry-based estimation of the total number of stars in the Universe.
The total number of stars in the Universe is about 61022, based on energy conservation law and extragalactic background light levels.
Galactic structure studies with BATC star counts
The Milky Way's star distribution is shaped by two exponential disks and a de Vaucouleurs halo, with a flattened inner halo and a spherical outer halo.
Discovery of a nearby isolated neutron star
A bright soft-X-ray source at a distance of 100 parsecs confirms our understanding of how isolated neutron stars should appear, but highlights the need to account for the absence of others that should be visible.
Highly CitedA systematic survey for infrared star clusters with |b| < 20° using 2MASS
Star clusters tend to cluster on spatial scales of 12-25pc, indicating a molecular cloud-like distribution in the Galaxy.
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