We investigate the properties of AGB and post-AGB (PAGB) stars, planetary nebulae, and young stellar objects (YSOs) in our Galaxy through an analysis of observational data covering visual and infrared (IR) wavelengths. Utilizing datasets from IRAS, 2MASS, AllWISE, Gaia DR3, and the SIMBAD object database, we perform an in-depth comparison between observational data and theoretical models. For this comparison, we present various color-magnitude diagrams (CMDs) in visual and IR bands, as well as IR two-color diagrams (2CDs). Our results demonstrate that the CMDs, incorporating the latest distance and extinction data from Gaia DR3 for a majority of sample stars, are effective in distinguishing different classes of stars. To improve the precision of our analysis, we apply theoretical radiative transfer models for dust shells around AGB and PAGB stars. A thorough comparison of the theoretical models with observations across various IR 2CDs and CMDs shows a significant agreement. We find that AGB and PAGB stars are among the brightest classes in visual and IR bands. Furthermore, most YSOs are clearly distinguishable from AGB stars on various IR CMDs, exhibiting fainter absolute magnitudes in IR bands.

Introduction
Sample Stars in our Galaxy 
    AGB and Post-AGB Stars
    Planetary Nebulae 
    Young Stellar Objects 
    Photometric Data 
    Cross-Identification
    Distances and Galactic Extinction 
Properties in Visual Bands
Theoretical Dust Shell Models
    Models for AGB Stars
    Models for Post-AGB Stars
    Limitations of the Theoretical Models
Properties in IR Bands
    IR 2CDs
    IR CMDs
    Overall IR Properties
    YSOs and AGB Stars
Summary
Acknowledgments
References

• Kyung-Won Suh(Department of Astronomy and Space Science, Chungbuk National University, Chungcheongbuk-do 28644, Republic of Korea) Corresponding author