Data source: ESA Gaia DR3
Teff at 37,563 K: A Distant Blue-White Giant
In the Gaia DR3 catalog, a luminous blue-white star shines with a surface that sparkles at a scorching temperature. Gaia DR3 4687491332258331776, a star cataloged by the European Space Agency’s Gaia mission, reports a Teff_gspphot of approximately 37,563 Kelvin. This is the kind of temperature that lights the sky with a distinctly blue-tinged glow and places the object among the hottest stars known in our galaxy. The same data package also reveals a moderately large radius—about 6 times the Sun’s size—hinting at a star that could be a hot main-sequence object or a blue giant, rather than a small, cool dwarf.
The combination of high temperature and a radius near six solar units is a powerful clue. It suggests a star whose energy output dwarfs the Sun and whose light shifts toward the blue end of the spectrum. In practical terms, a surface this hot makes the star appear blue-white to the eye if viewed up close. When we translate that temperature into color, the star would glow with a characteristic shade often associated with early-type O or B stars—a category of hot, luminous stars that blaze in ultraviolet and blue light.
Distance, Brightness, and What We See from Earth
The Gaia DR3 data place this star at a distance of about 28,159 parsecs from us, or roughly 28.16 kiloparsecs. Converted to light-years, that is on the order of 92,000 light-years away. To put that in perspective: light from this star has traveled for nearly 92 millennia before reaching our planet. At such a vast distance, the star is far beyond the reach of naked-eye visibility. Its photometric mean G-band magnitude, phot_g_mean_mag, is about 14.51. In practical terms, that means you would need a telescope to detect it; it would never appear to the unaided eye, even under exceptionally dark skies.
Yet distance does not erase color. The Gaia measurements also provide blue-white color indices through the Gaia BP and RP bands. With phot_bp_mean_mag ≈ 14.49 and phot_rp_mean_mag ≈ 14.41, the BP−RP color is around +0.09 magnitudes. This small, positive value is consistent with a star that is very hot and blue-tinged, reinforcing the Teff interpretation. In other words, even though the star is extremely distant, its light is dominated by a hot, blue-white surface, a candle burning brightly in the galactic halo or outer disk.
Sky Location and What the Data Tell Us
The star lies at right ascension roughly 15.45 degrees and declination about −72.50 degrees. In practical terms, that places it in the southern celestial hemisphere, well away from the northern winter constellations most skywatchers know. Such a position may be in a region of the sky populated by halo stars or distant outer-disk members. The Gaia data set that includes Gaia DR3 4687491332258331776 showcases how Gaia’s all-sky survey maps not just nearby suns, but also luminous beacons tucked far from the solar neighborhood.
What This Star Teaches Us About Temperature, Distance, and Light
The case of Gaia DR3 4687491332258331776 is a vivid reminder that temperature, size, and distance each tell a separate part of a star’s story. A surface temperature near 37,600 K is the fingerprint of a hot, early-type star. Its radius of about 6 solar radii signals a star that is not a diminutive dwarf, but an object with substantial surface area and energy output. When you combine those traits, the inferred luminosity lands in tens of thousands of solar luminosities, illustrating a true powerhouse blazing across the spiral arms or halo of our Milky Way.
“Light from the hottest stars travels far and fast, but Gaia’s fingerprints—temperature, radius, and distance—let us read that light as a map of our galaxy.”
Key Facts at a Glance
- Gaia DR3 ID: 4687491332258331776 (the star’s full Gaia DR3 name)
- Temperature: Teff_gspphot ≈ 37,563 K — blue-white and exceptionally hot
- Radius: radius_gspphot ≈ 5.96 R☉
- Distance: distance_gspphot ≈ 28,159 pc ≈ 92,000 light-years
- Brightness: phot_g_mean_mag ≈ 14.51 (not naked-eye visible; visible with telescopes)
- Color index: BP−RP ≈ +0.09 mag (blue-white color signature)
- Sky position: RA ≈ 15.45°, Dec ≈ −72.50° (southern celestial hemisphere)
- Notes: Radius_flame and mass_flame are NaN in this DR3 entry—detailed flame-based mass estimates aren’t provided for this source in DR3.
This distant blue-white star, Gaia DR3 4687491332258331776, exemplifies the kind of luminous beacon Gaia helps us map across the Milky Way. Its combination of extreme temperature, modest yet significant radius, and a location far beyond our solar neighborhood makes it a compelling target for future follow-up studies. While this article cannot claim a precise spectral classification beyond the hot, early-type nature suggested by Teff, the data points toward a young-ish, massive star that burns intensely and stands as a bright marker in the Milky Way’s outer reaches. The cosmos invites curiosity: how many such hot stars lie at the edge of our galaxy, quietly illuminating the halo with their blue glow?
This star, though unnamed in human records, is one among billions charted by ESA’s Gaia mission. Each article in this collection brings visibility to the silent majority of our galaxy — stars known only by their light.