Within the scope of the Hubble Space Telescope’s lens is Terzan 12, a radiant globular cluster that dominates this snapshot. These visuals are a part of a concerted effort to catalog globular clusters near our galaxy’s core, such as this one in Sagittarius. Because these clusters lie embedded within the dense gas and dust of the Milky Way, their starlight can be obscured or shifted in wavelength. This imagery is courtesy of ESA/Hubble & NASA, with acknowledgment to R. Cohen of Rutgers University.
The Hubble Space Telescope discloses the splendor of the globular cluster Terzan 12, highlighting the phenomenon where interstellar dust alters the light from stars, known as reddening. Adding to the intrigue, there is a historical mix-up with the naming of the Terzan clusters, especially the absent Terzan 11.
Terzan 12’s magnificent display, comprising an immense, dense collection of stars, is vividly captured by the NASA/ESA Hubble Space Telescope. Nestled within the Milky Way in Sagittarius, this globular cluster is veiled by gas and dust that modify its stellar emissions.
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Unveiling the Milky Way’s Core
These dazzling celestial counts are part of an observational sequence aiming to thoroughly investigate the scarce globular clusters at our galaxy’s heart, including Terzan 12, situated some 15,000 light-years away. While the Milky Way harbors approximately 150 known globular clusters, primarily in its peripheral halo, Hubble has transformed their examination since its deployment in 1990. Yet, the challenge of studying clusters like Terzan 12, heavily masked by cosmic dust, is the resultant reddening effect on their light.
The composite image presented shows Terzan 12’s position as observed by the Hubble Space Telescope.
Top: The Milky Way stretches across the constellation Sagittarius, with dense dust clouds carving through a pale backdrop of stars. The Rho Ophiuchi cloud complex can be spotted at the upper right.
Bottom left: A narrow field of the Milky Way, merely one degree wide. The globular cluster commands the center of the frame.
Bottom Right: Hubble’s latest image of Terzan 12, with intervening dust casting the starlight into various shades of red. The photo’s brightest red stars are expansive, mature giants, significantly larger than the Sun, and are foreground objects relative to the cluster. Only a select few may belong to the cluster. The brightest blue stars, suggesting youth and high temperature, are also foreground stars and not part of the cluster that comprises predominantly older stars. The cluster is estimated to be about 15,000 light-years from our planet.
Credits go to NASA, ESA, Stéphane Guisard, ESO, Digitized Sky Survey, ESA/Hubble, Roger Cohen (Rutgers University), and Joseph DePasquale (STScI).
The Reddening Effect
Interstellar clouds that intercept starlight can absorb and scatter the light, especially at shorter wavelengths. Consequently, blue light from stars is often obstructed, leaving the stars to appear redder. This scattering and absorption process is referred to as reddening and is evident in the diverse colors of this image. Stars less affected by dust shine in white and blue, while those enshrouded by dust display a menacing red tint. The denser the dust along our line of sight, the more pronounced the reddening effect on the starlight.
Earth’s Own Reddening
On Earth, we witness a similar phenomenon during sunsets, when atmospheric conditions scatter the shorter blue light waves, leaving the sun to bathe the sky in shades of red.
Stellar Color Diversity
Variations in color among the stars in this image are stark, with the brightest red ones being expansive, aged giants, dwarfing our Sun. These are located in the foreground, with only a handful potentially part of Terzan 12 itself. The most luminous blue stars, seeming to be young and hot, are also not within the cluster, as it is home to older stars.
Navigating Astronomical Challenges
Astronomers typically struggle with the reddening of stars, but the team studying Terzan 12 managed to mitigate this challenge by contrasting Hubble’s sharp new observations with pre-existing data. Their findings aim to enhance our understanding of the correlation between the age and composition of inner Milky Way globular clusters, paralleling the knowledge we have of the wider galactic clusters.
The Terzan Clusters’ Nomenclature Puzzle
Interestingly, there’s a longstanding confusion with the naming of the Terzan clusters due to a misidentification by astronomer Agop Terzan in 1971, leading to a missing “Terzan 11” in the sequence.
An Astronomical Quirk
Rediscovering lost celestial bodies is not unusual, even within our Solar System. Minor planets, asteroids, and dwarf planets often escape tracking due to limited observation data.
The Hubble Space Telescope is a symbol of international collaboration between ESA and NASA. The featured Hubble observations come from project #14074, led by R. Cohen.
Frequently Asked Questions (FAQs) about Terzan 12 Cluster
What is the significance of the Hubble Space Telescope’s image of Terzan 12?
The Hubble Space Telescope’s image of Terzan 12 provides a detailed view of a globular cluster that is heavily affected by interstellar reddening. This contributes to our understanding of celestial objects located in dust-rich areas of the Milky Way and the effects of interstellar dust on starlight.
Why does Terzan 12 appear red in Hubble’s images?
Terzan 12 appears red in Hubble’s images due to the reddening effect, where interstellar dust scatters and absorbs the blue wavelengths of the starlight more than the red wavelengths, causing the stars to look redder than they are.
What was the naming confusion with the Terzan clusters?
The naming confusion with the Terzan clusters arose when Agop Terzan mistakenly identified a previously discovered cluster as a new one, calling it Terzan 11. The error was never fully corrected, leading to an ongoing discrepancy in the naming sequence of the Terzan clusters.
How does Hubble’s observation of Terzan 12 contribute to astronomy?
Hubble’s observation of Terzan 12 aids astronomers in studying the properties of globular clusters near the galactic core, despite the challenges of interstellar dust, and improves our understanding of the relationship between the age and composition of these clusters.
Can the reddening effect observed in space also be seen on Earth?
Yes, a similar reddening effect can be observed on Earth, particularly during sunsets when the atmosphere scatters the shorter blue wavelengths of sunlight, leaving the longer red wavelengths to dominate, which gives the sky its reddish hue.
More about Terzan 12 Cluster
- Hubble Space Telescope Overview
- Understanding Globular Clusters
- Astronomical Reddening Explained
- The Mystery of Missing Globular Clusters
- ESA Hubble Science Archive
5 comments
theres a typo in the second paragraph where they spell ‘light’ as ‘ight’, editors should’ve caught that before publishing
interesting about the reddening of stars i always wondered why some stars appear redder in the sky, the more you know huh
i read about that naming mix up with Terzan clusters before funny how these things stick even in science
sometimes I forget how big space is, 150 globular clusters just in our galaxy alone thats wild
gotta say its pretty amazing what Hubble is still doing after all these years seeing clusters like Terzan 12 despite all that cosmic dust