Hubble Heritage Archive · Star cluster
Trumpler 14: Hubble's View of a Half-Million-Year-Old Star Cluster
Only half a million years old, packed with blue-white giants that will explode within a few million more, and carving the cloud that made them.
Trumpler 14 is a newborn by the standards of star clusters. At about 500,000 years old it is a hundredth of a percent of the age of the Sun, and it has had no time to lose its heaviest members. That is why it holds one of the densest gatherings of massive, luminous stars anywhere in the Milky Way, close to the center of the Carina Nebula.
The cluster lies about 8,000 light-years away. In the Hubble picture its brightest stars blaze blue-white with long diffraction spikes, the cross-shaped rays that Hubble's optics add to every bright point of light. The spikes come from the four thin supports that hold the telescope's secondary mirror in place, which diffract the light of each bright star into a cross. They are a property of the telescope, so every bright star in the frame carries the same pattern at the same angle. Behind and around them are the clouds of the nebula, tinted blue and brown by gas and dust.
Bright now, gone soon
Massive stars burn their hydrogen fuel at a ferocious rate. The blue-white giants of Trumpler 14 are expected to exhaust it and explode as supernovae within just a few million years. Their winds already push on the surrounding gas, and the blast waves of those supernovae will carve deeper cavities into nearby clouds of gas and dust.
Those same forces compress the clouds as they hollow them out, which can start a new generation of stars. With a mass of more than 4,300 times that of the Sun, Trumpler 14 is responsible for many of the dark globules and elephant-trunk columns in its part of the nebula, structures in which young stars are now forming. The protostar IRAS 20324+4057 in Cygnus shows the same process close up, around a different group of hot stars.
The small dark knot
Left of center in the image, a tiny black shape stands out against the bright background. It is a small clump of gas mixed with dust, dense enough to block the light behind it and seen in silhouette.
Knots like this are the leftovers of the cloud from which the cluster formed. Exposed to the radiation of the stars around it, the nodule is being eroded from the outside, and its sharp outline is a measure of how dense it still is.
| Name | Trumpler 14 |
|---|---|
| Type | Open cluster in the Carina Nebula |
| Constellation | Carina |
| Distance | About 8,000 light-years (2,450 parsecs) |
| Age | About 500,000 years |
| Position (J2000) | R.A. 10h 43m 55.92s, Dec. −59° 32′ 60.00″ |
| Camera | Advanced Camera for Surveys, Wide Field Channel |
|---|---|
| Observed | July 17, 2005 and July 29, 2006 |
| Programs | HST proposals 10241 and 10602 |
| Released | January 21, 2016 |
How the picture was made
The image combines Advanced Camera for Surveys exposures taken on July 17, 2005 and July 29, 2006. They came from two research programs, proposal 10241 and proposal 10602, the second led by Jesús Maíz Apellániz. Four filters were used. Three broad or medium bands record the starlight from blue to near-infrared, and a narrowband filter isolates the red glow of hydrogen and ionized nitrogen in the gas around the cluster.
Hubble filter names encode their shape. W stands for wide, M for medium and N for narrow, while LP marks a long-pass filter that lets through everything redder than its cut-off wavelength. The number gives the approximate central or cut-off wavelength in nanometers, so F658N is a narrow band near 658 nanometers that takes in hydrogen-alpha and the neighboring line of ionized nitrogen. F850LP, by contrast, starts at 850 nanometers and runs to the red limit of the camera.
| Filter | What it records | Shown as |
|---|---|---|
| F435W (B) | Blue starlight near 435 nanometers | Blue |
| F550M (V) | Visible light in a medium-width band near 550 nanometers | Green |
| F658N | Hydrogen-alpha and ionized nitrogen [N II] from the surrounding gas | Red |
| F850LP (z) | Near-infrared light beyond 850 nanometers | Purple |
The four-color assignment is unusual. Most Hubble color pictures use three hues, but here the near-infrared F850LP frame was shown in purple, a fourth color added on top of blue, green and red. That lets the hydrogen glow keep the red channel while the reddest starlight still contributes. Are the Colors Real? explains how grayscale exposures like these are toned and combined. The picture was released on January 21, 2016.
Finding Trumpler 14 in the wider nebula
The cluster is a small part of a much larger scene. In the 2007 Hubble mosaic of the Carina Nebula, which spans about 50 light-years, Trumpler 14 is one of the bright knots of stars in the central region, with Eta Carinae far to the left.
That mosaic was made mostly in the light of hydrogen, so the cluster's stars appear as bright points, while the 2016 picture of the cluster itself shows their colors. Together the two images trace the same region at two scales.
Questions readers ask
How old is Trumpler 14?
About 500,000 years, which makes it one of the youngest open clusters known. Its age explains its brilliance: the most massive stars, which burn out first, are still shining. Within a few million years many of them are expected to explode as supernovae.
How far away is Trumpler 14?
It is about 8,000 light-years away, inside the Carina Nebula in the southern constellation Carina. The nebula as a whole is usually given a distance of about 7,500 light-years, and the two figures are close enough to describe the same region.
What is the black spot in the Trumpler 14 image?
It is a small nodule of gas mixed with dust, dense enough to block the light behind it. It sits left of the cluster's center and appears as a dark silhouette against the glowing gas. Clumps like it are remnants of the cloud that formed the cluster.
Why are there four colors in the image?
The picture used four filters. Blue, green and red were assigned to a blue filter, a visible-light filter and a hydrogen-alpha filter, and a near-infrared filter was added in purple. The extra color keeps the hydrogen glow distinct while including the reddest starlight.