This Six-Minute Satellite Studies Star Nurseries

By Andrew Tarantola on at

Not every scientific exploration of the cosmos requires a multi-year, multi-billion dollar effort like the Hubble Space Telescope. In fact, sometimes all it requires is a reusable rocket, an ultraviolet camera, and six minutes in space.

Built by a team of researchers from the University of Colorado at Boulder and dubbed the Colorado High-resolution Echelle Stellar Spectrograph (CHESS), this short-lived scientific experiment seeks to study the light from nearby stars while in space—light that is otherwise blocked by Earth's atmosphere. This is why the system has been mounted into a Black Brant IX suborbital sounding rocket and launched from the White Sands Missile Range in New Mexico late last week.

See, as this light travels through the voids of interstellar space it interacts with elementary particles, which can block certain wavelengths from reach Earth. By studying which wavelengths are missing, they can infer what sorts of particles the light has passed through on its way to us.

"These atoms are the raw materials, the very building blocks for the next generation of stars and planets," said Kevin France at the University of Colorado at Boulder. "We're making detailed measurements of how many atoms have transitioned into molecules, which is the very first step toward star formation."

To do this, the CHESS leverages a powerful spectograph: an instrument designed to parse and measure the various wavelengths of UV light that it sees. As the Boulder team's mission abstract clarifies:

Spectroscopic systems capable of delivering high resolution with low backgrounds will be essential to addressing these topics. Towards this end, we are developing a rocket-borne instrument that will serve as a pathfinder for future high-sensitivity, highresolution UV spectrographs. The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) will provide 2 km s-1 velocity resolution (R = 150,000) over the 100 - 160 nm bandpass that includes key atomic and molecular spectral diagnostics for the intergalactic medium (H I Lyman-series, O VI, N V, and C IV), exoplanetary atmospheres (H I Lyman-alpha, O I, and C II), and protoplanetary disks (H2 and CO electronic band systems). CHESS uses a novel mechanical collimator comprised of an array of 10 mm x 10 mm stainless steel tubes to feed a low-scatter, 69 grooves mm-1 echelle grating. The cross-disperser is a holographically ruled toroid, with 351 grooves mm-1. The spectral orders can be recorded with either a 40 mm cross-strip microchannel plate detector or a 3.5k x 3.5k δ-doped CCD. The microchannel plate will deliver 30 μm spatial resolution and employs new 64 amp/axis electronics to accommodate high count rate observations of local OB stars.

What the science-speak above means is that the CHESS spectrograph is so powerful that it not only can tell what kinds of particles are present but how fast they're moving and the amount of turbulence in the larger gas clouds. This in turn indicates the general age and density of the gas cloud.

"Carbon, for example, will appear differently over time," France said in a press release. "Early on the cloud will have carbon with a missing electron, called ionised carbon. As the gas gets denser, the carbon atoms gain back their electrons, so you have neutral carbon. As you get even denser clouds, the carbon binds to oxygen creating carbon monoxide molecules – and at that point you can probe the cloud conditions that precede the collapse into a star."

The May 24th launch reportedly went swimmingly and the Boulder team is currently digging through the gathered data. The team hopes to repeat their success with other, similar suborbital experiments in the coming months and years. [NASA - Spied Digital Library]