New Instrument Will Join Study of Exoplanets

SOCORRO, N.M. April 26, 2012 – New Mexico Tech professors and students are making headway in the burgeoning field of exoplanet study. Now, three years after initial funding, the Tech team has completed the  final design review and is in the midst of the construction of NESSI.

Dr. Michelle Creech-Eakman(right) shows the K mirror to engineer Fernando Santoro and grad student Heather Bloemhard.

A rendering of the handling cart that will house the New Mexico Exoplanet Spectroscopy Survey Instrument.

The New Mexico Exoplanet Spectroscopic Survey Instrument, known as NESSI, is a project that partners Tech astrophysicists and instrumentation experts with scientists at the Jet Propulsion Laboratory in California. Together, they are building a new instrument that will be able to gather data on planets orbiting distant stars in order to characterize their atmospheres.

The mounts and structures are under construction. Most of the optics – more than two dozen made-to-order optics – are completed. Dr. Michelle Creech-Eakman said she and other physics professors have submitted a proposal to the National Science Foundation to fund a crucial part, a $350,000 cryogenic array detector that will be the brains of the instrument.

“The exoplanet community is changing on a less-than-two-year time scale,” said Creech-Eakman, a lead scientist on the project and project scientist of the Magdalena Ridge Observatory Interferometer. “The Kepler Exoplanet portfolio has more than 2,000 candidates and we’re finding new ones every week. There are a lot of new ideas and it’s really frenetic.”

Dr. Pieter Deroo of the Jet Propulsion Lab and the Exospec team visited Tech for several days in early April to consult with Creech-Eakman and graduate student Heather Bloemhard. Deroo also presented a seminar about FINESSE, a space-based telescope led by Dr. Mark Swain of JPL, which will be purpose built for characterizing and imaging exoplanets. Deroo said FINESSE, which stands for Fast Infrared Exoplanet Spectroscopy Survey Explorer, if selected for Phase B by NASA, will  be launched in 2016.

Exoplanet research captures the imagination of non-scientists. Ultimately, astrophysicists are looking for planets that could sustain life. News about discoveries  swirls through the popular press these days. The planet known as GJ1214b was widespread news beginning February 21 after the Hubble Space Telescope returned data and images. That extrasolar planet – or exoplanet – has a diameter roughly 2.7 times that of Earth and a surface temperature of about 450 degrees Fahrenheit. Bob Petz, writing for Ecology.com, wrote this about GJ1214b: “Just when exoplanets became too numerous to bother counting, astrophysicists have discovered a new type of extrasolar planet — a steamy waterworld shrouded in a thick atmosphere.”

Scientific American reported February 27 about an academic team that is investigating and characterizing another distant planet – HD 189733b, which is orbiting a gas giant just 60 light-years away.

Space.com published an article on February 29 about global efforts to examine exoplanets. That article later appeared on the popular Huffington Post website.

“We want to get NESSI finished because the science is moving so quickly,” Creech-Eakman said. “Other observatories are looking at exoplanets, but they aren’t optimized for this mission. Hopefully, we’ll have a unique niche in the field.”

NESSI is basically a super high-tech near-infrared spectrographic camera attached to the 2.4-meter telescope at the Magdalena Ridge Observatory.

Near-infrared light from outer space is collected through the telescopes optics and funneled into NESSI’s series of specialized optics. Light – visible and infrared – will pass through a grating prism – or grism – and several filters, and finally be collected by an infrared array.

“NESSI isn’t about imaging. It’s about spectroscopy,” she said. “But it’s been designed so well, that if we take out the grisms, we can get good wide-field imaging too. We will have a lot of different things we can do with this instrument.”

A science-grade infrared array cost more than $350,000 – and is the size of a postage stamp. Those arrays are built by Teledyne. The instrument also includes a cryogenic Dewar, developed by Universal Cryogenics in Tucson, which will keep the instrument’s guts super-cooled with liquid nitrogen. In all, the instrument will include more than two dozen optics – all to provide scientists with data that allow them to tell the world more about newly found planets.

Fernando Santoro and the mechanical engineering team at the Magdalena Ridge Observatory designed the framework for the instrument, which is being fabricated at two shops in Albuquerque and Bosque Farms. Santoro is presenting his research at the SPIE Conference this summer.

The multi-million dollar project completed final design review with the Jet Propulsion Laboratory collaborators in July 2011 and will be fully assembled this fall..

While the search for exoplanets has grown exponentially in recent years, Creech-Eakman envisions the field moving toward the characterization and imaging of these distant planets.

“I have a sense the field will move on from discovery into spectroscopy,” she said. “The characterization and imaging – that’s the next wave.”

Creech-Eakman and Dr. Penny Boston, professor of Earth science at Tech, are hosting a three-day workshop on exoplanets near Socorro in May. They are bringing together physicists, biologists, volcanologists and science fiction writers to discuss the future of the discipline.

“We want to discuss where to take the field from here, what should our focus be over the next decade?” she said. “How can we position ourselves to advance the study of exoplanets? And what questions do we need to be asking about our data and volcanism and life?”

Several students have participated in the NESSI project over the past three years. Dr. Colby Jurgenson, instrument specialist at the MRO, started as a post-doc and has overseen the optical design process. Heather Bloemhard is in charge of the optics tolerancing and optics contracts. Dr. Michael Hrynevych, a post-doc researcher, is a systems engineer and has experience putting instruments on telescopes from his time at Keck Observatory.

Bloemhard is among a growing number of scientists who are devoting their academic career to the study of these strange far-off worlds.

“I like the opportunity for variety that exoplanets present,” she said. “The field is so new and moving so quickly that the possibilities for what I can do next are … well, vast.”

Bloemhard earned a bachelor’s  degree from George Mason University in Virginia, double majoring in astronomy and physics. She then began looking for a graduate program.

“Toward the end of my bachelor’s studies, I started studying atmospheric physics to fill my schedule,” she said. “I tried to pick a school with good programs in both atmospheric physics and astrophysics because I was uncertain about which track to pursue. Luckily I found New Mexico Tech, which has great programs in both.”

Soon after arriving in Socorro, she joined the Magdalena Ridge Observatory Interferometer team as a summer intern and developed an appetite for instrumentation. Now, she is a graduate research assistant for the NESSI project, responsible for oversight of optics.

For her dissertation, Bloemhard is characterizing three “Hot Jupiters,” large gaseous planets that orbit very close to their stars. Using data collected via the spectrograph at NASA’s Infrared Telescope Facility in Hawaii, she is developing a profile about these planets that seem to defy conventional wisdom about how planets should behave.

Once NESSI goes online, scientists like Bloemhard and Creech-Eakman will have a valuable new tool in their arsenal in the quest to learn more about exoplanets – and life on other planets. In the meantime, scientists must employ cumbersome and time-consuming data-reduction methods to cajole conclusions out of their observations.

Deroo, in his presentation at Tech, said that current instruments aren’t designed for watching exoplanets. He and his colleagues have to “decorrelate” data – essentially subtract infrared data from the distant stars from their combined light spectra to distill their collected information down to the data points that help them characterize the atmospheres of the distant planets.

The FINESSE space-based telescope will be dedicated to a two-year mission to look at 200 exoplanets of three different types – no earlier than 2016. The New Mexico Tech instrument will be a ground-based telescope doing the same thing – hopefully beginning in 2013.

For Bloemhard, who expects to finish her doctoral studies in 2013, NESSI probably won’t be online soon enough for her to gather data for her dissertation. For the next crop of astrophysics students – and astrochemists and astrobiologists and geologists – NESSI will provide opportunities found nowhere else.

– NMT –

By Thomas Guengerich/New Mexico Tech