Tom Geballe
NGC 2071 -IR:
A Who-dunnit Mystery
Two recently retired Gemini staff members (author Tom Geballe
and Dolores Walther) have utilized Gemini North to obtain the
sharpest composite infrared images ever of the chaotic core of one
of the nearest star-forming clouds. These images, combined with key
infrared spectral signatures of two of the embedded protostars, are
helping astronomers determine the causes of the mayhem.
Star formation can be a messy process. When gravity causes a portion of a calm interstellar
gas cloud to collapse, and a star is born, some of that infalling gas is violently blown back
into the surrounding cloud, disrupting much of it. In the process, small portions of the
cloud are briefly shock-heated to temperatures of thousands of degrees.
If only a single protostar at a time is engaged in this destructive activity, astronomers can
usually identify it. But when more than one protostar in a cloud is doing this at the same
time, understanding what is going on, including determining which protostars are respon-
sible for which parts of the disruption, is a challenge.
Such is the case with one of the nearest star-forming clouds to the Sun, NGC 2071. The
core of this cloud, known as NGC 2071-IR because of its bright infrared emission, has long
fascinated Dolores Walther, who retired in 2017 as head of Gemini North’s crew of Science
Operations Specialists.
Walther had always wanted to use Gemini and its powerful infrared instruments to get a
better look at NGC 2071-IR and solve some of its mysteries. I joined in the study and co-
published the results with her in the April 20, 2019, issue of The Astrophysical Journal.
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GeminiFocus
October 2019