A PAS­SION FOR SPACE

Dr Kim­berly En­nico on a plane-based ’scope.

Sky at Night Magazine - - CONTENTS - with Dr Kim­berly En­nico Dr Kim­berly En­nico is a mul­ti­dis­ci­plinary re­search as­tro­physi­cist at NASA and the SOPHIA mis­sion’s project sci­en­tist. For more in­for­ma­tion visit sofia.usra.edu

The world’s pre­mier fly­ing ob­ser­va­tory is un­rav­el­ling the mys­ter­ies of our Uni­verse by study­ing fun­da­men­tal pro­cesses af­fect­ing the for­ma­tion of stars, plan­ets and gal­ax­ies. SOFIA (the Strato­spheric Ob­ser­va­tory for In­frared As­tron­omy) fea­tures a Hub­ble-sized tele­scope in a mod­i­fied Boe­ing 747SP, fly­ing high into Earth’s strato­sphere (12km) to en­able us to study the in­frared Uni­verse.

But why in­frared? Over half of the ‘light we see’ in the Uni­verse is ra­di­a­tion that has been ab­sorbed by dust and re-emit­ted at in­frared wave­lengths. Much of the space be­tween stars is filled with atomic and molec­u­lar gas – mainly hy­dro­gen and he­lium – and tiny pieces of dust (solid par­ti­cles), com­posed of heav­ier el­e­ments like car­bon, oxy­gen and sil­i­con. By ob­serv­ing the in­frared light we are see­ing both the in­gre­di­ents for new stars – gas and dust – and left­over dust that has been cre­ated by both stel­lar birth and death.

Con­stantly cut­ting-edge

We still do not know how, when and where stars form. We have a rough idea but the va­ri­ety of star-form­ing re­gions seen to­day in­di­cates it is a com­pli­cated process. SOFIA em­ploys a suite of in­stru­ments to tackle the un­der­ly­ing trig­gers or in­hibitors of star for­ma­tion. By pe­ri­od­i­cally chang­ing its equip­ment SOFIA reaps the ben­e­fits of cut­ting-edge tech­nol­ogy.

For ex­am­ple, the GREAT (Ger­man RE­ceiver for As­tron­omy at Ter­a­hertz fre­quen­cies) spec­trom­e­ter is ideally suited to mea­sur­ing spec­tral lines in a va­ri­ety of star-form­ing en­vi­ron­ments. This im­proves our knowl­edge of how stars form at the ear­li­est stages, specif­i­cally by look­ing at gas in molec­u­lar clouds. With GREAT, we can ob­serve emis­sions from ionised car­bon and atomic oxy­gen to un­der­stand shocks, ther­mal con­di­tions and col­laps­ing mo­tions of gas that can form new stars.

Ad­di­tion­ally, GREAT hunts for small mol­e­cules called hy­drides, the ba­sic build­ing blocks of chem­i­cal path­ways in our Uni­verse, to probe the phys­i­cal con­di­tions in these clouds.

SOFIA’s new po­larime­ter, HAWC+ (Highres­o­lu­tion Air­borne Wide­band Cam­er­aplus), can map mag­netic fields on the scales of star-form­ing clouds and ‘snake-like’ fil­a­ments. Spin­ning dust grains aligned in the pres­ence of mag­netic fields emit po­larised light. HAWC+ de­tects this and de­rives the ge­om­e­try – and per­haps strength – of sur­round­ing mag­netic fields. We are on the verge of ob­ser­va­tional ev­i­dence that can tell us whether mag­netic fields help guide gas flow­ing onto fil­a­ments to a point where they be­come un­sta­ble and ini­ti­ate grav­i­ta­tional col­lapse to form stars, or if they pre­vent clouds from col­laps­ing to form stars. Is the Holy Grail of un­der­stand­ing star for­ma­tion within our reach?

Next year, a new spec­trom­e­ter called HIRMES (HIgh Res­o­lu­tion Mid-in­frarEd Spec­trom­e­ter) will study planet-form­ing sys­tems to in­form us how wa­ter is cre­ated, de­stroyed and even­tu­ally de­liv­ered to solid bod­ies. With each step in un­der­stand­ing how stars and plan­ets form, we get closer to un­der­stand­ing our Sun and Earth’s ori­gins.

This mar­vel of an air­plane-mounted tele­scope, un­af­fected by light tur­bu­lence, equipped with a high-tech in­stru­ment suite and able go wher­ever the sci­ence de­mands, brings new per­spec­tives in pur­suit of as­tron­omy’s most an­cient ques­tions.

Scope on a plane – SOFIA is housed in a Boe­ing 747SP

High-tech fly­ing ob­ser­va­tory SOFIA soars into the strato­sphere to peer into the Uni­verse in in­frared

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