A comet bright­ens the hol­i­day sky over North­ern New Mex­ico

The Taos News - - VALLE VISTA - By Gary Zien­tara Mount San­gre Ob­ser­va­tory

Each year, dozens of comets come close enough to Earth to be de­tected by te­le­scopes.

A few can be seen through binoc­u­lars. But rarely any can be seen us­ing just your own eyes.

Comet Wir­ta­nen (WERE­tan-EN) may be one of those rare comets vis­i­ble to the naked eye. As of the be­gin­ning of Thanks­giv­ing week, Comet Wir­ta­nen has bright­ened to mag­ni­tude 5, still too dim to see with­out binoc­u­lars. But this comet con­tin­ues to get closer to the Earth and to the Sun at the same time. Its clos­est ap­proach to us (about 7 mil­lion miles) co­in­cides with its clos­est ap­proach to the sun (per­i­he­lion).

This vir­tu­ally as­sures that this comet will shine at least five times brighter than it does now. That dra­matic bright­en­ing be­gan on Dec. 1 and reached its max­i­mum Dec. 16. Right now, the full moon’s glare may wash out the much dim­mer comet.

The nu­cleus of Comet Wir­ta­nen is only .75 miles in di­am­e­ter. How­ever, it is com­posed of lots of dirty snowy ice and volatile gasses that, when heated by the sun, will form a fog (coma) around it, ex­tend­ing thou­sands of miles from its sur­face. In­cluded in the coma is C2 or di­atomic car­bon, which glows green when ex­posed to sun­light.

Some “ex­perts” say that the green glow is from CN or cyanogen gas, but CN glows pur­ple when ex­posed to the sun’s ra­di­a­tion. I in­tend to take the spec­trum of Comet Wir­ta­nen us­ing the dif­frac­tion gra­di­ent fil­ter on the Mount San­gre Ob­ser­va­tory tele­scope to de­tect the gasses in Wir­ta­nen’s coma. I hope to pub­lish the re­sults in the Jan­uary 2019 is­sue of the Uni­verse from Mount San­gre Ob­ser­va­tory mountsan­gre­ob­ser­va­tory.com.

Comet Wir­ta­nen (cat­a­logued as 46P/Wir­ta­nen) is a short-pe­riod comet dis­cov­ered in 1948. It or­bits the sun once ev­ery 5.4 years. It be­longs to a fam­ily of comets that have had their or­bits dras­ti­cally changed by the grav­i­ta­tional in­flu­ence of planet Jupiter.

Gary Zein­tara

Mon­key Head Ne­bula 6,300 light years away in the con­stel­la­tion Orion The Hunter as seen from the Mount San­gre Ob­ser­va­tory near An­gel Fire.

Gary Zein­tara

Comet 46P Wir­ta­nen as seen from a tele­scope in An­gel Fire.

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