Editing Eta Carinae (section)

===Infrared===
[[File:Stars similar to Eta Carinae in nearby galaxies.jpg|thumb|upright=1.2|alt=Array of images of ten stars similar to η&nbsp;Carinae in nearby galaxies|Stars similar to η&nbsp;Carinae in nearby galaxies]]
Infrared observations of η&nbsp;Carinae have become increasingly important. The vast majority of the electromagnetic radiation from the central stars is absorbed by surrounding dust, then emitted as [[mid-infrared|mid-]] and [[far infrared]] appropriate to the temperature of the dust. This allows almost the entire energy output of the system to be observed at wavelengths that are not strongly affected by [[Extinction (astronomy)|interstellar extinction]], leading to estimates of the luminosity that are more accurate than for other [[List of most luminous stars|extremely luminous stars]]. η&nbsp;Carinae is the brightest source in the night sky at mid-infrared wavelengths.<ref name="mehner2014">{{cite journal|bibcode=2014A&A...564A..14M|title=Near-infrared evidence for a sudden temperature increase in Eta Carinae|journal=Astronomy & Astrophysics|volume=564|pages=A14 |last1=Mehner|first1=Andrea|last2=Ishibashi|first2=Kazunori|last3=Whitelock|first3=Patricia|last4=Nagayama|first4=Takahiro|last5=Feast|first5=Michael|last6=van Wyk |first6=Francois|last7=de Wit|first7=Willem-Jan|year=2014|doi=10.1051/0004-6361/201322729|arxiv = 1401.4999|s2cid=119228664}}</ref>

Far infrared observations show a large mass of dust at 100–150 K, suggesting a total mass for the Homunculus of 20 [[solar mass]]es ({{solar mass}}) or more. This is much larger than previous estimates, and is all thought to have been ejected in a few years during the Great Eruption.<ref name="impostors"/>

[[Near-infrared]] observations can penetrate the dust at high resolution to observe features that are completely obscured at visual wavelengths, although not the central stars themselves. The central region of the Homunculus contains a smaller ''Little Homunculus'' from the 1890 eruption, a ''butterfly'' of separate clumps and filaments from the two eruptions, and an elongated stellar wind region.<ref name="artigau">{{cite journal|doi=10.1088/0004-6256/141/6/202 |title=Penetrating the Homunculus – near-infrared adaptive optics images of Eta Carinae |journal=[[The Astronomical Journal]] |volume=141 |issue=6|page=202 |year=2011 |last1=Artigau |first1=Étienne |last2=Martin |first2=John C. |last3=Humphreys |first3=Roberta M. |last4=Davidson |first4=Kris |last5=Chesneau |first5=Olivier|last6=Smith |first6=Nathan|bibcode=2011AJ....141..202A|arxiv = 1103.4671 |s2cid=119242683}}</ref>