1. Hubble Science Briefing The “Monkey’s Tooth?” Hubble’s new infrared view of a star-forming pillar 1 April 3, 2014 Zolt Levay ・ Hubble Heritage STScI

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3. NGC 2174 Hubble’s 24 th Anniversary  Choosing the target  Context, nomenclature  Observation planning  Observation timeline  Data  Image features 3

4. Yurij Tukachev Hubble’s Hidden Treasures 4 WFPC2 2001

5. Location on the sky 5

6. 6 Zoom in to NGC 2174 Digitized Sky Survey red+blue

7. 7 Star-forming cloud NGC 2174 NGC 2175 Open (galactic) cluster NGC 2174 HII (ionized) region Digitized Sky Survey red+blue SH 2-252

8. The monkey head? 8 Photo: J-P Metsavainio

9. The monkey head? 9

10. The monkey’s tooth? 10

11. Visible — WFPC2 — 2001 11

12. Infrared — WFC3 — 2014 12

13. Visible vs. IR 13

14. Observation planning 14  Orbits  Pointing/mosaic  Instruments, filters  Exposure time

15. Observation planning — pointing 15 WFC3/IR ACS/WFC parallel Astronomer’s Proposal Tool (APT), Aladin Digitized Sky Survey (DSS) image 2x2 mosaic

16. Observation planning — filters 16

17. Observation planning — visibility 17 Astronomer’s Proposal Tool (APT)

18. Observation planning — orbit 18 Astronomer’s Proposal Tool (APT)

19. Data — first visits 19

20. Data — F105W mosaic 20

21. Data — replacement visits 21

22. Data — replacement tiles 22

23. Data — mosaics 23

24. Apply color 24

25. 25 Color composite

26. 26  Name: NGC 2174-75, Monkey Head Nebula, Sharpless 2-252 (refers to larger nebula)  Constellation: Orion  Coordinates: R.A. 06 h 09 m 10 s, Dec. +20° 27 ′ 20 ″  Distance: 6,400 light-years, 2 kiloparsecs (~5x M42)  Instrument: HST WFC3/IR  Observation date: February 7-24, 2014  Wavelength: 1,050-1,600 nm (1.05-1.60 μ m)  Exposure: 25-35 min./filter/pointing Factoids

27. Image features — detail 27

28. Image features — detail 28

29. Image features 29

30. 30 Distinctive features in the image Many more stars are apparent in the IR Several small knots (red markers) are seen completely or nearly separated from the main body of the pillar feature. As the gas and dust are eroded and evaporated from the nebula, denser areas remain as islands, some of which may have enough density to collapse into stars. At the top of one of the sub-pillars there appears to be a proto-stellar jet (yellow marker), the signature of early star formation. Jets appear in many star-forming regions such as this, sometimes apparent in visible light, sometimes only appearing in the IR. Higher resolution (JWST) imaging or spectroscopy would be needed to confirm that this is a jet. Many galaxies (green markers) appear in the IR image, which are totally obscured in visible light. We can conclude that this region of space is much more transparent at infrared wavelengths. Filaments of gas (blue markers) appear to be streaming from the surface of the denser portion of the pillar. The hot stars sculpting the material are heating and evaporating the gas and dust at the surface, and this material is moving away from the denser material, possibly under the influence of magnetic fields.

31. 31 Hubble Heritage Zolt Levay Carol Christian Lisa Frattare Mario Livio Jennifer Mack Max Mutchler Shelly Meyett Keith Noll Josh Sokol