Birth of Stars,

Near and Far

Dr. Solange Ramírez (Caltech/IPAC)

Dr. Steven Finkelstein (University of Texas at Austin)

Dr. Bryan Méndez (University of California, Berkeley)

Facilitator: Dr. Emma Marcucci (STScI)

Science Briefing

May 3, 2018

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Lagoon Nebula

Zoom and Pan: http://hubblesite.org/video/1031/news_release/2018-21

Image Credit: NASA/ESA/STScI

Additional Resources

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http://nasawavelength.org/list/2146Hubble’s 28th Anniversary

Lagoon Nebula: Stellar Nursery

Lagoon Nebula Images

Lagoon Nebula Videos

Celebrity Video:

Think Tank: A Star is Born

Images / Lithos and Activities:

NGC 2174: Monkey Head Nebula and Star Formation Activity

Stellar Spire in the Eagle Nebula

Star Birth: Cool Cosmos

Milky Way: Cool Cosmos

Additional Nearby Star Formation resources

Progressive Star Formation in the Magellanic Clouds

Hubble Survey Unlocks Clues to Star Birth in Neighboring Galaxy

Firestorm of Star Birth in Galaxy M33

http://nasawavelength.org/list/2142Additional list curated by Dr. Bryan Méndez:

Outline of this Science Briefing

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1. Solange Ramírez (Caltech/IPAC)

Nearby Star Formation: Understanding Star Formation in the Milky Way

2. Steven Finkelstein (University of Texas at Austin)

Distant Star Formation: Star Formation in the Early Universe

3. Bryan Méndez (University of California, Berkeley)

Highlight of Resources to Engage Audiences

4. Discussion / Questions

Star Formation in the Milky Way

Solange V. Ramirez(Caltech/IPAC)

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Where do stars form ?

• Molecular clouds are part of the Interstellar Medium

• Star formation starts with the collapse of a molecular cloud, due to gravity

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Visible and Infrared Light

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Infrared light has the ability to “see” through opaque molecular clouds

How do stars form ?

• More material will be accreted until the collapse is stopped

• The material of the disk will form planets

• The cores will form a proto-star and a disk

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Star Forming Core

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Cores are hidden in the visible, they are cold, and

they emit most of their light in the infrared

Star Forming Outflow

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Outflows appear as a core collapses

Protostar

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Outflow dissipates

Disk is present

Star starts to ignite

Star with Disk

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Star light has been blocked in these images, revealing a debris disk

Planets may be formed from the material from the debris disk

How is the collapse stopped ?

• Gravity goes inwards

• A star is born when it starts radiating

• Radiation pressure goes outwards

• The equilibrium between gravity and pressure stops the collapse

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What makes a star shine ?

NUCLEAR FUSION

1H + 1H 1He + Radiation (light)

The core of the star is hot enough to become a natural nuclear reactor !

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Where do stars form ?

• The collapse may be inhomogeneous and form filamentary structures

• Cores of material will evolve to form stars

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Where do stars form ?

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Stars can form in groups!

The Orion Nebula is a giant stellar nursery, where thousands of stars are being born.

The Milky Way: our Galaxy

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The Milky Way is a spiral galaxy

This is a scientifically based artist concept of the Milky Way

Most star forming clouds are in Spiral Arms in the Milky Way

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Star formation in external galaxies: 30 Dor in the LMC

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S T A R F O R M A T I O N I N

T H E E A R L Y U N I V E R S E

S T E V E N F I N K E L S T E I NT H E U N I V E R S I T Y O F T E X A S A T A U S T I N

N A S A ’ S U N I V E R S E O F L E A R N I N G M A Y 3 R D , 2 0 1 8

W H A T I S A G A L A X Y ?

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G A L A X I E S I N T H E E A R L Y U N I V E R S E

L O O K V E R Y D I F F E R E N T

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U N D E R S T A N D I N G T H I S P R O C E S S I S O N E

O F T H E M A I N G O A L S O F M Y R E S E A R C H

???

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D E T E C T I N G S T A R - F O R M A T I O N

• When new stars form, they form at all masses, distributed according to the “initial

mass function”, which observations show produces many more low-mass stars

than high-mass stars.

• However, high-mass stars are so much brighter than low-mass stars that they

outshine them.

• They also have very short lifetimes, so if you see UV emission from a massive

star, it means it has just formed, and you have discovered ongoing star-

formation activity.

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G A L A X I E S W H I C H A R E F O R M I N G S T A R S H A V E

S P E C T R A L I K E H I G H - M A S S S T A R S

UltravioletOptical

Infrared

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T H E A N D R O M E D A G A L A X Y

Ultraviolet

Optical

Infrared

M A S S I V E ,

N E W L Y F O R M E D

S T A R S

L O W E R - M A S S ,

O L D E R S T A R S

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T O S E E T H I S I N T H E D I S T A N T U N I V E R S E , T H E E X P A N D I N G

U N I V E R S E M E A N S T H A T W E H A V E T O L O O K I N T H E

O P T I C A L ( A N D E V E N T U A L L Y , I N T H E N E A R - I N F R A R E D )

E D W I N H U B B L E

( 1 8 8 9 - 1 9 5 3 )

Redshift

(z)

Ultraviolet

Wavelength

(nm)

Time since

Big Bang(billions of

years)

0 150 13.8

1 300 6

2 450 3

4 750 1.5

6 1050 0.9

8 1350 0.7

10 1650 0.5

12 1950 0.3

Hu

bb

le’s

Wh

eelh

ou

se

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E V O L U T I O N O F S T A R F O R M A T I O N W I T H

C O S M I C T I M E

• This plot shows the evolution of the “cosmic star-formation rate density”.

This is the amount of star-formation, per unit volume, measured in solar

masses per year - it can be thought of as how many stars of a mass like the

Sun form per year.

• As you can imagine, this requires some of the deepest imaging imaginable - this

plot comes from a paper by Piero Madau using the original Hubble Deep Field.

Madau 1996

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M O V I N G T O H I G H E R R E D S H I F T W I T H H U B B L E

• New deep fields, first the Hubble Ultra Deep field, done with

the newer visible-light Advanced Camera for Surveys, then

the near-infrared version, done with the Wide-Field Camera

3, allowed these studies to be pushed to z ~ 10.

Finkelstein 201629

B R E A K I N G T H E R E D S H I F T 1 0 B A R R I E R

• To move to even higher redshift requires a telescope

which is sensitive to even redder wavelengths than

Hubble, which is one of the primary science drivers for the

James Webb Space Telescope.

Redshift

(z)

Ultraviolet

Wavelength

(nm)

Time since

Big Bang(billions of

years)

2 450 3

4 750 1.5

6 1050 0.9

8 1350 0.7

10 1650 0.5

12 1950 0.35

15 2400 0.25

Hu

bb

le’s

Wh

eelh

ou

se

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C O N C L U S I O N S

• We can trace star-formation activity by looking for ultraviolet

emission from bright, high-mass stars. They are short lived, so

their presence indicates ongoing star formation.

• To observe this in the distant universe, we must observe redshifted

ultraviolet emission, which exists in the optical for modest redshifts,

and in the infrared for the most distant galaxies known.

• Through these observations, we have found that star-formation

activity rose at a slow-but-steady level from early times, peaking

around 10 billion years into the past. This activity has since been

decreasing at a fast clip, such that the star-formation rate density

today is similar to that at a time when the universe was less than

one billion years old.

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Star FormationEducational Resources

Dr. Bryan Mendez, UC Berkeley@bryanjmendez

NASA Wavelength

33@bryanjmendez

Images: NASA Website

34@bryanjmendez

Images: HUBBLESITE

35@bryanjmendez

Images: AstroPix

36@bryanjmendez

Images: WISE

37@bryanjmendez

Images: OWN

38@bryanjmendez

Observe

39@bryanjmendez

Elaborate

40@bryanjmendez

Elaborate

41@bryanjmendez

ASTC partnership

A Professional Development opportunity –

How to Use NASA Resources;

future funding resources available

• Seven webinars were held in 2018, with these goals:o Improve familiarity of NASA Astrophysics resources and ways to use themo Increase knowledge of NASA Astrophysics-related conceptso Utilize real NASA datao Interact with NASA Subject Matter Experts

• Webinars are archived for viewing in the NASA’s Universe of Learning Community of Practice space, http://community.astc.org/communities/community-home?CommunityKey=1255165e-7b78-4791-8fcf-3eccfc52500b

As a follow-on to this webinar series, there will be an opportunity to apply for $2,500 mini-fund resources to be competitively awarded to selected institutions, in order to implement or facilitate programming, produce exhibits, etc., using Universe of Learning resources.

Applications open May 9, 2018 and are due June 4, 2018.

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To ensure we meet the needs of the education community (you!), NASA’s UoL is committed to performing regular evaluations, to determine the effectiveness of Professional Learning opportunities like the Science Briefings.

If you prefer not to participate in the evaluation process, you can opt out by contactingKay Ferrari <kay.a.ferrari@jpl.nasa.gov>.

This product is based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Jet Propulsion Laboratory, Smithsonian Astrophysical Observatory, and Sonoma State University. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration.

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