the study about the properties of the gould belt keun-hong park seoul national university work shop...

The study about the prop-erties of the Gould Belt

Keun-Hong ParkSeoul National University

Work shop on Stars, Planets, and Life: Current Issues on Stellar AstronomyIn Honor of Professor Sang-Gak Lee’s Retirement


별과 우주 (Star & Universe) 1999, 11 월호


소백산천문대 (Sobaeksan Observatory), 2006

Contents

• Introduction• Targets• Result– Study 1: ISM– Study 2: Abundance

• Summary


Introduction

• What is the Gould Belt?– Discovered by Herschel and Gould– Ongoing star forming complex

• 1 kpc-sized flat structure• Inclined about 20° to Galactic Plane• Early-type stars, open clusters, YSOs…

• Several Survey Projects– JCMT Legacy Survey of the Gould Belt Project– The Spitzer survey of interstellar clouds in the Gould Belt– Herschel Gould Belt Survey Project


Introduction

• Similar structures are found in extra-galaxies.– M 83 (NGC 5236)– NGC 6946

• The origin of the Gould Belt is not clear.– The stellar feedback effect?– Impact of a high-velocity clouds?– Impact of a dark matter clump?

• Find the clues for the origin in this study


Introduction

• Select nearby young open clusters inside the Gould Belt and the Galactic Plane.

• Take the high resolution spectra of the stars in the clusters.– BOES at BOAO• R ~ 45,000

– UVES POP archive data• R ~ 80,000


Introduction

• Study 1: ISM–Measure E.W. of interstellar lines in the spectra of

early-type stars and derive column densities.– Find interstellar clouds and their distributions.– Improve our knowledge about the LISM.

• Study 2: Abundance– Derive the stellar atmospheric parameters– Derive the abundance from the metal lines.


Target

Name l (°) b (°) d (pc)

G.B Name l (°) b (°) d (pc)

G.B

Collinder 359 30 13 249 O Platias 6 205 -6 348 X

IC 4665 31 17 352 O Alessi 12 67 -12 537 X

Stephenson 1 67 16 390 O Roslund 5 71 0 389 X

ASCC 123 105 -4 250 O ASCC 23 168 14 600 X

Collinder 69 195 -12 400 O Stock 10 172 4 380 X

ASCC 21 200 -16 500 O NGC 2264 203 2 667 X

ASCC 20 202 -18 450 O Collinder 97 205 -2 630 X

ASCC 18 202 -18 500 O ASCC 104 55 -2 800 X

Collinder 70 205 -17 387 O


IC 2391 270 -7 175 O NGC 6475 356 -5 301 X

ISM

• Targets– IC 2391 – NGC 6475– Collinder 70– IC 4665, Collinder 359, Stephenson 1, Roslund 5

• Lines– Ti II (3383.76 Å)– Ca II (3933.66 Å)– Na I D (5889.95 Å, 5895.92 Å)– K I (7698.96 Å)


ISM


IC 2391

15km/s

ISM


IC 2391

15km/s23km/s

ISM


IC 2391 (~ 150 pc)

Ca II Na I

ISM


NGC 6475

-3 km/s

ISM


NGC 6475 (~300pc)

Ca II Na I

ISM


Collinder 70

25 km/s11 km/s

ISM


IC 4665, Collinder 359

-15 km/s

ISM


Stephenson 1, Roslund 5

-15 km/s

Abundance

• Almost observed target is early-type star.– A few metal lines -> detailed analysis is impossible– Consider non-LTE effect

• More study is needed in this part.

• Non-LTE effect is ignored in follow examples.


Star Cluster Mag.(V) Sp_Type Exp. (s)

HD 175538 Stephen-son 1 7.6 B9 3600 * 2

HD 191530 Roslund 5 7.9 B9II 3600 * 2

Abundance• T, gravity : H line profile fitting


star Hγ Hδ Hε Tlog g

HD17553

8

12750

4.25

HD19153

0

12500

3.75

Abundance• Mg


star Mg lines [X/H]

HD17553

8-0.50

HD19153

00.00

Abundance• Si


star Si lines [X/H]

HD17553

8-0.50

HD19153

00.00

Abundance• O


star O lines [X/H]

HD17553

80.25

HD19153

00.25

Summary

• Gould Belt is one of the most interesting structure• However, origin of it is not investigated.• Aim to find the clues of the origin from this study• Found the ISM clouds and their distributions from

the spectra of early-type spectra.• Try to derive the abundance of the stars in each clus-

ter, and to find the existence of the difference be-tween the Gould Belt members and non-members.


Thank You


the study about the properties of the gould belt keun-hong park seoul national university work shop...

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