X線で探る星形成坪井陽子
中央大学理工学部

X線天文とはWhat can we learn using X-rays? (I)X-Rays: Probing Deep Universe!!

What can we learnusing X-rays? (II)X-Rays: Probing Hot Universe!!

PhotonHow can we observe using X-rays?

X-Rays: Fly into space小質量主系列星からのX線

太陽観測衛星ＳＯＨＯがとらえた2003年10月28日の太陽フレア(X線写真)

太陽磁場と磁気リコネクション

太陽：激動するフレア

Big flare on V773Tau (TTS)~1033 erg s-1

フレア成分のパラメータ変化

原始星 (YSO前期)
激しい減光のため、軟Ｘ線でも観測は難しいが‥

YLW15 (ClassI) in Rho OphQuickTimeý Ç² TIFFÅià èkÇ»ÇµÅj êLí£ÉvÉçÉOÉâÉÄ Ç™Ç±ÇÃÉsÉNÉ`ÉÉÇ¾å©ÇÈÇžÇ½Ç…ÇÕïKóvÇ-Ç ÅBSpin period ~ 1 day!?

Intensity [counts s-1]
0.01 0.02

Sinusoidal light curve of WL60Spin period ~ 1 day!?

51015
Time [hour]

20チャンドラ衛星Unprecedented spatial resolution
Orion nebula
5 arcsec FWHM

Rosat HRI Observation

0.5 arcsec FWHM

Chandra ACIS Observation

-18
-20
-22

High extinction

optical UV
Low
extinction
FIR MIR

EUV

soft X

hard X

T Tauri

NIR

Protostar-24

log (Extinction crosssection)

How can we detect the central starof a protostar?

1010.1
0.01
Wavelength (μm)

0.001

Ryter etal. 1996

(Hard) X-rays could be powerful to detect them

観測ターゲット : ρ Oph分子雲
The nearest cloud
銀河系内の星形成領域(d~165 pc)
ρ Oph

銀河中心360o

Rho Oph
Imanishi, Koyama, Tsuboi 2000 ApJ
Imanishi et al. 2003 PASJ

red : 0.5-2.0keV
blue : 2.0-9.0keV

0.5pc

False Color in X-ray
観測される
スペクトル

元々のスペクトル

濃い塵星の環境Rho Oph
Imanishi, Koyama, Tsuboi 2000 ApJ
Imanishi et al. 2003 PASJ

red : 0.5-2.0keV
blue : 2.0-9.0keVClass I (classified in all references)
9/15
Class I candidates 15/19Detection rateof Class I 〜70%

Virtually all the Class I
could emit X rays.
0.5pc

>60% of the Class I showed flareswith 10,000-100,000 times
larger luminosities than solar flares.

6.4 keV line at flare from YLW16A (protostar)~1032 erg s-1~1031 erg s-1
6.4keV
EW〜100eV

2nd Flare: neutral Fe line
⇒reflection by a cool matterGeometry of the protostar

NH~5×1022cm-2
EW~15eVNH~ 5×1022cm-2
EW~100eV

6.4 keV line appearance (XRS)(Lx = 1032 erg s-1 )6.4 keV line appearance (Chandra)
6.4keV line appearedΔt ~160min⇒Δr~20AU
Reflecting material
exists within 20 AU
from the protostar.

Early Evolution of a Starage(yr)

105

104

106

107

108

Class III

Main
Sequence

Outflow
DiskEnvelope
Class IClass 0Protostar

Class II

T Tauri Star

QuickTime™ and a
Photo - JPEG decompressor
are needed to see this picture.

Lis et al. 98

Younger

ColderOrion Molecular CloudFalse color image ofOrion Molecular Cloud 3 region
Tsuboi et al. 2000 ApJ

Red : 0.5-3.0keVBlue : 3.0-8.0keV
Contour :dust emission map(Chini et al. 1997)X rays from Class 0 candidates were discovered.

X-ray Spectrum of the Class 0candidates
Row spectrum

Best fit model

QuickTime™ and a
GIF decompressor
are needed to see this picture.

NH > 10 23 H cm-2 !

A Cartoon of a protostrar itself and the vicinity

a few tens of Kelvin

10-100 million Kelvin

X-rayHigh-mass

X-ray World
Low-mass

Brown dwarf?

Flare from Old Brown Dwarf
LP944-20 (d ~ 5pc) t ~ 109 yrs

Rutledge et al. 2000, ApJ

Middle Aged
Brown Dwarf

I-band image

TWA 5Bt ~ 107 yrs
M* ~ 20MJ
D ~ 55 pc
2“(= 100 AU)~Boundary between
Planet and BD (13MJ) Neuhauser et al. 2000

TWA 5A/B

I bandX-Ray原始星 HH1/2 からのジェット

X-rays from HH 2 Pravdo et al. 2001 Nature

Spectrum of HH2
kT ~ 0.1 keV
Lx~5x10^29 erg s-1
V ~ 200 km s-1

High-mass

X-ray

X-ray

X-ray World

Low-mass

Brown dwarf

0.0001” で見える構造 (1)• Rho Oph, Taurus, R CrA (d~150 pc)
原子星の自転検出

磁場構造0.0001”~ 3Ro0.0001” で見える構造 (2)• Nearby RS CVns (d~10 pc)
RS CVn の磁場構造0.0001”~ 0.2Ro

0.0001” で見える構造 (3)• LP944-20 (d~5 pc)
BDの自転検出0.0001”~ 0.1Ro

Chandra Observation of HH 1/2

GTO Observation
8 Oct 2000, Exp. Time: 21.4 ksec,
ACIS-SX線の広がりX-rayHigh-mass

X-ray World
Low-mass

Brown dwarf?

Cometary X-rays• Lines from
Nitrogen andOxygen ion• Collisional
excitation bysolar wind

Comet 1999S4

Summary• Detection of X-rays from Class 0candidates.
• Access to the nature of Class I, BD, PN,comets,Jets….
Whole life of a star ?

Future Challenge• Extra solar planets ??
• Class 0 protostars

YLW16A (class I)

6.4keV

6.7keV
連続成分

中性鉄からの輝線
24回電離鉄からの輝線

X線で見た太陽X線天文学

てんま (1983)

USA 1960 ESA
Rocket

はくちょう (1979)

‘70
UHURU
SAS-3

あすか (1993)

HEAO-A
Einstein‘80
EXOSAT

ぎんが (1987)

‘90

ROSAT

RXTE
NewtonChandra2000
ISAS

Astro-E-II

Class I フレア成分
Class I 定常成分
Class II フレア成分
Class II 定常成分

Class I ではkT, NH大

NH vs kT

星の誕生
分子雲

原始星

104 yr0 yr

Tタウリ型星106 yr107 yrkT vs age of solar-mass YSOs
Class I FlareClass I QuiescentClass II FlareClass II Quiescent

SunImanishi, Koyama& Tsuboi 2001, ApJt [yr]

109

107

106 105 104

磁気リコネクションの起きかた

星の質量と構造の違い
小質量星

大質量星

放射

対流
放射

対流

Summary• 70% Class I protostars (and candidates)
are detected in Rho Oph with flare-liketime variabilities. Virtually, all Class Is
could emit X-rays possibly with magneticactivity.
• X-rays from two Class 0 candidates arediscovered. We need more sensitivity
and samples!

ACIS-S Spectrum of TWA 5B
kT = 0.3+/- 0.1 keV
Lx ~ 2 x 1027 ergs s-1