HST MEASURES OF MASS ACCRETION RATES IN THE … · C.F. Manara - HST Mass Accretion Rates Measures...
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Transcript of HST MEASURES OF MASS ACCRETION RATES IN THE … · C.F. Manara - HST Mass Accretion Rates Measures...
VLMS & BD – Garching, October 13th 2011
Carlo Felice Manara1,2,4, Massimo Robberto2, Nicola Da Rio2,3,Giuseppe Lodato4
HST MEASURES OF MASS ACCRETION RATES IN THE ORION NEBULA CLUSTER
1ESO Garching; 2STScI, Baltimore; 3ESA ESTEC; 4Università degli Studi di Milano, Italy
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
OUTLINES
1.HST Treasury program on the ONC 2.Methods to estimate Lacc
• 2CD (U-band excess) • Ha luminosity
3.Results • Macc vs age • Macc vs M*
• Dependence on both age and M*
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
• Cycle: 13 • GO10246 •Year: 2004-2005 •Orbits: 104 •P.I.: Robberto •Instruments: - ACS (B,V,Ha,I,Z) - WFPC2 (U,B,Ha,I) - NICMOS (J,H) •Parralel observations: - WFI(U,B,V,Ha,I,TiO) - ISPI (J,H,K)
HST Treasury Program on the ONC
Credits: NASA, ESA, M. Robberto
1 pc
10 arcmin
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
HST Treasury Program on the ONC
Science team: M. Robberto (STScI, PI), D. Soderblom (STScI), C. R. O’Dell (Vanderbilt), L. A. Hillenbrand (Caltech), M. Simon (Stony Brook), E. D. Feigelson (Penn State), J. Najita (NOAO), K. G. Stassun (Vanderbilt), J. Stauffer (JPL-Caltech), M. Meyer (ETH), J. Krist (JPL), N. Panagia (STScI), M. Romaniello (ESO), F. Palla (Arcetri), I.N. Reid (STScI), P. McCullough (STScI), R. Makidon (STScI), N. Da Rio (ESA), M. Andersen (ESA). STScI team: E. Bergeron (STScI), M. McMaster (STScI), V. Kozhurina-Platais (STScI), H. McLaughlin (STScI), K. Smith (MPIA), W. Sherry (NOAO) Graduate students: L. Ricci (ESO/Caltech), M. Reggiani (ETH), G. Scandariato (INAF Catania), W. Oosterheert (Groeningen), C. F. Manara (ESO) , Sara Sans (Innsbruck), T. Ananna (Bryn Mawr College), A. Miotello (Univ. Milano) Recent papers: Andersen et al. 2011, A&A, 534:10; Reggiani et al. 2011, A&A, 534:83
HST Treasury Program on the ONC - Atlas
Poster by A. Miotello #31
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Robberto et al., 2011, in prep.
WFPC2 dataset
1643 sources
F336W (U) F439W (B) F656N (Ha) F814W (I)
Detected 1021 997 1342 1610
Upper limit 481 521 215 11
For 1131 of the WFPC2 sources Teff from
Hillenbrand 1997 (specctra), Da Rio et al. 2010, 2011 (narrowband photometry) available.
439 sources with U, B, I band photometry and Teff available. 339 of them are used (corrected for red
leak - no proplyds, binaries, big errors…)
1027 sources with Ha band photometry , Teff and AV available. 682 of them are used (no proplyds,
binaries, edge-on disks…)
2CD
LHa
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
UBI Diagram (2CD) with:
Two Colors Diagram
•Atmosphere Models (Allard et al.2010)
•Accretion spectrum (Calvet et al. 1998)
•75% optically thick emission (blackbody at 8000K) •25% optically thin emission (HII region with n=104 cm-3)
• Extinction law (Cardelli et al. 1989)
+ HII region (magnetospheric emission) (more important for low accretion rates)
Empirically calibrated
RV = 3.1
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Two Colors Diagram – Accretion Spectrum
Observed 2CD
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Two Colors Diagram – Accretion Spectrum
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Observed 2CD
6000 K
5500 K
5000 K
4500 K
4000 K
3500 K
3200 K
Two Colors Diagram – Accretion Spectrum
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Dereddened 2CD
6000 K
5500 K
5000 K
4500 K
4000 K
3500 K
3200 K
Two Colors Diagram – Accretion Spectrum
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Basic accretion spectrum
6000 K
5500 K
5000 K
4500 K
4000 K
3500 K
3200 K
Two Colors Diagram – Accretion Spectrum
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Basic + Magnetosphere
6000 K
5500 K
5000 K
4500 K
4000 K
3500 K
3200 K
Derivation of LACC and AV
The intersection of the reddening line (red) and the accretion curve (blue) determines simultaneously Lacc and AV.
Estimate of Lacc and AV obtained for 245 sources.
Method – (1) 2CD C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
LACC from LHa - calibration
Linear regression :
148 sources
Method – (2) Ha
528 sources with Lacc estimated from LHa
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
HR Diagram – Masses – Macc
Derivation of Ṁacc for 730 sources (244 with 2CD and 486 from LHa)
Method – HRD
2CD
Ha
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Macc decreases with time
Ṁacc ~ t-(1.2±0.3)
Results
Hartmann et al., 1998: Ṁacc ~ t-1.5
2CD
Ha
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Muzerolle et al., 2003: Ṁacc ~ M*2
Natta et al., 2006: Ṁacc ~ M*1.8±0.2
Rigliaco et al., 2011: Ṁacc~ M*1.6±0.4
Ṁacc ~ M*1.5±0.6
Macc increases with Mstar
Results
2CD
Ha
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Macc depends on age & Mstar
Results
log M log Age
log
Mac
c
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Results
Macc depends on age & Mstar – new results
log
Mac
c
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Results
Macc depends on age & Mstar – new results lo
g M
acc
Mstar ~ 0.13 Msun Ṁacc ~ t-1.5
Mstar ~ 0.3 Msun Ṁacc ~ t-1.07
Mstar ~ 0.5 Msun Ṁacc ~ t-0.8
Slower decay for higher mass stars
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
Results
Macc depends on age & Mstar – new results lo
g M
acc
age ~ 1 Myr Ṁacc ~ M*1.24
age ~ 2 Myr Ṁacc ~ M*1.59
age ~ 5 Myr Ṁacc ~ M*2
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Manara et al., 2011, in prep.
C.F. Manara - HST Mass Accretion Rates Measures in the ONC – VLMS & BD, ESO, Garching, Oct 13 2011
Macc estimate for 730 sources with two methods (2CD and Ha)
Fit of the the warped plane Macc – age – Mstar
Different behaviour for different mass and age ranges.
More massive stars evolve more slowly than less massive stars.
CONCLUSIONS