J/ApJ/755/154 Mass accretion rates from HST in the ONC (Manara+, 2012)
Hubble Space Telescope measures of mass accretion rates in the Orion Nebula
Cluster.
Manara C.F., Robberto M., Da Rio N., Lodato G., Hillenbrand L.A.,
Stassun K.G., Soderblom D.R.
<Astrophys. J., 755, 154 (2012)>
=2012ApJ...755..154M 2012ApJ...755..154M
ADC_Keywords: Accretion ; Clusters, open ; Photometry, HST ; Equivalent widths ;
Stars, masses ; Stars, ages
Keywords: accretion, accretion disks; protoplanetary disks; stars: formation;
stars: pre-main sequence
Abstract:
The present observational understanding of the evolution of the mass
accretion rates (dM/dtacc) in pre-main-sequence stars is limited by
the lack of accurate measurements of dM/dtacc over homogeneous and
large statistical samples of young stars. Such observational effort is
needed to properly constrain the theory of star formation and disk
evolution. Based on Hubble Space Telescope/WFPC2 observations, we
present a study of dM/dtacc for a sample of ∼700 sources in the
Orion Nebula Cluster, ranging from the hydrogen-burning limit to
M*∼2M☉. We derive dM/dtacc from both the U-band excess and the
Hα luminosity (LHα), after determining empirically both
the shape of the typical accretion spectrum across the Balmer jump and
the relation between the accretion luminosity (Lacc) and
LHα, which is
Lacc/L☉=(1.31±0.03).LHα/L☉_+(2.63±0.13). Given
our large statistical sample, we are able to accurately investigate
relations between dM/dtacc and the parameters of the central star
such as mass and age.
Description:
In this work, we consider the HST observations obtained for the HST
Treasury Program on the ONC (GO program 10246; see Robberto et al. 2013,
Cat. J/ApJS/207/10). In particular, we use the WFPC2 observations
carried out between 2004 October and 2005 April in the filters F336W
(∼stroemgren u) F439W (∼Johnson B), F656N (narrowband filter centered
on Hα), and F814W (∼ Cousins I).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 63 244 Stellar parameters of the sources where the 2CD
method leads to a determination of AV and Lacc
table3.dat 66 486 Stellar parameters of the sources where we assumed
AV from Da Rio et al. (2012, Cat. J/ApJ/748/14)
and we estimate Lacc from the Hα luminosity
table4.dat 74 244 Accretion values of the sources where the 2CD
method leads to a determination of AV and Lacc,
according to different evolutionary models
table5.dat 74 486 Accretion values of the sources where we assumed AV
from Da Rio et al. (2012, Cat. J/ApJ/748/14) and
we estimate Lacc from the Hα luminosity,
according to different evolutionary models
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJS/208/28 : Hα survey in the ONC (Szegedi-Elek+, 2013)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/A+A/534/A10 : HST/NICMOS III imaging in ONC (Andersen+, 2011)
J/AJ/136/2136 : HST/ACS Atlas of Great Orion Nebula proplyds (Ricci+, 2008)
J/MNRAS/374/1413 : SCUBA survey of Orion (Nutter+, 2007)
J/ApJ/642/1140 : Disk mass loss in the Orion Nebula Cluster (Olczak+, 2006)
J/AJ/129/363 : Spectroscopy in Orion Nebula Cluster (Sicilia-Aguilar+, 2005)
J/AJ/111/846 : Orion HST survey (O'Dell+ 1996)
http://archive.stsci.edu/prepds/orion/ : HST Treasury Program on the ONC
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- OM Orion Master Catalog entry number (G1)
6 I1 h RAh Hour of Right Ascension (J2000)
8- 9 I2 min RAm Minute of Right Ascension (J2000)
11- 17 F7.4 s RAs Second of Right Ascension (J2000)
19 A1 --- DE- Sign of the Declination (J2000)
20 I1 deg DEd Degree of Declination (J2000)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000)
25- 31 F7.4 arcsec DEs Arcsecond of Declination (J2000)
33- 36 I4 K Teff [2906/5943] Effective temperature (G2)
38- 42 F5.2 mag Av [-0.2/4.5] Extinction in the V band
44- 48 F5.2 [Lsun] logL [-2.1/1] Log of the luminosity
50- 53 F4.2 Rsun Rad [0.3/4.2] Star radius
55- 61 F7.4 mag Iacc [-2.2/0] I band excess due to accretion
63 I1 --- CL [1/3] Confidence level (in σ)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- OM Orion Master Catalog entry number (G1)
6 I1 h RAh Hour of Right Ascension (J2000)
8- 9 I2 min RAm Minute of Right Ascension (J2000)
11- 17 F7.4 s RAs Second of Right Ascension (J2000)
19 A1 --- DE- Sign of the Declination (J2000)
20 I1 deg DEd Degree of Declination (J2000)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000)
25- 31 F7.4 arcsec DEs Arcsecond of Declination (J2000)
33- 36 I4 K Teff [2778/9309] Effective temperature (G2)
38- 42 F5.2 mag Av [-2/11] Extinction in the V band (G2)
44- 48 F5.2 [Lsun] logL [-2.3/1.7] Log of the luminosity
50- 53 F4.2 Rsun Rad [0.3/4.4] Star radius
55- 60 F6.2 0.1nm EW [3/983] Equivalent width of Hα (Å)
62- 66 F5.2 [Lsun] logLHa [-6.2/-1.3] Log of the Hα luminosity
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Byte-by-byte Description of file: table[45].dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- OM Orion Master Catalog entry number (G1)
6- 10 F5.2 [Lsun] logLacc [-5.5/0.9]? Log of the accretion luminosity
12 A1 --- f_logLacc [I] I=-∞ (Lacc=0)
14- 17 F4.2 Msun M1 [0.04/2.5] Mass (2)
19- 21 F3.1 [yr] logA1 [4.4/8] Log of the age (2)
23- 28 F6.2 [Msun/yr] logMd1 [-12.2/-6]? Log of mass accretion rate (2)
30 A1 --- f_logMd1 [NI] N=NaN, I=-∞ (Md1=0)
32- 35 F4.2 Msun M2 ? Mass (3)
37 A1 --- f_M2 [N] N=NaN
39- 41 F3.1 [yr] logA2 ? Log of the age (3)
43 A1 --- f_logA2 [N] N=NaN
45- 50 F6.2 [Msun/yr] logMd2 ? Log of mass accretion rate (3)
52 A1 --- f_logMd2 [NI] N=NaN, I=-∞ (Md2=0)
54- 57 F4.2 Msun M3 ? Mass (4)
59 A1 --- f_M3 [N] N=NaN
61- 63 F3.1 [yr] logA3 ? Log of the age (4)
65 A1 --- f_logA3 [N] N=NaN
67- 72 F6.2 [Msun/yr] logMd3 ? Log of mass accretion rate (4)
74 A1 --- f_logMd3 [NI] N=NaN, I=-∞ (Md3=0)
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Note (2): Obtained with D'Antona & Mazzitelli (1994ApJS...90..467D 1994ApJS...90..467D) models.
Note (3): Obtained with Siess et al. (2000A&A...358..593S 2000A&A...358..593S) models
Note (4): Obtained with Palla & Stahler (1999ApJ...525..772P 1999ApJ...525..772P) models.
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Global notes:
Note (G1): Orion Master catalog entry number, <[MRD2012] NNNN> in Simbad.
(See also Robberto et al. 2013, Cat. J/ApJS/207/10;
<[RSB2013] WFPC2 NNNN> in Simbad).
Note (G2): From Da Rio et al. (2012, Cat. J/ApJ/748/14) and references therein.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Mar-2014