J/AJ/119/3026 Circumstellar disk candidates in Orion (Rebull+, 2000)
Circumstellar disk candidates identified from ultraviolet excesses in the
Orion nebula cluster flanking fields.
Rebull L.M., Hillenbrand L.A., Strom S.E., Duncan D.K., Patten B.M.,
Pavlovsky C.M., Makidon R., Adams M.T.
<Astron. J. 119, 3026 (2000)>
=2000AJ....119.3026R 2000AJ....119.3026R
ADC_Keywords: Stars, pre-main sequence ; Photometry, Cousins ; Photometry, UBV ;
Keywords: stars: pre-main-sequence
Abstract:
We present an optical study of four 45'x45' fields centered ∼0.5°
east, west, north, and south of the Orion Nebula Cluster center. We
have measured V and IC photometry for ∼5000 stars, and U photometry
for ∼1600 of these. We have obtained spectral classifications for ∼300
of the stars with UVIC photometry plus an additional ∼200 stars
located outside the area of our photometric survey. Dereddened
photometry allows us to investigate the evidence for circumstellar
accretion disks from excess emission at ultraviolet wavelengths, as
well as the mass and age distributions of our sample. We find ∼230
active accretion disk candidates and estimate the accretion disk
fraction at ≳40%. We use the magnitude of the ultraviolet excess to
infer disk accretion rates. The mass accretion rate (dM/dt) decreases
slowly with age over the limited age range spanned by our data,
1-3Myr, and increases slowly with mass over the limited mass range
0.2-1.2 M☉.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 81 1700 Observations I: stars in the Orion locus
table2.dat 81 38 Observations II: Apparent field stars with spectra
table3.dat 38 171 Observations III: stars with spectroscopy only
--------------------------------------------------------------------------------
See also:
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
J/AJ/116/1816 : JHKLMNOPQ photometry in Orion cluster (Hillenbrand+, 1998)
Byte-by-byte Description of file: table[12].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- T [1,2] Table number
2 A1 --- --- [-] Separator
3- 6 I4 --- [RHS2000] Sequential number (1)
8 I1 --- Field Field number
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 19 F4.1 s RAs [0,60] Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 31 F4.1 arcsec DEs [0,60] Declination (J2000.0)
33- 37 F5.2 mag Icmag Cousins I magnitude
39- 42 F4.2 mag e_Icmag rms uncertainty on Icmag
44- 47 F4.2 mag V-Ic V-IC colour index
49- 52 F4.2 mag e_V-Ic rms uncertainty on V-Ic
54- 58 F5.2 mag U-V ? U-V colour index
60- 63 F4.2 mag e_U-V ? rms uncertainty on U-V
65- 69 A5 --- SpType Spectral type
71- 75 F5.2 mag AImag ? Extinction in IC band
77- 81 F5.2 mag AVmag ? Extinction in V band
--------------------------------------------------------------------------------
Note (1): In Simbad, Table 1: <[RHS2000] 1-NNNN>, Table 2: <[RHS2000] 2-NN>
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- T [3] Table number
2 A1 --- --- [-] Separator
3- 6 I4 --- [RHS2000] Sequential number ([RHS2000] 3-NNNN in Simbad)
8 I1 --- Field Field number
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 19 F4.1 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 32 F5.2 arcsec DEs Declination (J2000.0)
34- 38 A5 --- SpType Spectral type
--------------------------------------------------------------------------------
History:
From AJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 31-Aug-2000