Access to Astronomical Catalogues

← Click to display the menu
J/ApJ/706/1484        Photometry and spectroscopy in IC 2391 (Boudreault+, 2009)

A constraint on brown dwarf formation via ejection: radial variation of the stellar and substellar mass function of the young open cluster IC 2391. Boudreault S., Bailer-Jones C.A.L. <Astrophys. J., 706, 1484-1503 (2009)> =2009ApJ...706.1484B
ADC_Keywords: Clusters, open ; Photometry ; Spectroscopy ; Radial velocities ; Stars, M-type ; Stars, masses ; Effective temperatures ; Spectral types ; Equivalent widths Keywords: open clusters and associations: individual (IC 2391) - stars: low-mass, brown dwarfs - stars: luminosity function, mass function Abstract: We present the stellar and substellar mass function (MF) of the open cluster IC 2391, plus its radial dependence, and use this to put constraints on the formation mechanism of brown dwarfs (BDs). Our multi-band optical and infrared photometric survey with spectroscopic follow-up covers 11deg2, making it the largest survey of this cluster to date. From our preliminary spectroscopic follow-up, to confirm BD status and cluster membership, we find that all candidates are M dwarfs (in either the field or the cluster), demonstrating the efficiency of our photometric selection method in avoiding contaminants (e.g., red giants). About half of our photometric candidates for which we have spectra are spectroscopically confirmed as cluster members; two are new spectroscopically confirmed BD members of IC 2391. Description: The survey consists of 35 34'x33' fields extending to 3° from the center of the cluster and centered on RA=08:40:36 and DE=-53:02:00 (Figure 1). The optical observations were carried out in four runs with the Wide Field Image (WFI) on the 2.2m telescope at La Silla in: 1999 January 24-February 9, 2000 January 20-24, 2007 March 10-23, and 2007 May 15-18. The deep fields in our survey were observed in four medium bands filters, namely, 770/19, 815/20, 856/14, and 914/27 (where the filter name notation is central wavelength on the full width at half-maximum, FWHM, in nm) and one broadband filter, Rc. We also observed all radial fields, including the outward fields, in the J band using the CPAPIR on the 1.5m telescope at Cerro Tololo, Chile (runs on 2007 February 28-March 3 and 2007 March 10). The J filter of CPAPIR is centered at 1250nm with a FWHM of 160nm. The spectroscopic observations were carried out with HYDRA, a multi-object, fiber-fed spectrograph on the 4m telescope at Cerro Tololo on the nights of 2007 January 6 and 7. Only two fields could be observed: the deep fields 15 and 20 with a coverage of 6429-8760Å centered at 7593Å and a spectral resolution of 4.0Å. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 91 3111 All photometric candidates of our survey table3.dat 96 10 Photometric candidates already detected by previous studies (table corrected by the author) table4.dat 77 17 Stellar parameters from the objects observed in our spectroscopic follow-up table6.dat 55 17 Spectroscopic data, photometric and spectroscopic membership status
See also: J/A+A/501/553 : Equivalent widths of IC 2602 + IC 2391 stars (D'Orazi+, 2009) J/A+A/461/509 : Membership and spectroscopy of IC 2391 (Platais+, 2007) J/A+A/468/151 : Nearby open clusters radii and masses (Piskunov+, 2007) J/A+A/430/287 : XMM observations of IC 2391 stars (Marino+, 2005) J/MNRAS/355/959 : Proper motions of IC 2391 possible members (Dodd+, 2004) J/A+A/372/862 : Lithium abundances in IC 2602 and IC 2391 (Randich+, 2001) J/ApJS/134/103 : Low-mass members of IC 2391 (Barrado y Navascues+, 2001) J/A+A/345/471 : Memberships of open clusters (Robichon+, 1999) J/A+AS/126/357 : Members of IC 2391 (Rolleston+ 1997) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Field Field number 4- 6 I3 --- ID Running identification number 8 I1 h RAh Hour of Right Ascension (J2000) 10- 11 I2 min RAm Minute of Right Ascension (J2000) 13- 18 F6.3 s RAs Second of Right Ascension (J2000) 20 A1 --- DE- Sign of the Declination (J2000) 21- 22 I2 deg DEd Degree of Declination (J2000) 24- 25 I2 arcmin DEm Arcminute of Declination (J2000) 27- 31 F5.2 arcsec DEs Arcsecond of Declination (J2000) 33- 38 F6.3 mag Rmag ? Observed WFI Rc band magnitude 40- 45 F6.3 mag O770/19 ? Observed 770/19 medium band magnitude (G1) 47- 52 F6.3 mag O815/20 Observed 815/20 medium band magnitude (G1) 54- 59 F6.3 mag O856/14 ? Observed 856/14 medium band magnitude (G1) 61- 66 F6.3 mag O914/27 Observed 914/27 medium band magnitude (G1) 68- 73 F6.3 mag Jmag ? Observed CPARIR Johnson J-band magnitude 75- 79 F5.3 Msun Mass Mass (1) 81- 84 I4 K Teff Effective temperature (1) 86- 91 F6.3 mag P815/20 Predicted 815/20 medium band magnitude (2)
Note (1): The error on the determination of masses and effective temperature are: * ΔTeff=140K and ΔM=0.1M for stars (M>0.2 M), * ΔTeff=230K and ΔM=0.05M for very low mass star (VLMS) (0.072<M<0.2), * ΔTeff=420K and ΔM=0.02M for brown dwarfs (M<0.072M). Note (2): Based on photometric determination of Teff and mass.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Field [18,37] Field 4- 6 I3 --- ID Running identification number 8 I1 h RAh Hour of right ascension (J2000) 10- 11 I2 min RAm Minute of right ascension (J2000) 13- 18 F6.3 s RAs Second of right ascension (J2000) 20 A1 --- DE- Sign of declination (J2000) 21- 22 I2 deg DEd Degree of declination (J2000) 24- 25 I2 arcmin DEm Arcminute of declination (J2000) 27- 31 F5.2 arcsec DEs Arcsecond of declination (J2000) 33- 38 F6.3 mag O815/20 Observed 815/20 medium band magnitude (G1) 40- 44 F5.3 Msun Mass Mass 46- 49 I4 K Teff Effective temperature 51- 56 F6.3 mag P815/20 Predicted 815/20 medium band magnitude 58- 78 A21 --- OName Counterpart name (1) 80- 85 F6.3 mag Ic ? Cousins I-band magnitude (1) 87- 91 F5.3 mag (R-I)c ? (R-I)c color index (1) 93- 96 I4 K Teff2 ? Effective temperature (1)
Note (1): Object 8 is from Patten & Pavlovsky (1999PASP..111..210P; <Cl* IC 2391 PP 8> in Simbad), CTIO objects are from Barrado y Navascues et al. (2004ApJ...614..386B; <Cl* IC 2391 CTIO NN> in Simbad), object 155 is from Dodd (2004, Cat. J/MNRAS/355/959; <Cl* IC 2391 D 155> in Simbad) while the 2XMM objects are from XMM-Newton. The values of Ic, (R-I)c, and Teff given in the last three columns are taken from each of the previous studies.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Field [15/20] Field number 4- 6 I3 --- ID Running identification number 8 I1 h RAh Hour of right ascension (J2000) 10- 11 I2 min RAm Minute of right ascension (J2000) 13- 18 F6.3 s RAs Second of right ascension (J2000) 20 A1 --- DE- Sign of declination (J2000) 21- 22 I2 deg DEd Degree of declination (J2000) 24- 25 I2 arcmin DEm Arcminute of declination (J2000) 27- 31 F5.2 arcsec DEs Arcsecond of declination (J2000) 33- 36 F4.1 --- S/N Signal to noise ratio 38- 41 A4 --- SpT MK spectral type 43- 46 I4 K Teff Effective temperature (1) 48- 52 F5.3 Msun Mass Mass (1) 54- 59 F6.3 mag O815/20 Observed 815/20 medium band magnitude (G1) 61- 64 I4 K Tph Photometric effective temperature 66- 70 F5.3 Msun Mph Photometric mass 72- 77 F6.3 mag P815/20 Predicted 815/20 medium band magnitude
Note (1): The errors on the determination of masses and effective temperature based on spectroscopy are: * ΔTeff=190K and ΔM=0.03M for spectra with S/N>10 (for an error of 1 subclass) * ΔTeff=320K and ΔM=0.04M_☉ for spectra with 5<S/N<10. (for an error of 1.5 subclass)
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Field [15/20] Field number 4- 6 I3 --- ID Running identification number 8- 11 F4.1 --- S/N Signal to noise ratio 13- 16 A4 --- SpT MK spectral type 18- 23 F6.2 0.1nm W(Ha) ? Hα equivalent width 25- 28 F4.2 0.1nm W(8182) ? NaIλ8182Å equivalent width 30- 33 F4.2 0.1nm W(8194) ? NaIλ8194Å equivalent width 35- 40 F6.2 km/s RV ? Radial velocity 42- 46 F5.2 km/s e_RV ? Radial velocity uncertainty 48 A1 --- l_W(Li) Limit flag on W(Li) (1) 49- 51 F3.1 0.1nm W(Li) ? LiI equivalent width 53- 55 A3 --- Mm [Yes/No ] Spectroscopic member? (2)
Note (1): A value of <0.1 as equivalent width of lithium indicates the presence of a feature at 6708Å, but no reliable measurement of equivalent width can be done. Note (2): All objects from Table 4 are presented here, but with physical parameters and with membership status based on photometry and spectroscopy (i.e., which satisfy our spectroscopic criterion). We do not reject objects which does not present a feature of LiI due to low S/N if the other criteria are satisfied (e.g., IC2391-WFI-15-005).
Global Notes: Note (G1): Where the filter name notation is central wavelength on the full width at half maximum, FWHM, in nm.
Nomenclature Notes: Stars are <[BB2009] IC2391-WFI-FF-NNN> in Simbad. History: Tables 2, 4 and 6: From electronic version of the journal Table 3: corrected version by Steve Boudreault.
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 28-Dec-2011
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact