J/ApJ/832/87 Members of the young open cluster IC 2395 (Balog+, 2016)
Protoplanetary and transitional disks in the open stellar cluster IC 2395.
Balog Z., Siegler N., Rieke G.H., Kiss L.L., Muzerolle J., Gutermuth R.A.,
Bell C.P.M., Vinko J., Su K.Y.L., Young E.T., Gaspar A.
<Astrophys. J., 832, 87-87 (2016)>
=2016ApJ...832...87B 2016ApJ...832...87B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; YSOs ; Photometry, UBVRI ; Photometry, infrared ;
Spectroscopy ; Spectral types ; Cross identifications
Keywords: circumstellar matter; infrared: stars;
open clusters and associations: individual: IC 2395;
stars: pre-main sequence
Abstract:
We present new deep UBVRI images and high-resolution multi-object
optical spectroscopy of the young (∼6-10Myr old), relatively nearby
(800pc) open cluster IC 2395. We identify nearly 300 cluster members
and use the photometry to estimate their spectral types, which extend
from early B to middle M. We also present an infrared imaging survey
of the central region using the IRAC and MIPS instruments on board the
Spitzer Space Telescope, covering the wavelength range from 3.6 to
24µm. Our infrared observations allow us to detect dust in
circumstellar disks originating over a typical range of radii from
∼0.1 to ∼10 au from the central star. We identify 18 Class II, 8
transitional disk, and 23 debris disk candidates, respectively, 6.5%,
2.9%, and 8.3% of the cluster members with appropriate data. We apply
the same criteria for transitional disk identification to 19 other
stellar clusters and associations spanning ages from ∼1 to ∼18Myr. We
find that the number of disks in the transitional phase as a fraction
of the total with strong 24µm excesses ([8]-[24]≥1.5) increases
from (8.4±1.3)% at ∼3Myr to (46±5)% at ∼10Myr. Alternative
definitions of transitional disks will yield different percentages but
should show the same trend.
Description:
IC 2395 was observed using IRAC on Spitzer in 2003 December as part of
a GTO program (PID 58, PI Rieke, Evolution and Lifetimes of
Protoplanetary Disks). The survey covers an area of ∼44'x44' in each
of the four IRAC channels. IC 2395 was also observed using MIPS on
Spitzer in 2003 as part of the same GTO program.
Our optical observations were made with the 1.5m telescope at Cerro
Tololo Inter-American Observatory (CTIO) on 2003 January 23 and 24 as
part of a three-day campaign (2003 January 22, 23, and 24) to provide
optical data in support of Spitzer observations for IC 2395 and NGC
2451 (discussed in a separate paper; Balog+ 2009, J/ApJ/698/1989). The
observations were made through Johnson-Cousins UBVRI filters.
We acquired AAOmega spectra using the Anglo-Australian Telescope at
Siding Spring, Australia on three nights (2009 December 17-23) in
conditions of clear skies with 1.5-2.5 arcsec seeing.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 91 57 General characteristics of IC 2395 cluster members
from Claria+ 2003, J/A+A/409/541
table3.dat 92 295 Optical photometry of cluster members
table4.dat 107 295 Infrared photometry of cluster members
table5.dat 51 49 Disk candidates in IC 2395
--------------------------------------------------------------------------------
See also:
B/ocl : Optically visible open clusters and Candidates (Dias+ 2002-2015)
B/mk : Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)
III/257 : RAVE second data release (Zwitter+, 2008)
I/297 : NOMAD Catalog (Zacharias+ 2005)
V/126 : MEGA-H proper motion catalog (Kharchenko, 2004)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/MNRAS/442/2543 : Dust disks around star in young clusters (Yasui+, 2014)
J/A+A/564/A79 : Proper motions of open clusters from UCAC4 (Dias+, 2014)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/ApJ/768/25 : Spitzer & Herschel obs. of debris disks (Gaspar+, 2013)
J/ApJ/750/98 : 24um obs. of AFGKM stars of 3 clusters (Urban+, 2012)
J/A+A/548/A97 : Catalogue of variable stars in open clusters (Zejda+, 2012)
J/PAZh/38/763 : XHIP-II: Clusters and associations (Francis+, 2012)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/698/1989 : Spitzer survey of NGC 2451 (Balog+, 2009)
J/ApJ/660/1532 : Spitzer/IRAC-MIPS survey of NGC 2244 (Balog+, 2007)
J/A+A/446/949 : Open clusters proper motions based on UCAC2 (Dias+, 2006)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/ApJS/161/118 : byHα photometry in open clusters (McSwain+, 2005)
J/A+A/409/541 : UBV photometry of IC 2395 (Claria+, 2003)
J/A+A/376/441 : Absolute proper motions of 112 open clusters (Dias+, 2001)
J/A+AS/146/251 : Open clusters absolute proper motions. I. (Baumgardt+, 2000)
J/PAZh/25/10 : Young open clusters space-age distribution (Dambis, 1999)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [CLP2003] [1/268] Identifier (1)
5- 7 I3 --- ID [1/288]? ID from table 4 (2)
9 I1 h RAh [8] 2MASS hour of right ascension (J2000)
11- 12 I2 min RAm [40/44] Minute of right ascension (J2000)
14- 17 F4.1 s RAs Second of right ascension (J2000)
19 A1 --- DE- [-] 2MASS sign of declination (J2000)
20- 21 I2 deg DEd [47/48] 2MASS degree of declination (J2000)
23- 24 I2 arcmin DEm Arcminute of declination (J2000)
26- 29 F4.1 arcsec DEs Arcsecond of declination (J2000)
31- 36 A6 --- SpT MK spectral type
38 I1 --- r_SpT [1/4]? SpT reference (3)
40- 44 F5.2 mag Vmag [5.4/14.6] V-band magnitude (1)
46- 50 F5.2 mag B-V [-0.2/0.7] B-V color index (1)
52- 56 F5.1 mas/yr pmRA [-13.7/6.6]? Proper motion in RA
(µαcosδ) (4)
58- 60 F3.1 mas/yr e_pmRA [0.6/5.9]? pmRA uncertainty
62- 65 F4.1 mas/yr pmDE [-1.9/13.3]? Proper motion in DEC
(µδ) (4)
67- 69 F3.1 mas/yr e_pmDE [0.4/5.8]? pmDE uncertainty
71- 89 A19 --- OName Other designations (5)
91 A1 --- f_OName Flag on OName (6)
--------------------------------------------------------------------------------
Note (1): From Claria+, 2003, J/A+A/409/541; uncertainties are described
therein.
Note (2): If no cross-reference to Table 4 is provided, we do not confirm the
membership assignment.
Note (3): References for spectral type as follows:
1 = Pickles & Depagne (2010, VI/135),
2 = Skiff (2014, B/mk),
3 = from photometry (see text),
4 = from Hβ photometry (Paunzen 2015, J/A+A/580/23) calibrated through
(Crawford & Mander 1966AJ.....71..114C 1966AJ.....71..114C).
Note (4): Proper motions from NOMAD; Zacharias+ (2004, I/297).
Mean cluster proper motion derived in Section 3.1.1 is
µαcosδ=-3.9±0.4mas/yr and
µδ=3.0±0.4mas/yr.
Note (5):
CD or CPD = photographic plates from the Annals of the Cape Observatory,
L = Lynga (1959ArA.....2..379L 1959ArA.....2..379L, in Simbad),
HD = Henry Draper (see III/135 and III/182).
Note (6): Flag as follows:
d = Probable binary.
e = Likely ellipsoidal variable (Morris 1985ApJ...295..143M 1985ApJ...295..143M), hence binary.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Running index number
5- 13 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) (1)
15- 23 F9.5 deg DEdeg Declination in decimal degrees (J2000) (1)
25- 26 A2 --- SpT MK spectral type (2)
28- 33 F6.3 mag Umag [5.9/21.9]? The CTIO Johnson U band magnitude
35- 39 F5.3 mag e_Umag [0.002/0.3]? Uncertainty in Umag
41- 46 F6.3 mag Bmag [7.6/21.4]? The CTIO Johnson B band magnitude
48- 52 F5.3 mag e_Bmag [0.002/0.2]? Uncertainty in Bmag
54- 59 F6.3 mag Vmag [7.6/20.8]? The CTIO Johnson V band magnitude
61- 66 F6.3 mag e_Vmag [0.003/20.8]? Uncertainty in Vmag
68- 73 F6.3 mag Rmag [7.8/19.3]? The CTIO Cousins R band magnitude
75- 79 F5.3 mag e_Rmag [0.003/0.2]? Uncertainty in Rmag
81- 86 F6.3 mag Imag [6.7/17.5]? The CTIO Cousins I band magnitude
88- 92 F5.3 mag e_Imag [0.003/0.2]? Uncertainty in Imag
--------------------------------------------------------------------------------
Note (1): 2MASS celestial coordinates are used except for ID 110 where IRAC
coordinates are used.
Note (2): All spectral types in this table are estimated from photometry
(see text for details).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Running index number
5- 10 F6.3 mag Jmag [5.8/16]? 2MASS J band magnitude
12- 16 F5.3 mag e_Jmag [0.01/0.2]? Uncertainty in Jmag
18- 23 F6.3 mag Hmag [5.8/15.3]? 2MASS H band magnitude
25- 29 F5.3 mag e_Hmag [0.02/0.2]? Uncertainty in Hmag
31- 36 F6.3 mag Ksmag [5.9/14.8] 2MASS KS band magnitude
38- 42 F5.3 mag e_Ksmag [0.01/0.2] Uncertainty in Ksmag
44- 49 F6.3 mag 3.6mag [6.1/14.6]? Spitzer/IRAC 3.6um band magnitude
51- 55 F5.3 mag e_3.6mag [0.002/0.09]? Uncertainty in 3.6mag
57- 62 F6.3 mag 4.5mag [6.1/14.5]? Spitzer/IRAC 4.5um band magnitude
64- 68 F5.3 mag e_4.5mag [0.002/0.06]? Uncertainty in 4.5mag
70- 75 F6.3 mag 5.8mag [6.1/14.6]? Spitzer/IRAC 5.8um band magnitude
77- 81 F5.3 mag e_5.8mag [0.002/0.2]? Uncertainty in 5.8mag
83- 88 F6.3 mag 8.0mag [6/14.7]? Spitzer/IRAC 8um band magnitude
90- 94 F5.3 mag e_8.0mag [0.001/1]? Uncertainty in 8.0mag
96-101 F6.3 mag 24mag [6/11.2]? Spitzer/MIPS 24 micron band magnitude
103-107 F5.3 mag e_24mag [0.007/0.08]? Uncertainty in 24mag
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID [14/283] Identifier as in tables 3 and 4
5-10 A6 --- SpT ? MK spectral type
12-17 F6.3 mag [3.6]-[5.8] Spitzer/IRAC ([3.6]-[5.8]) color index
19-23 F5.3 mag e_[3.6]-[5.8] Uncertainty on [3.6]-[5.8]
25-30 F6.3 mag [4.5]-[8] Spitzer/IRAC ([4.5]-[8]) color index
32-36 F5.3 mag e_[4.5]-[8] Uncertainty on [4.5]-[8]
38-42 F5.3 mag [8]-[24] Spitzer ([8]-[24]) color index
44-48 F5.3 mag e_[8]-[24] Uncertainty on [8]-[24]
50-51 A2 --- Type ? Disk type (1)
--------------------------------------------------------------------------------
Note (1): Disk type as follows:
D = debris disk: star in IC 2395 with [8]-[24]>0.15 and spectral type of F
or earlier or with [8]-[24]<1.5 and of later spectral type (18 instances)
D? = debris disk candidate: no spectral type could be assigned photometrically
(and none was available spectroscopically) (5 instances)
II = class II source: [3.6]-[5.8]>0.4 and [4.5]-[8]>0.268x([3.6]-[5.8])+0.393
and detection at 22 or 24um (18 instances)
T = transitional disk: i.e., [3.6]-[5.8]<0.4 and [8]-[24]>1.5 (5 instances)
WT = weak transitional, [8]-[24]<2.5 (3 instances)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Feb-2017