J/AJ/143/3 Hα emission stars in IC 1274 (Dahm+, 2012)
The young cluster in IC 1274.
Dahm S.E., Herbig G.H., Bowler B.P.
<Astron. J., 143, 3 (2012)>
=2012AJ....143....3D 2012AJ....143....3D
ADC_Keywords: Photometry, UBVRI ; Stars, emission ; Equivalent widths ;
Photometry, H-alpha ; Associations, stellar
Keywords: ISM: individual objects (IC 1274, Lynds 227) -
stars: pre-main sequence - stars: variables: T Tauri, Herbig Ae/Be
Abstract:
IC 1274 is a faintly luminous nebula lying on the near surface of the
Lynds 227 (L227) molecular cloud. Its cavity-like morphology is
reminiscent of a blistered star-forming region. Four luminous,
early-type (B0-B5) stars are located within a spherical volume ∼5' in
diameter that appears to be clear of heavy obscuration. Approximately
centered in the cleared region is the B0 V star HD 166033, which is
thought to be largely responsible for the cavity's excavation. Over 80
Hα emission sources brighter than V∼21 have been identified in
the region. More than half of these are concentrated in IC 1274 and
are presumably members of a faint T Tauri star population. Chandra
Advanced CCD Imaging Spectrometer imaging of a nearby suspected pulsar
and time-variable γ-ray source (GeV J1809-2327) detected 21
X-ray sources in the cluster vicinity, some of which are coincident
with the early-type stars and Hα emitters in IC 1274. Deep
(V∼22) optical BVRI photometry has been obtained for the cluster
region. A distance of 1.82±0.3kpc and a mean extinction of
AV∼1.21±0.2mag follow from photometry of the early-type stars. Using
pre-main-sequence evolutionary models, we derive a median age for the
Hα emitters and X-ray sources of ∼1Myr; however, a significant
dispersion is present. The displaced material was driven against what
remains of the molecular cloud to the east, enabling the formation of
the substantial number of T Tauri stars found there. A dispersed
population of Hα emitters is also found along the periphery of
L227, IC 1275, and IC 4684.
Description:
Deep optical BVRI (Bessel) images of IC 1274 were obtained on the
night of 2006 August 31 using the LFC (Large Format Camera) mounted at
the prime focus of the Hale 5m telescope at Palomar Observatory. The
LFC is a mosaic of six SITe 2048*4096 pixel thinned.
The Hα emission surveys of the IC 1274 region were carried out
on 1990 September 14, 2003 October 2-3, and 2009 July 17 UT. The 1990
and 2003 surveys were made with the Wide-Field Grism Spectrograph
(WFGS) installed at the f/10 Cassegrain focus of the UH 2.2 m
telescope. The 2009 survey used the Wide-Field Grism Spectrograph 2
(WFGS2; Uehara et al., 2004SPIE.5492..661U 2004SPIE.5492..661U), also installed at the
Cassegrain focus of the UH 2.2m telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 99 82 Hα emission stars in the IC 1274 region
table5.dat 31 56 Derived properties of the Hα emission
stars in the IC 1274 region
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See also:
II/281 : 2MASS 6X Point Source Working Database / Catalog (Cutri+ 2006)
J/ApJ/497/736 : The young cluster IC 348. (Herbig, 1998)
J/AJ/123/304 : BV(RI)CJHK Hα photometry in IC 5146 (Herbig+, 2002)
J/AJ/128/1233 : LkHα101 and the young cluster in NGC 1579 (Herbig+, 2004)
J/AJ/129/829 : Hα emission stars in NGC 2264 (Dahm+, 2005)
J/AJ/130/1805 : Hα emission stars in NGC 2362 (Dahm+, 2005)
J/AJ/131/1530 : Hα emission stars in LDN988 (Herbig+, 2006)
J/AJ/143/03 : Hα emission stars in IC 1274 (Dahm+, 2012)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- IHa [686/762]? IHα number (1)
5- 6 I2 h RAh Hour of Right Ascension (J2000)
8- 9 I2 min RAm Minute of Right Ascension (J2000)
11- 15 F5.2 s RAs Second of Right Ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Degree of Declination (J2000)
21- 22 I2 arcmin DEm Arcminute of Declination (J2000)
24- 27 F4.1 arcsec DEs Arcsecond of Declination (J2000)
29- 33 F5.2 mag Vmag [11.81/21.06]? The V band magnitude (2)
35 A1 --- f_Vmag Literature V magnitude (3)
37- 40 F4.2 mag V-R [0.52/1.79]? The (V-R) color (2)
42- 45 F4.2 mag V-I [1.47/3.66]? The (V-I) color (2)
47- 50 F4.2 mag J-H [0.17/1.75]? The (J-H) color (4)
52- 55 F4.2 mag H-Ks [0.12/1.08]? The (H-Ks) color (4)
57- 62 F6.3 mag Ksmag [8.152/13.56]? The Ks band magnitude (4)
64- 66 I3 0.1nm W(Ha)1 [-86/-2]? Hα equivalent width
(1990 survey) (5)
67- 68 A2 --- u_W(Ha)1 [:/EM/ND/ ] Uncertainty flag on W(Ha)1 (6)
70- 73 I4 0.1nm W(Ha)2 [-189/-2]? Hα equivalent width
(2003 survey) (5)
74- 75 A2 --- u_W(Ha)2 [:/EM/ND/ ] Uncertainty flag on W(Ha)2 (6)
77- 80 I4 0.1nm W(Ha)3 [-328/-2]? Hα equivalent width
(2009 survey) (5)
81- 83 A3 --- u_W(Ha)3 [:/EM/EM?/ND/ ] Uncertainty flag on W(Ha)3 (6)
85- 99 A15 --- Note Comments
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Note (1): IHα number unless previously identified by
Herbig (1957ApJ...125..654H 1957ApJ...125..654H).
Note (2): Optical photometry from the LFC (Large Format Camera), unless
otherwise noted (see Note (3)).
Note (3): Flags as follows:
e = V-band magnitude from the literature.
f = Optical photometry from the literature.
Note (4): Near-infrared photometry from the 2MASS Point Source Catalog
(2006, Cat. II/281).
Note (5): From WFGS (Wide-Field Grism Spectrograph ; 1990 & 2003 surveys) or
WFGS2 (2009 survey) spectroscopy.
Note (6): Uncertainty as follows:
: = uncertain;
EM = emission detected, but not measurable because of faint continuum,
overlapping spectra, etc;
ND = emission not detected;
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- IHa [695/757] IHa number (IfAHA NNN in Simbad) (1)
5- 6 A2 --- SpT Spectral type (1)
8- 11 F4.2 Lsun L [0.31/9.65] Luminosity (1)
13- 16 F4.2 Rsun R [1.2/5.59] Radius (1)
18- 21 I4 K Teff [2985/4986] Effective temperature (1)
23- 26 F4.2 Msun M [0.19/1.55] Mass (1)
28- 31 F4.2 [yr] Age [4.58/6.84] log (Age) (1)
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Note (1): Predicted stellar properties from the models of Siess et al.
(2000A&A...358..593S 2000A&A...358..593S) for an assumed distance of 1.82kpc and an
average extinction of AV=1.21mag.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 26-Mar-2013