J/PASJ/60/739 Emission-line stars in the W5E HII region (Nakano+, 2008)
Clustering of emission-line stars in the W5E H II region.
Nakano M., Sugitani K., Niwa T., Itoh Y., Watanabe M.
<Publ. Astron. Soc. Jap., 60, 739-748 (2008)>
=2008PASJ...60..739N 2008PASJ...60..739N
ADC_Keywords: H II regions ; Photometry, SDSS ; Equivalent widths
Keywords: ISM: H II regions - ISM: individual (W5) - stars: formation -
stars: pre-main-sequence
Abstract:
We have made a new survey of emission-line stars in the W5 E HII
region to investigate the population of PMS stars near the OB stars by
using the Wide Field Grism Spectrograph 2 (WFGS2). A total of 139 Halpha
emission stars were detected and their g'i'-photometry was performed.
Their spatial distribution shows three aggregates, i.e., two
aggregates near the bright-rimmed clouds at the edge of the W5 E HII
region (BRC 13 and BRC 14) and one near the exciting O7V star. The age
and mass of each Halpha star were estimated from an extinction-corrected
color-magnitude diagram and theoretical evolutionary tracks. We
found, for the first time in this region, that the young stars near
the exciting star are systematically older (4Myr) than those near the
edge of the HII region (1Myr). This result supports that the
formation of stars proceeds sequentially from the center of HII
region to the eastern bright rim. We further suggest a possibility
that the birth of low-mass stars near the exciting star of the HII
region precedes the production of massive OB stars in the pre-existing
molecular cloud.
Description:
The Halpha survey and the optical photometry of the region were
conducted in 2006 September 22 and 24. We used the Wide Field Grism
Spectrograph 2 (WFGS2) mounted on the University of Hawaii 2.2-m
telescope. The number of Hα-emission stars are:
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RA (2000) DE Designation(s) (Nb of Hα stars)
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03 01 09.9 +60 39 28.0 W5 E-a 16
03 01 38.2 +60 29 00.3 W5 E-b 45
03 00 16.9 +60 31 57.5 W5 E-c 52
02 59 23.0 +60 35 24.0 W5 E-d 40
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 95 139 Summary of Hα stars
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See also:
J/AJ/123/2597 : Halpha stars and HH objects near BRCs (Ogura+, 2002)
J/PASJ/58/L29 : JHK photometry of low-mass stars in BRC 14 (Matsuyanagi+, 2006)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [NSN2008] Sequential number
5- 10 A6 --- Name Name (1)
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 22 F5.2 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign (J2000)
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 34 F4.1 arcsec DEs Declination (J2000)
36- 38 F3.1 mag g'-i' ?=- g'-i' colour index
40- 43 F4.1 mag i'mag ?=- i' magnitude
45 A1 --- l_EW Limit flag on EW
46- 50 F5.1 0.1nm EW ?=- Hα equivalent width
52- 54 F3.1 mag AV ?=- Absorption in V band
56- 71 A16 --- 2MASS 2MASS name (HHMMSSss+DDMMSSs)
72 A1 --- q_2MASS [*] Good 2MASS quality flag (2)
74- 75 A2 --- Flag [wc] wc for weak continuum
77- 95 A19 --- Rem Other names (3)
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Note (1): Names as:
a-NNNN for W5 E-a region, [NSN2008] a-NNNN in Simbad
b-NNNN for W5 E-b region, [NSN2008] b-NNNN in Simbad
c-NNNN for W5 E-c region, [NSN2008] c-NNNN in Simbad
d-NNNN for W5 E-d region, [NSN2008] d-NNNN in Simbad
Note (2): the asterisk (*) indicates a good photometric quality
in all three bands (J,H,Ks)
Note (3): Other names as:
[OSP]NN-NN = Hα star from Ogura et al. (2002,
Cat. J/AJ/123/2597), [OSP2002] BRC NN NN in Simbad
[MIS]NN = YSO candidate from Matsuyanagi et al. (2006,
Cat. J/PASJ/58/L29), [MIS2006] NN in Simbad
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-Mar-2009