J/AJ/159/153 Optical and IR photometry in the HII region Sh2-242 (Panja+, 2020)
Census of the young stellar population in the galactic H II region Sh2-242.
Panja A., Mondal S., Dutta S., Joshi S., Lata S., Das R.
<Astron. J., 159, 153 (2020)>
=2020AJ....159..153P 2020AJ....159..153P
ADC_Keywords: H II regions; Star Forming Region; YSOs; Stars, distances;
Photometry, UBVRI; Photometry, infrared; Photometry, H-alpha
Keywords: H II regions ; Infrared excess ; Star formation ;
Pre-main sequence stars ; Extinction
Abstract:
We present here identification and characterization of the young
stellar population associated with an active star-forming site
Sh2-242. We used our own new optical imaging and spectroscopic
observational data, as well as several archival catalogs, e.g.,
Pan-STARRS-1, Gaia-DR2, Isaac Newton Telescope Photometric H-Alpha
Survey (IPHAS), Wide-field InfraRed Camera, 2MASS, and Spitzer. Slit
spectroscopic results confirm the classification of the main ionizing
source BD+26980 as an early-type star of spectral type B0.5V. The
spectrophotometric distance of the star is estimated as
2.08±0.24kpc, which confirms the source as a member of the
cluster. An extinction map covering a large area (diameter ∼50') is
generated with H and K photometry toward the region. From the map,
three distinct locations of peak extinction complexes (AV∼7-17mag)
are identified for the very first time. Using the infrared color
excess, a total of 33 Class I and 137 Class II young objects are
classified within the region. The IPHAS photometry reveals
classification of 36 Hα emitting sources, which might be
class II objects. Among 36 Hα emitting sources, 5 are already
identified using infrared excess emission. In total, 201 young objects
are classified toward S242 from this study. The membership status of
the young sources is further windowed with the inclusion of parallax
from the Gaia DR2 catalog. Using the optical and infrared
color-magnitude diagrams, the young stellar objects are characterized
with an average age of ∼1Myr and masses in the range 0.1-3.0M☉.
Description:
Optical photometric data for B(360nm), V(550nm), and I(900nm) bands
were acquired with the 1.3m Devasthal Fast Optical Telescope (DFOT),
Nainital, India, with different exposure times, on 2016 Dec 19.
Optical slit spectroscopic observations for five bright sources within
the region were carried out on 2016 Nov 03 and 2017 Jan 23, using the
Himalaya Faint Object Spectrograph and Camera on the 2m Himalayan
Chandra Telescope (HCT). Spectra were taken with Grism 7 (380-684nm)
and Grism 8 (580-830nm) with resolutions of 1330 and 2190, respectively.
Slitless spectroscopic data were obtained from the HCT to detect
Hα emission line stars toward the region on 2017 Dec 15. The
data were acquired using a broadband Hα filter (630-674nm) in
combination with Grism 5 (520-1030nm) in slitless mode.
As a complementary data set to the observed optical photometry, we
used optical/NIR imaging from the Panoramic Survey Telescope and Rapid
Response System 1 (Pan-STARRS-1 or PS1). The PS1 provides homogeneous
and deeper coverage photometry in five broad passbands gP1, rP1,
iP1, zP1, and yP1, ranging from 400 to 1000nm. The effective
wavelengths for the five filters are roughly 480, 620, 750, 870, and
960nm.
Archival data from Gaia DR2 (I/345), the Isaac Newton Telescope
(INT)/Wide Field Camera (WFC) Photometric Hα Survey of the
Northern Galactic Plane (IPHAS; Drew+ 2005MNRAS.362..753D 2005MNRAS.362..753D --see II/321),
the Wide-field InfraRed Camera (WIRCam) mounted at the 3.6m
Canada-France-Hawaii Telescope (CFHT --Proposal ID 06BF14 and 06BF96),
2MASS (II/246) and Spitzer were also obtained.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 123 5 Details of the spectroscopically observed stars
table5.dat 152 503 Photometric catalog of optically observed point
sources towards the S242 region
table6.dat 148 170 Photometric catalog of YSOs towards S242
table7.dat 117 36 Photometric catalog of Hα emitters towards
S242
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See also:
III/92 : A Library of Stellar Spectra (Jacoby+ 1984)
III/195 : Atlas of Optical Spectral Classification OB Stars (Walborn+, 1990)
II/183 : UBVRI Photometric Standards (Landolt 1992)
III/181 : Near Infrared Spectra of Normal Stars (Torres-Dodgen+ 1993)
III/179 : Southern MK Standards 5800-10200A (Danks+ 1994)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+, 2003)
II/321 : IPHAS DR2 Source Catalogue (Barentsen+, 2014)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/109/1379 : Praesepe & M 67 spectral standards (Allen+ 1995)
J/AJ/118/1043 : Herbig Ae/Be stars catalog (Herbst+, 1999)
J/AJ/120/333 : UBVRI and Hα in NGC 6530 (Sung+, 2000)
J/ApJ/581/1194 : Taurus-Auriga PMS stars ages and Teff (Palla+, 2002)
J/AJ/126/1916 : JHK photometry of young clusters near the Sun (Porras+,2003)
J/A+A/468/1009 : Star formation in Perseus. II. (Hatchell+, 2007)
J/ApJ/682/445 : Spitzer observations of S254-S258 (Chavarria+, 2008)
J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/720/679 : Optical spectroscopy in Cygnus X region (Beerer+, 2010)
J/ApJS/187/251 : Ultradeep Ks imaging in the GOODS-N (Wang+, 2010)
J/MNRAS/415/103 : IPHAS T Tauri candidates in IC 1396 (Barentsen+, 2011)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/MNRAS/432/3445 : YSOs on HII complex Sh2-252 (Jose+, 2013)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014)
J/ApJ/784/111 : Morph. of candidate intermediate-mass SFRs (Lundquist+,2014)
J/MNRAS/454/3597 : NGC 2282 BVI Ha observations (Dutta+, 2015)
J/ApJ/813/25 : YSO candidates in W49 observed with Spitzer (Saral+, 2015)
J/ApJ/839/108 : YSOs in the star-forming regions W51 & W43 (Saral+, 2017)
J/ApJ/864/154 : Planck cold clump G108.37-01.06 YSO candidates (Dutta+,2018)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Seq [1/5] Running sequence number
3- 4 I2 h RAh Hour of right ascension (J2000)
6- 7 I2 min RAm Minute of right ascension (J2000)
9- 13 F5.2 s RAs Second of right ascension (J2000)
15 A1 --- DE- Sign of declination (J2000)
16- 17 I2 deg DEd Degree of declination (J2000)
19- 20 I2 arcmin DEm Arcminute of declination (J2000)
22- 26 F5.2 arcsec DEs Arcsecond of declination (J2000)
28- 35 A8 --- SpT MK spectral types estimated from
the spectroscopic observations
37- 42 F6.3 mag Jmag [7.9/10.4] 2MASS J-band magnitude
44- 48 F5.3 mag e_Jmag [0.009/0.03] Jmag uncertainty
50- 55 F6.3 mag Hmag [7.309/10.007] 2MASS H-band magnitude
57- 61 F5.3 mag e_Hmag [0.019/0.057] Hmag uncertainty
63- 67 F5.3 mag Ksmag [7.065/9.868] 2MASS Ks-band magnitude
69- 73 F5.3 mag e_Ksmag [0.009/0.023] Ksmag uncertainty
75- 78 F4.2 mag Av [0.24/3.28] Visual extinction (1)
80- 83 F4.2 mag e_Av [0.02/0.06] Av uncertainty
85- 89 F5.2 mag DM [6.19/11.58]? Distance modulus (1)
91- 94 F4.2 mag e_DM [0.04/0.05]? DM uncertainty
96- 99 I4 pc Dist [173/2076]? Spectroscopic distance of the star
101-103 I3 pc e_Dist [16/239]? Dist uncertainty
105-108 I4 pc GDist [769/2764] Distance from Gaia DR2 (I/345)
110-112 I3 pc e_GDist [32/506] GDist uncertainty
114-123 A10 --- Mm Membership
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Note (1): Visual extinction (AV) and distance modulus are calculated
from spectral types and infrared photometry.
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq [1/503] Running sequence number of the source
6- 14 F9.6 deg RAdeg [87.83/88.16] Right Ascension (J2000)
16- 24 F9.6 deg DEdeg [26.88/27.18] Declination (J2000)
26- 32 F7.3 mag Vmag [10/20]?=999 Apparent V band magnitude (1)
34- 40 F7.3 mag e_Vmag [0.003/0.2]?=999 Uncertainty in Vmag
42- 48 F7.3 mag B-V [0.29/3.2]?=999 The (B-V) color index (1)
50- 56 F7.3 mag e_B-V [0.004/0.4]?=999 Uncertainty in B-V
58- 64 F7.3 mag V-I [0.3/3.7]?=999 The (V-I) color index (1)
66- 72 F7.3 mag e_V-I [0.004/0.2]?=999 Uncertainty in V-I
74- 80 F7.3 mag Jmag [7.9/16.6]?=999 Apparent J band magnitude (G1)
82- 88 F7.3 mag e_Jmag [0.009/0.3]?=999 Uncertainty in Jmag
90- 96 F7.3 mag Hmag [7.3/16]?=999 Apparent H band magnitude (G1)
98-104 F7.3 mag e_Hmag [0.01/0.3]?=999 Uncertainty in Hmag
106-112 F7.3 mag Kmag [7/15.7]?=999 Apparent K band magnitude (G1)
114-120 F7.3 mag e_Kmag [0.009/0.3]?=999 Uncertainty in Kmag
122-128 F7.3 mag 3.6mag [6.8/15.5]?=999 Spitzer/IRAC 3.6µm band
apparent magnitude (G2)
130-136 F7.3 mag e_3.6mag [0.01/0.2]?=999 Uncertainty in 3.6mag
138-144 F7.3 mag 4.5mag [6.9/15.5]?=999 Spitzer/IRAC 4.5µm band
apparent magnitude (G2)
146-152 F7.3 mag e_4.5mag [0.02/0.1]?=999 Uncertainty in 4.5mag
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Note (1): Photometric magnitudes, colors, and their errors from
the 1.3 m Devasthal Fast Optical Telescope (DFOT).
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Class Source class type ("I", 33 young objects; or
"II", 137 young objects)
4- 6 I3 --- Seq [1/137] Running sequence number of the source
(1-33 for Class I objects and
1-137 for Class II objects)
8- 16 F9.6 deg RAdeg [87.66/88.28] Right Ascension (J2000)
18- 26 F9.6 deg DEdeg [26.77/27.43] Declination (J2000)
28- 34 F7.3 mag gmag [14/29.8]?=999 PS1 (II/349) apparent g band
AB magnitude
36- 42 F7.3 mag e_gmag [0.003/0.3]?=999 Uncertainty in gmag
44- 50 F7.3 mag ymag [12.7/20.1]?=999 PS1 (II/349) apparent y band
AB magnitude
52- 58 F7.3 mag e_ymag [0.002/0.3]?=999 Uncertainty in ymag
60- 66 F7.3 mag Jmag [12/20.5]?=999 Apparent J band magnitude (G1)
68- 74 F7.3 mag e_Jmag [0.01/0.5]?=999 Uncertainty in Jmag
76- 82 F7.3 mag Hmag [11/18.4]?=999 Apparent H band magnitude (G1)
84- 90 F7.3 mag e_Hmag [0.01/0.2]?=999 Uncertainty in Hmag
92- 98 F7.3 mag Kmag [10/16.8]?=999 Apparent K band magnitude (G1)
100-106 F7.3 mag e_Kmag [0.009/0.1]?=999 Uncertainty in Kmag
108-114 F7.3 mag 3.6mag [9/17]?=999 Spitzer/IRAC 3.6µm band
apparent magnitude (G2)
116-122 F7.3 mag e_3.6mag [0.02/0.2]?=999 Uncertainty in 3.6mag
124-130 F7.3 mag 4.5mag [8.6/16.4]?=999 Spitzer/IRAC 4.5µm band
apparent magnitude (G2)
132-138 F7.3 mag e_4.5mag [0.01/0.2]?=999 Uncertainty in 4.5mag
140-143 I4 pc Dist [163/4869]?=999 Gaia DR2 catalog (I/345) distance
145-148 I4 pc e_Dist [5/4948]?=999 Uncertainty in Dist
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/36] Running sequence number of the source
5- 13 F9.6 deg RAdeg [87.65/88.3] Right Ascension (J2000)
15- 23 F9.6 deg DEdeg [26.69/27.43] Declination (J2000)
25- 29 F5.2 mag rmag [15.49/19.93]?=999 IPHAS DR2 (II/321) apparent
r-band magnitude
31- 34 F4.2 mag e_rmag [0/0.09]?=999 Uncertainty in rmag
36- 40 F5.2 mag imag [14.88/19.4]?=999 IPHAS DR2 (II/321) apparent
i-band magnitude
42- 45 F4.2 mag e_imag [0/0.06]?=999 Uncertainty in imag
47- 51 F5.2 mag Hamag [14.93/19.25]?=999 IPHAS DR2 apparent
Hα band magnitude
53- 56 F4.2 mag e_Hamag [0/0.07]?=999 Uncertainty in Hamag
58- 64 F7.3 mag Jmag [13.6/17.4]?=999 Apparent J band magnitude (G1)
66- 72 F7.3 mag e_Jmag [0.02/0.2]?=999 Uncertainty in Jmag
74- 80 F7.3 mag Hmag [12/16.5]?=999 Apparent H band magnitude (G1)
82- 88 F7.3 mag e_Hmag [0.02/0.2]?=999 Uncertainty in Hmag
90- 96 F7.3 mag Kmag [10.9/16.3]?=999 Apparent K band magnitude (G1)
98-104 F7.3 mag e_Kmag [0.02/0.3]?=999 Uncertainty in Kmag
106-109 I4 pc Dist [89/5615]?=999 Gaia DR2 catalog (I/345) distance
111-114 I4 pc e_Dist [2/3092]?=999 Uncertainty in Dist
116-117 A2 --- Class Source class type ("II": 5 objects; or class I)
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Global notes:
Note (G1): From WIRCam (Puget+, 2004SPIE.5492..978P 2004SPIE.5492..978P --see
the "Description" section) or from 2MASS PSC (See Cat. II/246).
Note (G2): From Spitzer IRAC photometric catalog (Fazio+, 2004ApJS..154...10F 2004ApJS..154...10F).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 07-May-2020