J/MNRAS/486/3473 Small star-forming region in MBM 110 (Sung+, 2019)
The Sejong Open cluster Survey (SOS) VI. A small star-forming region in the high
Galactic latitude molecular cloud MBM 110.
Sung H., Bessell M.S., Song I.
<Mon. Not. R. Astron. Soc., 486, 3473-3487 (2019)>
=2019MNRAS.486.3473S 2019MNRAS.486.3473S (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Stars, pre-main sequence ; Optical ;
Positional data ; Magnitudes ; Parallaxes, trigonometric ;
Proper motions ; Molecular clouds
Keywords: stars: formation - stars: pre-main-sequence -
open clusters and associations: individual (MBM 110)
Abstract:
We present optical photometric, spectroscopic data for the stars in
the high Galactic latitude molecular cloud MBM 110. For the complete
membership selection of MBM 110, we also analyse Wide-field Infrared
Survey Explorer (WISE) mid-infrared data and Gaia astrometric data.
Membership of individual stars is critically evaluated using the data
mentioned above. The Gaia parallax of stars in MBM 110 is
2.667±0.095mas (d=375±13pc), which confirms that MBM 110 is a
small star-forming region in the Orion-Eridanus superbubble. The age
of MBM 110 is between 1.9 and 3.1Myr depending on the adopted
pre-main-sequence evolution model. The total stellar mass of MBM 110
is between 16M☉ (members only) and 23M☉ (including
probable members). The star formation efficiency is estimated to be
about 1.4 per cent. We discuss the importance of such small star
formation regions in the context of the global star formation rate and
suggest that a galaxy's star formation rate calculated from the
Hα luminosity may underestimate the actual star formation rate.
We also confirm a young brown dwarf member based on photometry,
spectroscopy, and astrometry.
Description:
The number of near-infrared excess stars found in MBM 110 attracted an
optical imaging study of the region. We performed optical photometry
with the wide-field imager (WFI) of the 1m telescope at Siding Spring
Observatory (SSO) for a comprehensive study of YSOs in the region. In
2007 January, we obtained additional optical images of the central
region with the AZT-22 1.5m telescope at Maidanak Astronomical
Observatory (MAO), Uzbekistan. Based on the photometry, we selected
targets for spectroscopic observations - Hα emission stars and
stars in the PMS locus. For a complete census of YSOs in MBM 110 we
aimed to obtain medium resolution spectra for the stars with Hα
emission as well as for stars in the PMS locus using several
telescopes - Lick 3m telescope, Bohyun-san Optical Astronomy
Observatory (BOAO) 1.8m telescope, and SSO 2.3m telescope.
As optical photometry cannot provide a complete census of YSOs with
circumstellar disks, we downloaded WISE mid-infrared (MIR) data and
searched for Class I and II YSOs in the region. In addition, as
weak-line T Tauri stars (TTSs) may be missed in our Hα survey,
we searched for MIR excess emission stars and obtained their optical
spectra. We also searched for kinematic members using the Gaia Data
Release 2 (DR2) astrometric data (Gaia Collaboration
2018A&A...616A...1G 2018A&A...616A...1G, Cat. I/345).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 167 2052 Photometric data from SSO 1m WFI observation
table4.dat 143 798 Photometric data from MAO observations
table5.dat 131 43 Summary of membership selection
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/MNRAS/438/1451 : SOS II. UBVIHα photometry of IC 1848 (Lim+, 2014)
J/MNRAS/443/454 : SOS III. UBVIHα photometry in NGC 1893 (Lim+, 2014)
J/AJ/149/127 : SOS IV. NGC 1624 and NGC 1931 (Lim+, 2015)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- WFI
5- 8 I4 --- WFI WFI star ID (NNNN)
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 20 F5.2 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 32 F4.1 arcsec DEs Declination (J2000)
34- 39 F6.3 mag Imag Magnitude on the I-band
41- 46 F6.3 mag R-I ? R-I colour index
48- 53 F6.3 mag V-I ? V-I colour index
55- 60 F6.3 mag B-V ? B-V colour index
62- 67 F6.3 mag R-Ha ? R-Hα colour index
69- 73 F5.3 mag e_Imag Error on Imag
75- 79 F5.3 mag e_R-I ? Error on R-I
81- 85 F5.3 mag e_V-I ? Error on V-I
87- 91 F5.3 mag e_B-V ? Error on B-V
93- 97 F5.3 mag e_R-Ha ? Error on R-Ha
99 I1 --- o_Imag Number of observations used to obtain Imag
101 I1 --- o_R-I Number of observations used to obtain R-I
103 I1 --- o_V-I Number of observations used to obtain V-I
105 I1 --- o_B-V Number of observations used to obtain B-V
107 I1 --- o_R-Ha Number of observations used to obtain R-Ha
109-124 A16 --- OName 2MASS source designation (HHMMSSSS+DDMMSSS)
126 A1 --- Memb Membership (1)
128-167 A40 --- Remarks Remarks (2)
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Note (1): Membership as follows:
S = Hα emission star confirmed from spectroscopy
X = X-ray emission star
H = Hα emission star
h = Hα emission candidate
+ = X+H
L = X+h
n = Star with no Hα emission from spectroscopy
Note (2): Some remarks were truncated in the original pdf version
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name (M4kNNN)
8- 9 I2 h RAh Right ascension (J2000)
11- 12 I2 min RAm Right ascension (J2000)
14- 18 F5.2 s RAs Right ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 30 F4.1 arcsec DEs [] Declination (J2000)
32- 37 F6.3 mag Vmag Magnitude on the V-band
39- 43 F5.3 mag R-I ? R-I colour index
45- 49 F5.3 mag V-I ? V-I colour index
51- 55 F5.3 mag B-V ? B-V colour index
57- 62 F6.3 mag U-B ? U-B colour index
64- 69 F6.3 mag R-Ha ? R-Hα colour index
71- 75 F5.3 mag e_Vmag Error on Vmag
77- 81 F5.3 mag e_R-I ? Error on R-I
83- 87 F5.3 mag e_V-I ? Error on V-I
89- 93 F5.3 mag e_B-V ? Error on B-V
95- 99 F5.3 mag e_U-B ? Error on U-B
101-105 F5.3 mag e_R-Ha ? Error on R-Ha
107 I1 --- o_Vmag Number of observations used to obtain Vmag
109 I1 --- o_R-I Number of observations used to obtain R-I
111 I1 --- o_V-I Number of observations used to obtain V-I
113 I1 --- o_B-V Number of observations used to obtain B-V
115 I1 --- o_U-B Number of observations used to obtain U-B
117 I1 --- o_R-Ha Number of observations used to obtain R-Ha
119-122 I4 --- WFI ? WFI star ID
124-130 A7 --- Memb Membership (1)
132-137 F6.1 0.1nm WHa1 ? Hα equivalent width 1
139-143 F5.1 0.1nm WHa2 ? Hα equivalent width 2
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Note (1): Membership as follows:
X = X-ray emission star
x = X-ray emission candidate
H = Hα emission star
h = Hα emission candidate
+ = X+H
L = X+h
II = YSO Class II object
PM = proper motion member
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- WFI WFI star ID (NNNN)
6- 19 A14 --- OName Alternative name for the star
21 A1 --- SSO [HNh] Membership from SSO data (1)
23 A1 --- MAO [HNh] Membership from MAO data (1)
25- 31 F7.2 0.1nm WHa1 ? Hα equivalent width 1
33- 39 F7.2 0.1nm WHa2 ? Hα equivalent width 2
41 A1 --- f_WLi1 [*] Flag on WLi1 (2)
43- 46 F4.2 0.1nm WLi1 ? Li equivalent width 1
48- 51 F4.2 0.1nm WLi2 ? Li equivalent width 2
53- 56 F4.2 0.1nm e_WLi1 ? Error on WLi 1
58- 62 A5 --- SpType Spectral type
64- 71 A8 --- YSOclass YSO classification (3)
73- 78 F6.3 mas plx ? Parallax
80- 84 F5.3 mas e_plx ? Error on parallax
86 A1 --- Membpm [YN] MBM 110 membership from proper
motion (4)
88- 92 F5.2 --- ruwe ? Gaia DR2 renormalized unit weight error
94 A1 --- Memb [YNP] MBM 110 Membership (4)
96-131 A36 --- Remark Remarks (5)
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Note (1): Membership as follows:
H = Hα emission star
h = Hα emission candidate
N = Star with no Hα emission
Note (2): Flag as follows:
* = No Li absorption detected
Note (3): We adopted the YSO classification scheme in the WISE TCD of
Fischer et al. (2016ApJ...827...96F 2016ApJ...827...96F, Cat. J/ApJ/827/96)
Note (4): For the selection of members of MBM 110, we should take into account
the photometric data, spectroscopic characteristics, WISE MIR
information, parallax, and proper motions. The first criterion for
the membership is parallax. We restrict our attention to the stars
between plx=2.40-2.84mas, which covers most of the stars in the peak.
And then we consider the other four criteria - proper motion vector,
Hα emission from photometry, strong LiI λ6708Å
absorption, and/or Hα emission in the spectrum, and MIR excess
emission from WISE data. If a star meets at least two criteria from
among the four membership criteria, we classify the star as a member
of MBM 110. If a star meets two or more membership criteria mentioned
above, but the parallax of a star is smaller or larger than the range
mentioned above we consider this star as a probable member of MBM 110.
If a star meets the membership criteria based on astrometry alone
(parallax and proper motion), we consider the star as a possible
member of MBM 110. We cannot exclude the possibility that some young
stars are in the foreground or background of MBM 110, which is the
member of the Orion OB1a association or the Orion-Eridanus
superbubble.
Note (5): OEBM = Orion-Eridanus bubble member?
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History:
From electronic version of the journal
References:
Lim et al., Paper I 2011JKAS...44...39L 2011JKAS...44...39L
Lim et al., Paper II 2014MNRAS.438.1451L 2014MNRAS.438.1451L, Cat. J/MNRAS/438/1451
Lim et al., Paper III 2014MNRAS.443..454L 2014MNRAS.443..454L, Cat. J/MNRAS/443/454
Lim et al., Paper IV 2015AJ....149..127L 2015AJ....149..127L, Cat. J/AJ/149/127
Lim et al., Paper V 2015JKAS...48..343L 2015JKAS...48..343L
Sung et al., Paper VI 2019MNRAS.486.3473S 2019MNRAS.486.3473S
(End) Ana Fiallos [CDS] 24-Oct-2022