J/ApJ/889/50 Young stars near CG30 in the Gum Nebula (Yep+, 2020)
Young stars near cometary globule CG 30 in the tumultuous Gum Nebula.
Yep A.C., White R.J.
<Astrophys. J., 889, 50 (2020)>
=2020ApJ...889...50Y 2020ApJ...889...50Y
ADC_Keywords: Stars, pre-main sequence; Radial velocities; Spectral types;
Stars, ages; Equivalent widths; Rotational velocities
Keywords: Young star clusters ; Cometary globules ; Stellar accretion disks ;
Protoplanetary disks ; Pre-main sequence ; Pre-main sequence stars ;
Fundamental parameters of stars ; Low mass stars ; Stellar accretion ;
Stellar properties ; Accretion ; Star forming regions
Abstract:
We have conducted a high-dispersion (R∼34000) optical spectroscopic
study of 10 young stars near the cometary globule CG 30 in the
Gum Nebula, a diffuse HII region home to at least 32 cometary
globules. All 10 spectroscopically observed stars at the nebula's
northern edge are of low mass (spectral types M4.5-K5), have broad
Hα emission, and show spectral veiling. Eight of the 10 are
classical T Tauri stars. We spectroscopically measure the photospheric
properties of CG 30 IRS 4 inside CG 30. Though embedded, CG 30 IRS 4
is T Tauri-like, with relatively slow projected rotation and moderate
veiling. Undepleted Li absorptions, strong Hα emissions, and
positions well above the main sequence on an H-R diagram suggest that
the 10 stars are ≲1Myr old. Using our measurements, previous
spectroscopy, and previous photometry of 11 other young stars in the
area, we determine stellar, kinematic, and accretion properties of a
total of 21 young stars. Shared radial velocities, proper motions,
distances, and ages suggest that 14 of the young stars (including
CG 30 IRS 4) are kinematically related to CG 30. From Gaia DR2
distances to six of these stars, we derive a distance of 358.1±2.2pc
to the cometary globule complex CG 30/31/38. The CG 30 association has
an accretor fraction of 29%±14%, low for quiescent clusters of
similar age but consistent with other irradiated clusters. The
Gum Nebula's moderate radiation environment (G0=6.6-2.7+3.2 at
CG 30) may be strong enough to shorten disk lifetimes.
Description:
We observed 9 young stars from Pettersson (1987A&A...171..101P 1987A&A...171..101P) and
CG 30 IRS 4 using the High-Resolution Echelle Spectrometer (HIRES)
on the W. M. Keck I telescope on 2003 February 17, 2003 February 18,
and 2004 April 4. We obtained one epoch for PHa 12, 14, 15, 21, 40,
44, and 51, two epochs for PHa 34, and three epochs for PHa 41 and
CG 30 IRS 4 with R∼34000 and a wavelength coverage of 6300-8750Å.
See Section 2.
For all photometrically examined 21 stars from
Pettersson (1987A&A...171..101P 1987A&A...171..101P), Neckel & Staude (1995ApJ...448..832N 1995ApJ...448..832N),
and Kim+ (2005AJ....129.1564K 2005AJ....129.1564K), we gather J, H, and K magnitudes from
2MASS. See Section 4.1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table13.dat 86 11 Basic properties (Table 1) and radial and
rotational velocitie (Table 3)
table2.dat 81 18 Equivalent widths
table4.dat 46 3 PHa 41 A and B velocities across 3 epochs
table5.dat 39 11 Veiling and spectral types
table67.dat 151 22 HR diagram parameters (Table 6) and
proper motions and radial velocities (Table 7)
table8.dat 55 15 Accretor fractions of star-forming regions
table9.dat 127 4 Hot star parameters
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See also:
B/pastel : The PASTEL catalogue (Soubiran+, 2016-)
II/224 : Catalogue of Stellar Diameters (CADARS) (Pasinetti-Fracassini+ 2001)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VII/216 : H-α emission regions in Southern Milky Way (Rodgers+ 1960)
J/A+A/297/391 : T Tauri stars ROSAT survey (Neuhaeuser+, 1995)
J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/A+A/331/581 : Rotation and activity in field M dwarfs (Delfosse+ 1998)
J/ApJS/141/503 : Radial Velocities for 889 late-type stars (Nidever+, 2002)
J/A+A/428/149 : Hipparcos parallaxes of O stars (Schroeder+, 2004)
J/AJ/130/188 : Young stars in Trumpler 37 & NGC 7160 (Sicilia-Aguilar+, 2005)
J/AJ/129/363 : Spectroscopy in Orion Nebula Cluster (Sicilia-Aguilar+, 2005)
J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)
J/ApJ/662/1067 : Sptizer observations of sigma Orionis (Hernandez+, 2007)
J/ApJS/207/5 : YSOs in LDN 1641 with Hectochelle spectra (Fang+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/A+A/559/A3 : Low-mass stars in Trumpler 37 (Sicilia-Aguilar+, 2013)
J/A+A/563/A94 : Kinematics of the Gamma Vel cluster (Jeffries+, 2014)
J/A+A/619/A155 : Open cluster kinematics with Gaia DR2 (Soubiran+, 2018)
J/AJ/157/85 : The CIDA Variability Survey of Orion OB1. II. (Briceno+, 2019)
J/A+A/621/A115 : Vela OB2 members (Cantat-Gaudin+, 2019)
J/A+A/626/A11 : Corona Australis ALMA and X-Shooter data (Cazzoletti+, 2019)
J/ApJ/870/32 : Kinematics in young star clusters & associations (Kuhn+, 2019)
Byte-by-byte Description of file: table13.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star Name
9 A1 --- m_Name Component for PHa 41 (1)
11- 12 I2 h RAh [8] 2MASS Hour of Right Ascension (J2000)
14- 15 I2 min RAm [8/15] Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs Second of Right Ascension (J2000)
23- 23 A1 --- DE- [-] 2MASS Sign of the Declination (J2000)
24- 25 I2 deg DEd [35/36] 2MASS Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 34 F5.2 arcsec DEs Arcsecond of Declination (J2000)
36- 40 A5 --- SpTl Spectral type
from Pettersson (1987A&A...171..101P 1987A&A...171..101P)
42- 47 F6.3 mag Vmag [14.3/16.55]? V band magnitude (2)
49- 53 F5.3 mag e_Vmag [0.029/1.1]? Uncertainty in Vmag (2)
55- 60 F6.3 mag Ksmag [8.9/12.1] 2MASS Ks band magnitude
62- 66 F5.3 mag e_Ksmag [0.019/0.05] Uncertainty in Ksmag
68- 72 F5.2 km/s HRV [21.9/33.7] Heliocentric radial velocity
74- 77 F4.2 km/s e_HRV [0.15/2] Uncertainty in HRV
79- 82 F4.1 km/s vsini [6.3/28] Rotational velocity
times the sin(inclination)
84- 86 F3.1 km/s e_vsini [0.2/2.7] Uncertainty in vsini
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Note (1): The reported HRV for PHα 41 A and B is the systemic velocity
of the pair (see text).
Note (2): Properties taken from Pettersson (1987A&A...171..101P 1987A&A...171..101P)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star Name (1)
9 A1 --- m_Name Component for PHa 41
11- 14 I4 yr Obs.Y [2003/2004] Observation date, year
16- 17 I2 "month" Obs.M Observation date, month
19- 20 I2 d Obs.D Observation date, day
22- 27 F6.1 0.1nm EWHaP87 [-130.5/-16.1]? Equivalent Width, LiI,
published in Pettersson (1987A&A...171..101P 1987A&A...171..101P)
29- 34 F6.2 0.1nm EWHaK05 [-26.6/-8.4]? Equivalent Width, LiI,
published in Kim+ 2005AJ....129.1564K 2005AJ....129.1564K
36- 40 F5.1 0.1nm EWHa [-83.0/-0.5] Equivalent Width, Hα,
this work
42- 45 F4.1 0.1nm e_EWHa [0.3/10] Uncertainty in EWHa
47- 47 A1 --- l_W10Ha Limit flag on W10Ha
49- 54 F6.2 0.1nm W10Ha [-13.6/-4.9] Hα emission profile,
10% peak height above continuum
56- 56 A1 --- l_W10Hav Limit flag on W10Hav
58- 61 F4.0 km/s W10Hav [225/621] Hα emission profile
63- 66 F4.2 0.1nm EWLiK05 [0.5/0.54]? Equivalent Width, LiI,
published in Kim+ 2005AJ....129.1564K 2005AJ....129.1564K
68- 71 F4.2 0.1nm e_EWLiK05 [0.04/0.06]? Uncertainty in EWLiK05
73- 76 F4.2 0.1nm EWLi [0.05/0.7] Equivalent Width, LiI, this work
78- 81 F4.2 0.1nm e_EWLi [0.01/0.82] Uncertainty in EWLi
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Note (1): Because the two Hα emission components cannot be resolved,
we give Hα emission values for the whole binary PHa 41.
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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- 8 F8.2 d MJD [52687.47/53099.35] Modified Julian Date
of observation (JD-2400000.5)
10- 14 F5.2 km/s HRVA [4.27/63.73] Heliocentric radial velocity,
Component A
16- 19 F4.2 km/s e_HRVA [0.19/0.5] Uncertainty in HRVA
21- 24 F4.1 km/s HRVB [-0.7/51.7] Heliocentric radial velocity,
Component B
26- 28 F3.1 km/s e_HRVB [1.3/1.5] Uncertainty in HRVB
30- 33 F4.1 km/s vsiniA [11.8/16.4] Rotational velocity
times the sin(inclination), Component A
35- 37 F3.1 km/s e_vsiniA [1.1/1.4] Uncertainty in vsiniA
39- 42 F4.1 km/s vsiniB [9.0/17.2] Rotational velocity
times the sin(inclination), Component B
44- 46 F3.1 km/s e_vsiniB [1.4/3.1] Uncertainty in vsiniB
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Star Name
9 A1 --- m_Name Component for PHa 41
11- 14 A4 --- SpT Best spectral type
16- 18 F3.1 --- e_SpT [0.5/1] Spectral type uncertainty, subclasses
20- 23 F4.2 --- r6500 [0.16/7.5] Veiling, 6500Å
25- 28 F4.2 --- e_r6500 [0.1/0.63] Uncertainty in r6500
30- 34 F5.3 --- r8400 [0/7.54] Veiling, 8400Å
36- 39 F4.2 --- e_r8400 [0.1/1.7] Uncertainty in r8400
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Byte-by-byte Description of file: table67.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 I1 --- Group [1/5] Group (1)
3- 3 A1 --- Flag [np] Derived properties flag (2)
5- 19 A15 --- Name Star Name
20 A1 --- m_Name Component for PHa 41
22- 25 F4.2 mag Av [0/2.3] Line of sight extinction, V band
27- 30 F4.2 mag e_Av [0.5/5]? Uncertainty in Av
32- 36 F5.2 mag delK [-0.2/1.3] Delta K band, infrared excess
38- 41 F4.2 mag e_delK [0.1/0.14]? Uncertainty in Av
43- 47 F5.2 mag mbol [10.9/16.3] bolometric magnitude
49- 52 F4.2 mag e_mbol [0.23/2.1]? Uncertainty in Av
54- 59 F6.1 pc Dist [155/7000] Distance
61- 66 F6.1 pc E_Dist [2.2/2800] Upper uncertainty on Dist
68- 73 F6.1 pc e_Dist [2.2/2000] Lower uncertainty on Dist
75- 79 F5.0 K Teff [3100/6510] Effective surface temperature
81- 84 F4.0 K E_Teff [20/690] Upper uncertainty on Teff
86- 89 F4.0 K e_Teff [50/590] Lower uncertainty on Teff
91- 95 F5.2 Lsun Lstar [0.02/76] Stellar luminosity, solar units
97-101 F5.2 Lsun E_Lstar [0.02/64]? Upper uncertainty on Lstar
103-107 F5.2 Lsun e_Lstar [0.02/48]? Lower uncertainty on Lstar
109-112 I4 pc DistIso [191/9536] Isochronal distance
114-119 F6.2 km/s HRV [-74.1/49.2]? Heliocentric radial velocity
121-124 F4.2 km/s e_HRV [0.15/3]? Uncertainty in HRV
126-132 F7.3 mas/yr pmRA [-22.95/-1.95]? Proper motion in Right Ascension
134-138 F5.3 mas/yr e_pmRA [0.05/4.8]? Uncertainty in pmRA
140-145 F6.3 mas/yr pmDE [0.5/21.21]? Proper motion in Declination
147-151 F5.3 mas/yr e_pmDE [0.05/4.7]? Uncertainty in pmDE
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Note (1): HR diagram grouping:
1 = CG 30 Association;
2 = CG 30 Association Candidates with Gaia DR2 Distances;
3 = CG 30 Association Candidates Assigned CG 30 Association Distance;
4 = Stars near PHa 41;
5 = Other stars.
Note (2): Derived properties flag as follows:
n = Distance are derived from negative parallaxes;
see Bailer-Jones+ (2018, I/347);
p = Distances and temperatures are assigned according to possible physical
association with another star or stars.
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 1 I1 --- Group [1/2] Group: 1=Quiescent or 2=Irradiated
3- 15 A13 --- Region Region
17- 18 A2 --- l_Age [~< ] Limit flags on Age
20- 22 F3.1 Myr b_Age [0.1/5]? Age range, minimum
24- 25 I2 Myr B_Age [1/10]? Age range, maximum
27- 31 A5 --- r_Age References for Age (1)
33- 35 I3 --- Nacc [1/159]? Number, accreting members
37- 39 I3 --- Ntot [14/450]? Number, total members
41- 41 A1 --- r_Ntot References for Nacc/Ntot (1)
43- 43 A1 --- u_frac [~] Uncertainty flag on frac
45- 48 F4.1 % frac [2/59] Accretor fraction
50- 53 F4.1 % e_frac [2/16]? Uncertainty for frac
55- 55 A1 --- r_frac [ce] References for frac (1)
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Note (1): References as follows:
a = Baraffe et al. (1998, J/A+A/337/403);
b = Siess et al. (2000A&A...358..593S 2000A&A...358..593S);
c = Mohanty et al. (2005ApJ...626..498M 2005ApJ...626..498M)
d = Sicilia-Aguilar et al. (2005, J/AJ/129/363),
(2005, J/AJ/130/188), (2013, J/A+A/559/A3)
e = Hernandez et al. (2007, J/ApJ/662/1067)
f = Dotter et al. (2008ApJS..178...89D 2008ApJS..178...89D);
g = Mortier et al. (2011MNRAS.418.1194M 2011MNRAS.418.1194M);
h = Fang et al. (2013, J/ApJS/207/5);
i = Biazzo et al. (2014A&A...572A..84B 2014A&A...572A..84B);
j = Baraffe et al. (2015A&A...577A..42B 2015A&A...577A..42B);
k = Cazzoletti et al. (2019, J/A+A/626/A11);
l = Winter et al. (2019MNRAS.490.5478W 2019MNRAS.490.5478W);
m = Briceno et al. (2019, J/AJ/157/85).
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Star Name
14- 18 I5 K Teff [35000/57000]? Stellar effective temperature
20- 20 A1 --- r_Teff [ai] Reference for Teff (1)
22- 25 F4.2 mag Umag [0.64/0.89]? U band magnitude
27- 27 A1 --- r_Umag [ci] Reference for Umag (1)
29- 32 F4.2 mag Bmag [1.58/1.98]? B band magnitude
34- 34 A1 --- r_Bmag [ci] Reference for Bmag (1)
36- 39 F4.2 mag Vmag [1.83/2.25]? V band magnitude
41- 41 A1 --- r_Vmag [ci] Reference for Vmag (1)
43- 46 F4.2 mag Avmag [0.13/0.51]? Extinction
48- 48 A1 --- r_Avmag [d] Reference for Avmag (1)
50- 52 I3 pc Dist [294/349] Distance
54- 55 I2 pc E_Dist [12/76] Upper uncertainty on Dist
57- 58 I2 pc e_Dist [11/50] Lower uncertainty on Dist
60- 60 A1 --- r_Dist [be] Reference for Dist (1)
62- 65 F4.1 Rsun Rstar [3.2/18.7]? Stellar radius, solar units
67- 69 F3.1 Rsun E_Rstar [2.3]? Upper uncertainty on Rstar
71- 73 F3.1 Rsun e_Rstar [1.9]? Lower uncertainty on Rstar
75- 75 A1 --- r_Rstar [af] Reference for Rstar (1)
77- 82 F6.2 km/s HRV [-23.9/15]? Heliocentric radial velocity
84- 86 F3.1 km/s e_HRV [2.9/3.1]? Uncertainty in HRV
88- 88 A1 --- r_HRV [g] Reference for HRV (1)
90- 95 F6.2 mas/yr pmRA [-29.71/-6]? Proper motion in Right Ascension
97-100 F4.2 mas/yr e_pmRA [0.08/0.3]? Uncertainty in pmRA
102-102 A1 --- r_pmRA [h] Reference for pmRA (1)
104-108 F5.2 mas/yr pmDE [10.43/16.68]? Proper motion in Declination
110-113 F4.2 mas/yr e_pmDE [0.09/0.32]? Uncertainty in pmDE
115-115 A1 --- r_pmDE [h] Reference for pmDE (1)
117-119 F3.1 --- G0 [0.5/3.7] Radiation environment
121-123 F3.1 --- E_G0 [0.1/2.7] Upper uncertainty in G0
125-127 F3.1 --- e_G0 [0.3/1.6] Lower uncertainty in G0
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Note (1): References as follows:
a = De Marco & Schmutz (1999A&A...345..163D 1999A&A...345..163D );
De Marco et al. (2000A&A...358..187D 2000A&A...358..187D);
b = Caraveo et al. (2001ApJ...561..930C 2001ApJ...561..930C);
c = Ducati (2002yCat.2237....0D 2002yCat.2237....0D);
d = Schroder et al. (2004A&A...428..149S 2004A&A...428..149S);
e = Apellaniz et al. (2008arXiv0804.2553M 2008arXiv0804.2553M);
f = Pasinetti Fracassini et al. (2001A&A...367..521P 2001A&A...367..521P);
g = Gontcharov (2006AstL...32..759G 2006AstL...32..759G);
h = Van Leeuwen (2007A&A...474..653V 2007A&A...474..653V);
i = Soubiran et al. (2016A&A...591A.118S 2016A&A...591A.118S).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Oct-2021