J/MNRAS/465/3039 Eruptive variable protostars from VVV EW (Contreras+, 2017)
Infrared spectroscopy of eruptive variable protostars from VVV.
Contreras Pena C., Lucas P.W., Kurtev R., Minniti D., Caratti o Garatti A.,
Marocco F., Thompson M.A., Froebrich D., Kumar M.S.N., Stimson W.,
Navarro Molina C., Borissova J., Gledhill T., Terzi R.
<Mon. Not. R. Astron. Soc., 465, 3039-3100 (2017)>
=2017MNRAS.465.3039C 2017MNRAS.465.3039C (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Stars, variable ; Equivalent widths ; Radial velocities
Keywords: stars: AGB and post-AGB - stars: low-mass - stars: pre-main-sequence -
stars: protostars - stars: variables - T Tauri - Herbig Ae/Be -
infrared: stars
Abstract:
In a companion work (Contreras Pena et al., 2017MNRAS.465.3011C 2017MNRAS.465.3011C, Paper
I), we detected a large population of highly variable Young Stellar
Objects (YSOs) in the Vista Variables in the Via Lactea (VVV) survey,
typically with class I or flat spectrum spectral energy distributions
and diverse light-curve types. Here we present infrared spectra
(0.9-2.5 µm) of 37 of these variables, many of them observed in a
bright state. The spectra confirm that 15/18 sources with eruptive
light curves have signatures of a high accretion rate, either showing
EXor-like emission features (Δv=2 CO, Brγ) and/or
FUor-like features (Δv=2 CO and H2O strongly in absorption).
Similar features were seen in some long-term periodic YSOs and faders
but not in dippers or short-term variables. The sample includes some
dusty Mira variables (typically distinguished by smooth Mira-like
light curves), two cataclysmic variables and a carbon star. In total,
we have added 19 new objects to the broad class of eruptive variable
YSOs with episodic accretion. Eruptive variable YSOs in our sample
that were observed at bright states show higher accretion luminosities
than the rest of the sample. Most of the eruptive variables differ
from the established FUor and EXor subclasses, showing intermediate
outburst durations and a mixture of their spectroscopic
characteristics. This is in line with a small number of other recent
discoveries. Since these previously atypical objects are now the
majority amongst embedded members of the class, we propose a new
classification for them as MNors. This term (pronounced emnor) follows
V1647 Ori, the illuminating star of McNeil's Nebula.
Description:
We present intermediate resolution IR spectra of 37 VVV high-amplitude
variable stars, 18 of which have eruptive LC classification
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 105 37 Characteristics of the spectroscopic sample
of VVV high-amplitude variables
table3.dat 88 40 Equivalent widths of common features found in
near-IR spectra of YSOs detected in our VVV sample
table4.dat 28 17 Radial velocities
table5.dat 52 23 Accretion luminosity from luminosity of the
Brγ line
tabled1.dat 93 37 Parameters derived from the Robitaille et al.
(2007ApJS..169..328R 2007ApJS..169..328R) models SED fitting
as explained in the text
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See also:
J/MNRAS/465/3011 : VVV high amplitude NIR variable stars (Contreras Pena+ 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- No Sequential number
4- 10 A7 --- VName Variable name (VVVvNNN,
[CLM2017] VVVvNNN in Simbad)
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- 35 F5.2 arcsec DEs Declination (J2000)
37- 41 F5.2 mag Jmag ?=- J magnitude
43- 46 F4.2 mag e_Jmag ?=- rms uncertainty on Jmag
48- 52 F5.2 mag Hmag ?=- H magnitude
54- 57 F4.2 mag e_Hmag ?=- rms uncertainty on Hmag
59- 63 F5.2 mag Ksmag ?=- Ks magnitude
65- 68 F4.2 mag e_Ksmag ?=- rms uncertainty on Ksmag
70- 73 F4.2 mag DKsmag Ksmax-Ksmin difference
75- 79 F5.2 -- alpha ?=- Slope of the SED, from Paper I
81- 83 F3.1 kpc dSFR ?=- likely distance to our objects estimated
from SIMBAD
85- 92 A8 --- Shape Shape, from Paper I
94-105 A12 --- Type Type, this paper (1)
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Note (1): non-er refers to YSOs not classified as eruptive variables.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Type Type
18- 24 A7 --- VName Object VName
25- 28 A4 --- n_VName Observation number
32- 37 F6.1 0.1nm EWH2 ?=- H2 (2.12um) equivalent width (1)
39- 42 F4.1 0.1nm e_EWH2 ?=- rms uncertainty on EWH2
44- 47 F4.1 0.1nm EWBrg ?=- Brγ (2.16um) equivalent width (1)
49- 51 F3.1 0.1nm e_EWBrg ?=- rms uncertainty on EWBrg
53- 56 F4.1 0.1nm EWNaI ?=- NaI (2.21um) equivalent width (1)
58- 60 F3.1 0.1nm e_EWNaI ?=- rms uncertainty on EWNaI
62- 64 F3.1 0.1nm EWCaI ?=- CaI (2.26um) equivalent width (1)
66- 68 F3.1 0.1nm e_EWCaI ?=- rms uncertainty on EWCaI
70- 74 F5.1 0.1nm EW12CO ?=- 12CO (2.293um) equivalent width (1) (2)
76- 79 F4.1 0.1nm e_EW12CO ?=- rms uncertainty on EW12CO
81- 84 F4.1 0.1nm EWMgI ?=- MgI (2.28um) equivalent width (1)
86- 88 F3.1 0.1nm e_EWMgI ?=- rms uncertainty on EWMgI
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Note (1): The EW is estimated by summing (1-Fi/Ci) over wavelength, where Fi and
Ci are the flux and the continuum at pixel i. This inevitably has fairly
large errors due to uncertainty in the continuum level, even though the
individual transitions are often very clearly detected.
Note (2): The EW of CO was measured in splot by visually selecting two
continuum points around the CO bandhead and estimating the continuum as a
linear function between the two points.
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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- 7 A7 --- VName Variable name
9- 14 F6.1 km/s Vlsr LSR velocity
16- 19 F4.1 km/s e_Vlsr rms uncertainty on Vlsr
21- 23 F3.1 kpc dnear ?=- Near distance
25- 28 F4.1 kpc dfar Far distance
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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- 12 A12 --- Type Type
14- 20 A7 --- VName Variable name
22- 31 A10 --- State Approximate state (from the LC) at which the
spectrum was taken
33- 36 F4.1 mag AKs Absorption in Ks band
37 A1 --- n_AKs Note on AKs (1)
39- 41 F3.1 kpc Dist Distance
42 A1 --- n_Dist Note on Distance (1)
44- 47 F4.1 Lsun Lacc1 Accretion luminosity from
Calvet et al. (2004AJ....128.1294C 2004AJ....128.1294C)
49- 52 F4.1 Lsun Lacc2 Accretion luminosity from
Muzerolle et al. (1998AJ....116.2965M 1998AJ....116.2965M)
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Note (1): Notes as follows:
c = Distance from SED fit
d = Distance from radial velocity
e = Distance from dSFR
f = Av from line ratios, see Appendix A
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Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Type Type
10- 16 A7 --- VName Variable name
18- 21 F4.1 Msun M* Stellar mass
23- 25 F3.1 Msun E_M* Error on M* (upper value)
27- 29 F3.1 Msun e_M* Error on M* (lower value)
31- 34 F4.1 [Msun/yr] logdMenv/dt ?=- Envelope infall rate
36- 38 F3.1 [Msun/yr] e_logdMenv/dt ? rms uncertainty on logdMenv/dt
40- 44 F5.1 [Msun/yr] logdMdisc/dt Disc mass accretion rate
46- 48 F3.1 [Msun/yr] e_logdMdisc/dt rms uncertainty on logdMdisc/dt
50- 52 F3.1 [yr] logAge Age
54- 56 F3.1 [yr] e_logAge rms uncertainty on Age
58- 60 F3.1 kpc Dist Distance to the system
62- 64 F3.1 kpc E_Dist Error on Dist (upper value)
66- 68 F3.1 kpc e_Dist Error on Dist (lower value)
70- 73 F4.1 [Lsun] logLbol Bolometric luminosity of the system
75- 77 F3.1 [Lsun] e_logLbol rms uncertainty on logLbol
79- 82 F4.2 --- chi2/N chi2 per data point of the
best-fitting model
84- 88 I5 --- Nfits Number of fits used to derive the
weighted mean values
90- 93 I4 --- Nfits2 Number of models which envelope
infall rate could be derived
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History:
From electronic version of the journal
References:
Contreras Pena et al., Paper I 2017MNRAS.465.3011C 2017MNRAS.465.3011C Cat. J/MNRAS/465/3011
(End) Patricia Vannier [CDS] 22-Nov-2018