J/ApJ/942/22 Brackett emission lines in young star APOGEE sp. (Campbell+, 2023)
Pre-main-sequence Brackett emitters in the APOGEE DR17 catalog: line strengths
and physical properties of accretion columns.
Campbell H., Khilfeh E., Covey K.R., Kounkel M., Ballantyne R., Corey S.,
Roman-Zuniga C.G., Hernandez J., Martinez E.M., Ramirez K.P.,
Roman-Lopes A., Stassun K.G., Stringfellow G.S., Borissova J.,
Chojnowski S.D., Ramirez-Preciado V., Kim J.S., Serna J., Stutz A.M.,
Lopez-Valdivia R., Suarez G., Ybarra J.E., Longa-Pena P.,
Fernandez-Trincado J.G.
<Astrophys. J., 942, 22 (2023)>
=2023ApJ...942...22C 2023ApJ...942...22C
ADC_Keywords: Spectra, infrared; Surveys; YSOs; Equivalent widths
Keywords: Accretion ; Stellar accretion ; Pre-main sequence stars ;
Be stars ; Classical T Tauri stars ; Emission line stars
Abstract:
Very young (t≲10Myr) stars possess strong magnetic fields that
channel ionized gas from the interiors of their circumstellar disks to
the surface of the star. Upon impacting the stellar surface, the
shocked gas recombines and emits hydrogen spectral lines. To
characterize the density and temperature of the gas within these
accretion streams, we measure equivalent widths of Brackett (Br)11-20
emission lines detected in 1101 APOGEE spectra of 326 likely
pre-main-sequence accretors. For sources with multiple observations,
we measure median epoch-to-epoch line strength variations of 10% in
Br11 and 20% in Br20. We also fit the measured line ratios to
predictions of radiative transfer models by Kwan & Fischer. We find
characteristic best-fit electron densities of ne=1011-1012cm-3,
and excitation temperatures that are inversely correlated with
electron density (from T∼5000K for ne∼1012cm-3 to T∼12500K at
ne∼1011cm-3). These physical parameters are in good agreement
with predictions from modeling of accretion streams that account for
the hydrodynamics and radiative transfer within the accretion stream.
We also present a supplementary catalog of line measurements from
9733 spectra of 4255 Brackett emission-line sources in the APOGEE Data
Release 17 data set.
Description:
We analyze high-resolution (R∼22500) near-IR (NIR; 1.51-1.70um)
spectra taken with the 300-fiber APOGEE spectrograph on the Sloan 2.5m
telescope at Apache Point and Las Campanas Observatories. To generate
a comprehensive, uniform, and complete catalog of Brackett emission
sources, we process the full contents of the Sloan Digital Sky Survey
(SDSS)-IV Data Release 17 (Abdurro'uf+ 2022, III/286). The APOGEE Data
Release 17 (DR17) data set includes all previously released APOGEE and
APOGEE-2 spectra; in total, the data set contains 2,659,178 individual
spectra, all of which have been re-reduced.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 431 9733 Line measurements for APOGEE DR17 Br11 emitters
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See also:
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
III/286 : APOGEE-2 DR17 final allStar catalog (Abdurro'uf+, 2022)
J/ApJ/794/125 : IN-SYNC. I. APOGEE stellar parameters (Cottaar+, 2014)
J/AJ/149/7 : SDSS-III/APOGEE. I. Be stars (Chojnowski+, 2015)
J/ApJ/799/136 : IN-SYNC. II. Candidate young stars in NGC 1333 (Foster+, 2015)
J/ApJ/818/59 : IN-SYNC. IV. YSOs in Orion A (Da Rio+, 2016)
J/AJ/151/144 : ASPCAP weights for 15 APOGEE chemical elements (Garcia+, 2016)
J/ApJS/236/27 : APOGEE-2 survey of Orion Complex (OSFC). I. (Cottle+, 2018)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/ApJ/893/56 : T Tauri star IR excesses & Ha EWs (Manzo-Martinez+, 2020)
J/ApJS/247/17 : Massive stars in APOGEE2 Survey. III. (Roman-Lopes+, 2020)
J/ApJ/914/28 : G305 star-forming region. II. Irregular var. (Medina+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- ID 2MASS Position-based Identifier
("2M" or "AP" HHMMSSss+DDMMSSs; J2000)
20- 24 I5 --- Plate [4914/12834] SDSS Plate ID
26- 30 I5 d MJD [55807/59234] Modified Julian Date of SDSS
observation (JD-2400000.5)
32- 34 I3 --- Fiber [1/300] SDSS Fiber ID
36- 45 F10.6 deg RAdeg Right Ascension, APOGEE DR17 (J2000)
47- 56 F10.6 deg DEdeg [-85/86] Declination, APOGEE DR17 (J2000)
58- 63 A6 --- Tel SDSS Telescope ID
65- 68 I4 --- Loc [-999/7251] SDSS Location ID
70- 88 A19 --- Field SDSS Field ID
90- 94 F5.2 0.1nm EWBr11-auto [0.75/27.4] Brackett 11 Scripted
Equivalent width, Angstroms
96- 100 F5.2 0.1nm e_EWBr11-auto [0/24] Uncertainty in EWBr11
102- 106 F5.2 0.1nm EWBr12-auto [0.38/36.08]? Brackett 12 Scripted
Equivalent width, Angstroms
108- 112 F5.2 0.1nm e_EWBr12-auto [0.05/20]? Uncertainty in EWBr12
114- 118 F5.2 0.1nm EWBr13-auto [-1.62/21]? Brackett 13 Scripted
Equivalent width, Angstroms
120- 123 F4.2 0.1nm e_EWBr13-auto [0.05/9]? Uncertainty in EWBr13
125- 129 F5.2 0.1nm EWBr14-auto [-2.6/26.23]? Brackett 14 Scripted
Equivalent width, Angstroms
131- 135 F5.2 0.1nm e_EWBr14-auto [0.05/16]? Uncertainty in EWBr14
137- 141 F5.2 0.1nm EWBr15-auto [-2.3/21]? Brackett 15 Scripted Equivalent
width, Angstroms
143- 146 F4.2 0.1nm e_EWBr15-auto [0.06/8.5]? Uncertainty in EWBr15
148- 152 F5.2 0.1nm EWBr16-auto [-3.3/17.5]? Brackett 16 Scripted
Equivalent width, Angstroms
154- 158 F5.2 0.1nm e_EWBr16-auto [0.06/17.1]? Uncertainty in EWBr16
160- 164 F5.2 0.1nm EWBr17-auto [-0.96/21]? Brackett 17 Scripted
Equivalent width, Angstroms
166- 170 F5.2 0.1nm e_EWBr17-auto [0.06/10.3]? Uncertainty in EWBr17
172- 176 F5.2 0.1nm EWBr18-auto [-2.2/14.4]? Brackett 18 Scripted
Equivalent width, Angstroms
178- 181 F4.2 0.1nm e_EWBr18-auto [0.07/10]? Uncertainty in EWBr18
183- 187 F5.2 0.1nm EWBr19-auto [-5.71/10.6]? Brackett 19 Scripted
Equivalent width, Angstroms
189- 192 F4.2 0.1nm e_EWBr19-auto [0.07/10]? Uncertainty in EWBr19
194- 198 F5.2 0.1nm EWBr20-auto [-3.5/10.3]? Brackett 20 Scripted
Equivalent width, Angstroms
200- 204 F5.2 0.1nm e_EWBr20-auto [0.07/14]? Uncertainty in EWBr20
206 I1 --- YCFlag [0/1] 1=Source is in the Young Cluster
sample
208- 211 F4.1 cm-3 YCEdens [8/12.4]? Electron Density of Best Fit
Model to Brackett Decrement (1)
213- 216 F4.1 cm-3 B_YCEdens [10.4/12.4]? Maximum Electron Density (1)
218- 221 F4.1 cm-3 b_YCEdens [8/12.2]? Minimum Electron Density (1)
223- 226 F4.2 cm-3 e_YCEdens [0.08/1.7]? Standard Deviation of Electron
Densities (1)
228- 232 I5 K YCGasT [3750/15000]? Gas Temperature of Best Fit
Model to Brackett Decrement (1)
234- 238 I5 K B_YCGasT [12500/15000]? Maximum Gas Temperature (1)
240- 244 I5 K b_YCGasT [3750/10000]? Maximum Gas Temperature (1)
246- 249 I4 K e_YCGasT [1768/4086]? Standard Deviation of Gas
Temperature (1)
251- 256 F6.2 --- chisq [0/104]? Chi Square of Best Fit Model to
Brackett Decrement (1)
258- 261 F4.2 --- e_chisq [2.3]? Standard Deviation of Chi Square
values for fits (1)
263- 267 F5.2 --- slope [-0.9/4.1] Ratio of continuum fluxes near
the Br 11 and Br 20 lines (2)
269 I1 --- FeII [0/3] FeII emission flag (3)
271 I1 --- NN-Det [0/1] Neural Net Classification, Br Line
Detection (1=line detected;
0=no line detected)
273 I1 --- NN-Dble [0/1] Neural Net Classification, Br Line
Profiles (1=double peaked profile;
0=single peak profile)
275 I1 --- NN-Neb [0/1] Neural Net Classification, Br Line
Width (1=narrow/ISM width;
0=Doppler broadened profile)
277 I1 --- NN-Good [0/1] Neural Net Classification, Br Line
Quality (1=Good; 0=Bad)
279- 284 F6.1 km/s RVelBr-NN [-176/297]? Neural Net Estimate, Br Line
Center Velocities
286- 289 F4.1 km/s e_RVelBr-NN [1.4/100]? Neural Net Estimate, Uncertainty
in Br Line Center Velocities
291- 296 F6.1 km/s DVBr-NN [90/1332]? Neural Net Estimate, Velocity
Width of Br Line Profiles
298- 303 F6.2 km/s e_DVBr-NN [1/354]? Neural Net Estimate, Uncertainty
in Br Line Velocity Width
305- 306 I2 --- MaxBr [11/20]?=0 Highest order Brackett line
detected by the Neural Net analysis
308- 312 F5.2 0.1nm EWBr11-nn [0.14/84.55] Brackett 11 Neural Net
Equivalent width, Angstroms
314- 318 F5.2 0.1nm e_EWBr11-nn [0/53] Uncertainty in EWBr11
320- 325 F6.2 0.1nm EWBr12-nn [0.27/225] Brackett 12 Neural Net
Equivalent width, Angstroms
327- 331 F5.2 0.1nm e_EWBr12-nn [0/27.2] Uncertainty in EWBr12
333- 338 F6.2 0.1nm EWBr13-nn [0.13/121.3] Brackett 13 Neural Net
Equivalent width, Angstroms
340- 344 F5.2 0.1nm e_EWBr13-nn [0/18] Uncertainty in EWBr13
346- 351 F6.2 0.1nm EWBr14-nn [0.2/116] Brackett 14 Neural Net
Equivalent width, Angstroms
353- 357 F5.2 0.1nm e_EWBr14-nn [0/22.1] Uncertainty in EWBr14
359- 363 F5.2 0.1nm EWBr15-nn [0.14/57.5] Brackett 15 Neural Net
Equivalent width, Angstroms
365- 369 F5.2 0.1nm e_EWBr15-nn [0/15.2] Uncertainty in EWBr15
371- 376 F6.2 0.1nm EWBr16-nn [0.14/223.5] Brackett 16 Neural Net
Equivalent width, Angstroms
378- 382 F5.2 0.1nm e_EWBr16-nn [0/19.4] Uncertainty in EWBr16
384- 388 F5.2 0.1nm EWBr17-nn [0.14/37.5] Brackett 17 Neural Net
Equivalent width, Angstroms
390- 394 F5.2 0.1nm e_EWBr17-nn [0/14] Uncertainty in EWBr17
396- 401 F6.2 0.1nm EWBr18-nn [0/156] Brackett 18 Neural Net Equivalent
width, Angstroms
403- 407 F5.2 0.1nm e_EWBr18-nn [0/46.5] Uncertainty in EWBr18
409- 413 F5.2 0.1nm EWBr19-nn [0/73] Brackett 19 Neural Net Equivalent
width, Angstroms
415- 419 F5.2 0.1nm e_EWBr19-nn [0/19.5] Uncertainty in EWBr19
421- 425 F5.2 0.1nm EWBr20-nn [0/96] Brackett 20 Neural Net Equivalent
width, Angstroms
427- 431 F5.2 0.1nm e_EWBr20-nn [0/20] Uncertainty in EWBr20
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Note (1): YC measurements are for sources on Young Cluster plates. Minimum,
maximum, and standard deviation measurements, including for χ2,
correspond to all models within XX of minimum chi square.
Note (2): The slope is the ratio of continuum fluxes near the Br11 and Br20
lines, presented as Br11cont, Br20cont where values greater than 1
represent sources with SEDs rising to long wavelengths.
Note (3): FeII emission flag as follows:
1 = one FeII line detected;
2 = two velocity separated FeII lines detected;
0 = otherwise.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Nov-2024