J/ApJ/869/157 ASTRAL: reference spectra for evolved M stars (Carpenter+, 2018)
The Advanced Spectral Library (ASTRAL): reference spectra for evolved M stars.
Carpenter K.G., Nielsen K.E., Kober G.V., Ayres T.R., Wahlgren G.M., Rau G.
<Astrophys. J., 869, 157 (2018)>
=2018ApJ...869..157C 2018ApJ...869..157C
ADC_Keywords: Stars, M-type; Stars, giant; Stars, supergiant; Stars, late-type;
Stars, luminous; Spectra, ultraviolet; Energy distributions;
Radial velocities
Keywords: line: formation ; line: identification ; stars: atmospheres ;
stars: chromospheres ; stars: late-type ; stars: winds, outflows
Abstract:
The Hubble Space Telescope (HST) Treasury Program Advanced Spectral
Library Project: Cool Stars was designed to collect representative,
high-quality UV spectra of eight evolved F-M type cool stars. The
Space Telescope Imaging Spectrograph (STIS) echelle spectra of these
objects enable investigations of a broad range of topics, including
stellar and interstellar astrophysics. This paper provides a guide to
the spectra of the two evolved M stars, the M2 Iab supergiant
αOri and the M3.4 giant γCru, with comparisons to the
prototypical K1.5 giant αBoo. It includes identifications of the
significant atomic and molecular emission and absorption features and
discusses the character of the photospheric and chromospheric continua
and line spectra. The fluorescent processes responsible for a large
portion of the emission-line spectrum, the characteristics of the
stellar winds, and the available diagnostics for hot and cool plasmas
are also summarized. This analysis will facilitate the future study of
the spectra, outer atmospheres, and winds, not only of these objects
but of numerous other cool, low-gravity stars, for years to come.
Description:
This paper focuses on the evolved cool stars γCru and αOri
and compares their spectral characteristics to the well-studied
K1.5III star αBoo (Hinkle+ 2005uaas.book.....H 2005uaas.book.....H). The
observational strategy for α Ori and γ Cru, as for the
other objects in the ASTRAL Cool Star Program, was crafted to find the
optimal combination of spectral resolution and signal-to-noise over
the complete FUV and NUV spectra (1150-3159Å).
All of the HST Space Telescope Imaging Spectrograph (STIS) spectra
for the two objects are splined in a top-level data set covering the
entire wavelength region. An overview of the data used in this paper
is presented in Table 1, and a more detailed description of the data,
including the observing strategy, data reduction, coaddition, and
splicing, can be found on the Advances Spectral Library (ASTRAL)
website (http://casa.colorado.edu/~ayres/ASTRAL/)
and at the Mikulski Archive for Space Telescopes (MAST)
(http://archive.stsci.edu/prepds/astral/).
Objects:
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RA (ICRS) DE Designation(s) (Files)
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05 55 10.31 +07 24 25.4 alpha Ori = TYC 129-1873-1 (table9)
12 31 09.96 -57 06 47.6 gamma Cru = TYC 8654-3422-1 (table8)
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 57 12 HST/STIS ASTRAL observations for αOri and
γCru
table7.dat 83 460 Properties of fluorescent emission lines in STIS
spectra
table8.dat 95 333 Properties of chromospheric and wind lines in the
γCru ASTRAL spectrum
table9.dat 96 244 Properties of chromospheric and wind lines in the
αOri ASTRAL spectrum
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See also:
III/124 : Spectrophotometry of 60 stars (Kiehling, 1987)
III/186 : Energy distribution in stars at 320-760 nm (Knyazeva+, 1996)
J/A+A/177/131 : CaII & MgII excess flux density in cool stars (Rutten, 1987)
J/AZh/73/762 : Energy distribution giants & supergiants (Tereshchenko, 1996)
J/A+A/326/249 : Chromospheric models of dwarf M stars (Mauas+ 1997)
J/A+A/430/303 : MgII-K line fluxes cool active & quiet stars (Cardini+, 2005)
J/A+A/439/1137 : PHOENIX model chromospheres of M dwarfs (Fuhrmeister+, 2005)
J/A+A/469/309 : Chromospheric activity in late-type stars (Cincunegui+, 2007)
J/AJ/135/1117 : Spectroscopic study of red giants in M15 (Meszaros+, 2008)
J/A+A/514/A97 : High-resolution spectra Late-type stars (Lopez-Santiago+2010)
J/MNRAS/414/418 : Chromospheric Mg II h+k flux of evolved stars (Perez+, 2011)
J/MNRAS/471/770 : Parameters & IR excesses of Gaia DR1 stars (McDonald+, 2017)
J/A+A/616/A108 : Cool stars chromospheric activity (Boro Saikia+, 2018)
http://casa.colorado.edu/~ayres/ASTRAL/ : ASTRAL webpage
http://archive.stsci.edu/prepds/astral/ : MAST ASTRAL webpage
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Target Observed star (1)
11- 15 A5 --- Grating Instrument grating (E140M, E230M or E230H)
17- 20 I4 0.1nm lambda [1425/2762] Observation's wavelength
(λc) in Å units
22- 32 A11 arcsec Ap Size of aperture
34- 37 I4 0.1nm lam0 [1150/2865] Minimum spectral coverage
in Å units
39- 42 I4 0.1nm lam1 [1700/3118] Maximum spectral coverage
in Å units
44- 48 I5 s Exp [1862/17751] Exposition time
50- 57 F8.3 d JD [5599/5781] Mean julian date; starting time
of the first segment in the observing
sequence (JD-2550000)
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Note (1): More comprehensive and detailed description of these observations can
be found on the ASTRAL project webpage;
http://casa.colorado.edu/~ayres/ASTRAL/
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 0.1nm lambda [1196/2858] Laboratory wavelength,
vacuum, Angstroms (G1)
10- 19 A10 --- Line Atomic and molecular line (G1)
21- 28 F8.2 [-] loggf [-8.2/0.8]? log, statistical
weight*oscillator strength (G1)
31- 36 I6 cm-1 Eup [42533/107721] Energy, upper (G1)
38- 42 F5.1 km/s RV-gcru [-17.8/13.2]? Radial velocity,
γCru, relative to the stellar RV
of 20.6km/s
44- 45 I2 km/s FWHM-gcru [9/99]? Full width at half maximum,
γCru
47- 52 F6.1 10-15mW/m2 LFint-gcru [1.7/4064]? Integrated line flux observed
at Earth, γCru, 10-15erg/s/cm2
54- 59 F6.1 mW/m2 LFs-gcru [0.7/1508]? Integrated line flux at the
surface of γCru
61- 65 F5.1 km/s RV-aori [-16.5/17.6]? Radial velocity, αOri
relative to the stellar RV of 20.6km/s
67- 68 I2 km/s FWHM-aori [10/82]? Full width at half maximum,
α Ori
70- 76 F7.1 10-15mW/m2 LFint-aori [0.6/15085]? Integrated line flux
observed at Earth, α Ori,
10-15erg/s/cm2
78- 83 F6.1 mW/m2 LFs-aori [0.1/2048]? Integrated line flux at the
surface of α Ori
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 0.1nm lambda [1244/2870] Laboratory wavelength,
vacuum, Angstroms (G1)
11- 15 A5 --- Line Atomic and molecular line (G1)
17- 21 F5.2 [-] loggf [-8.17/0.54] log, statistical
weight*oscillator strength (G1)
23- 26 F4.1 --- tau-lte [-7.8/0.8] LTE opacity (τLTE)
29- 33 I5 cm-1 Elow [0/56371] Energy, lower (G1)
36- 41 I6 cm-1 Eup [35051/105654] Energy, upper (G1)
43- 47 F5.1 km/s RV-em [-25.9/14.7]? Radial velocity, emission
line, relative to the stellar RV of
20.6km/s
49- 53 F5.1 km/s RV-abs1 [-20.3/32.7]? Radial velocity, absorption
line 1, relative to the stellar RV of
20.6km/s
55- 59 F5.1 km/s RV-abs2 [-31.2/5.2]? Radial velocity, absorption
line 2, relative to the stellar RV of
20.6km/s
61- 62 I2 km/s FWHM-em [8/64]? emission line full width at half
maximum
64- 66 I3 km/s FWHM-abs1 [7/921]? absorption line 1 FWHM
68- 69 I2 km/s FWHM-abs2 [10/34]? absorption line 2 FWHM
71- 77 F7.1 10-15mW/m2 LFint [1/23452]? integrated emission line flux
observed at Earth, 10-15 erg/s/cm2
79- 84 F6.1 mW/m2 LFs [0.4/8767.5]? integrated emission line
flux observed at the stellar surface,
erg/s/cm2
86- 90 F5.1 0.1nm EW1 [0/150.4]? Equivalent width, absorption
line 1, in Å units
92- 95 F4.1 0.1nm EW2 [0/86]? Equivalent width, absorption
line 2, in Å units
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 0.1nm lambda [1245/2882] Laboratory wavelength, vacuum,
Å (G1)
11- 15 A5 --- Line Atomic and molecular line (G1)
17- 21 F5.2 [-] loggf [-8.2/0.6]? log, statistical
weightXoscillator strength (G1)
23- 26 F4.1 --- tau-lte [-9/0.8]? LTE opacity (τLTE)
29- 33 I5 cm-1 Elow [0/83136]? Energy, lower, cm-1 (G1)
36- 41 I6 cm-1 Eup [35051/127612]? Energy, upper, cm-1 (G1)
43- 47 F5.1 km/s RV-em [-31.8/36.1]? Radial velocity, emission
line, relative to the stellar RV of
20.6km/s
49- 53 F5.1 km/s RV-abs1 [-43.9/18.8]? Radial velocity, absorption
line 1, relative to the stellar RV of
20.6km/s
55- 59 F5.1 km/s RV-abs2 [-21.1/38.6]? Radial velocity, absorption
line 2, relative to the stellar RV of
20.6km/s
61- 63 I3 km/s FWHM-em [15/101]? emission line full width at
half maximum
65- 66 I2 km/s FWHM-abs1 [5/57]? absorption line 1 FWHM
68- 69 I2 km/s FWHM-abs2 [6/96]? absorption line 2 FWHM
71- 77 F7.1 10-15mW/m2 LFint [0.3/84247.2]? integrated emission line
flux observed at Earth, 10-15erg/s/cm2
79- 85 F7.1 mW/m2 LFs [0.1/11572.4]? integrated emission line
flux observed at the stellar surface,
erg/s/cm2
87- 91 F5.1 0.1nm EW1 [0/46.1]? Equivalent width, absorption
line 1, in Å units
93- 96 F4.1 0.1nm EW2 [0/21.4]? Equivalent width, absorption
line 2, in Å units
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Global notes:
Note (G1): Up-to-date laboratory atomic and molecular line data from the
literature, taken primarily from Kurucz (http://kurucz.harvard.edu/)
and NIST ASD (Version 5.6, http://www.nist.gov/pml/data/asd.cfm) line
databases.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie FIX [CDS] 13-Nov-2019