J/MNRAS/532/2875 Extreme velocity stars in the Galaxy (Nelson+, 2024)
A detailed chemical study of the extreme velocity stars in the Galaxy.
Nelson T., Hawkins K., Reggiani H., Garza D., Wyse R.F.G., Woody T.
<Mon. Not. R. Astron. Soc. 532, 2875-2891 (2024)>
=2024MNRAS.532.2875N 2024MNRAS.532.2875N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Abundances
Keywords: stars: abundances - stars: kinematics and dynamics - stars: late-type
Abstract:
Two decades on, the study of hypervelocity stars is still in its
infancy. These stars can provide novel constraints on the total mass
of the Galaxy and its Dark Matter distribution. However how these
stars are accelerated to such high velocities is unclear. Various
proposed production mechanisms for these stars can be distinguished
using chemo-dynamic tagging. The advent of Gaia and other large
surveys have provided hundreds of candidate hyper velocity objects to
target for ground based high resolution follow-up observations. We
conduct high resolution spectroscopic follow-up observations of 16
candidate late-type hyper velocity stars using the Apache Point
Observatory and the McDonald Observatory. We derive atmospheric
parameters and chemical abundances for these stars. We measure up to
22 elements, including the following nucleosynthetic families: alpha
(Mg, Si, Ca, Ti), light/Odd-Z (Na, Al, V, Cu, Sc), Fe-peak (Fe, Cr,
Mn, Co, Ni, Zn), and Neutron Capture (Sr, Y, Zr, Ba, La, Nd, Eu). Our
kinematic analysis shows one candidate is unbound, two are marginally
bound, and the remainder are bound to the Galaxy. Finally, for the
three unbound or marginally bound stars, we perform orbit integration
to locate possible globular cluster or dwarf galaxy progenitors. We do
not find any likely candidate systems for these stars and conclude
that the unbound stars are likely from the the stellar halo, in
agreement with the chemical results. The remaining bound stars are all
chemically consistent with the stellar halo as well.
Description:
In the following tables we provide photometric data, kinematics,
stellar parameters, and detailed elemental abundances (including both
LTE and NLTE measurements where applicable) for 36 Na,Mg, Al, Si, Ca,
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Nd, and Eu
for 42 stars used in this study. These stars include the science
sample, the sample from KH 2018 re-analyzed with our pipeline, and
benchmark/calibration stars. Science stars from this study use an
alias of star, stars from the Hawkins sample use an alias of Hawkins,
and stars from calibration data use their SIMBAD name. We also list
the atomic data used (oscillator strengths), the excitation potential,
and the absolute abundance (after subtraction the solar abundance from
Grevesse et al., 2007, Space Sci. Rev., 130, 105).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 16 Observational data gathered for the science
program stars
table2.dat 232 16 Photometric data used for Isochrones fitting for
the science stars in the program
table3.dat 100 8506 *Atomic Data Used for the LoneStar abundance fits
table4.dat 1557 36 *Atmospheric parameters and abundances for stars
used in this study
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Note on table3.dat: Data is primarily from the Gaia ESO V linelist and includes
HFS for several species
Note on table4.dat: These values are derived from a combination of lonestar and
isochrones. The listed [X/H] values are after any NLTE corrections are
applied. For elements with such corrections, a separate LTE column is
provided to allow the reader to see the uncorrected data.
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 source id
21- 27 A7 --- Name Alias of star for the program
29- 31 A3 --- Obs Which observatory the data was gathered at
(McD is McDonald Observatory,
APO is Apache Point Observatory)
33- 40 F8.4 deg RAdeg Right ascension of star (ICRS) at Ep=2016.0
42- 49 F8.4 deg DEdeg Declination of star (ICRS) at Ep=2016.0
51- 55 I5 pc Dist Distance estimate from the Bailer-Jones et
al., (2021AJ....161..147B 2021AJ....161..147B, Cat. I/352)
catalog, using the photogeometric distances
57- 61 F5.2 mag Gmag Gaia G band magnitude from Gaia DR3
63- 68 F6.1 km/s RV Radial velocity measurement after barycentric
correction (determined using iSpec)
70- 72 F3.1 km/s RVcor Radial velocity measurement after barycentric
correction (determined using iSpec)
74- 75 I2 --- SNR Signal to noise ratio for the data
77-113 A37 --- Ref Source of the HVS candidate examined
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Name Alias of star for the program
9- 27 I19 --- GaiaDR3 Gaia DR3 source id
29- 34 F6.3 mag Gmag ? Measured Gaia G band photometry
36- 40 F5.2 mag Jmag ? Measured J band photometry
42- 45 F4.2 mag e_Jmag ? Error on the J band photometry
47- 51 F5.2 mag Hmag ? Measured H band photometry
53- 56 F4.2 mag e_Hmag ? Error on the H band photometry
58- 62 F5.2 mag Ksmag ? Measured Ks band photometry
64- 67 F4.2 mag e_Ksmag ? Error on the Ks band photometry
69- 73 F5.2 mag W1mag ? Measured W1 band photometry
75- 78 F4.2 mag e_W1mag ? Error on the W1 band photometry
80- 84 F5.2 mag W2mag ? Measured W2 band photometry
86- 89 F4.2 mag e_W2mag ? Error on the W2 band photometry
91- 96 F6.2 mag umagSM ? Measured SkyMapper u band photometry
98-103 F6.3 mag e_umagSM ? Error on the SkyMapper u band photometry
105-110 F6.2 mag vmagSM ? Measured SkyMapper v band photometry
112-116 F5.2 mag e_vmagSM ? Error on the SkyMapper v band photometry
118-124 F7.3 mag gmagSM ? Measured SkyMapper g band photometry
126-131 F6.3 mag e_gmagSM ? Error on the SkyMapper g band photometry
133-139 F7.3 mag rmagSM ? Measured SkyMapper r band photometry
141-146 F6.3 mag e_rmagSM ? Error on the SkyMapper r band photometry
148-154 F7.3 mag imagSM ? Measured SkyMapper i band photometry
156-161 F6.3 mag e_imagSM ? Error on the SkyMapper i band photometry
163-169 F7.3 mag zmagSM ? Measured SkyMapper z band photometry
171-176 F6.3 mag e_zmagSM ? Error on the SkyMapper z band photometry
178-184 F7.3 mag gmagPS1 ? Measured PANSTARRs g band photometry
186-191 F6.3 mag e_gmagPS1 ? Error on the PANSTARRs g band photometry
193-199 F7.3 mag ymagPS1 ? Measured PANSTARRs y band photometry
201-206 F6.3 mag e_ymagPS1 ? Error on the PANSTARRs y band photometry
208-213 F6.2 mag umag ? Measured SDSS u band photometry
215-219 F5.2 mag e_umag ? Error on the SDSS u band photometry
221-226 F6.2 mag zmag ? Measured SDSS z band photometry
228-232 F5.2 mag e_zmag ? Error on the SDSS z band photometry
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Alias of star for the program
11- 16 A6 --- Element Element and Ionization state
18- 25 F8.3 0.1nm lambda Wavelength of atomic transition
27- 32 F6.3 [-] loggf Oscillator strength f multiplied by
its statistical weight g
34- 72 A39 --- r_loggf Bibliographic reference for data from the
Gaia ESO line list master table
74- 79 F6.3 eV xi Excitation potential
81-100 F20.16 [-] logeps Absolute abundance after subtracting solar
abundances from Grevesse et al., 2007,
Space Sci. Rev., 130, 105
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Alias of star for the program
11- 19 A9 --- Program Program label (1)
21- 26 F6.1 K Teff ? Effective temperature
28- 32 F5.1 K e_Teff ? Effective temperature error
34- 37 F4.2 [cm/s2] logg ? Surface gravity measurement
provided by isochrones
39- 42 F4.2 [cm/s2] e_logg ? Error on the surface gravity measurement
from isochrones
44- 63 F20.17 [-] [Fe/H] ? [Fe/H] abundance measurement
65- 84 F20.18 [-] e_[Fe/H] ? Error on the [Fe/H] abundance
measurement
86- 105 F20.17 [-] [Fe/H]LTE ? LTE [Fe/H] abundance measurement
from LoneStar
107- 112 F6.4 km/s xi ? micro turbulence as measured by LoneStar
114- 134 F21.18 [-] [Na/H] ? [Na/H] abundance measurement
136- 156 F21.18 [-] e_[Na/H] ? Error on the [Na/H] abundance
measurement
158- 178 F21.18 [-] [Na/Fe] ? [Na/Fe] abundance measurement
from LoneStar
180- 199 F20.17 [-] [Mg/H] ? [Mg/H] abundance measurement
201- 221 F21.18 [-] e_[Mg/H] ? Error on the [Mg/H] abundance
measurement
223- 243 F21.18 [-] [Mg/Fe] ? [Mg/Fe] abundance measurement
from LoneStar
245- 263 F19.16 [-] [Mg/H]LTE ? LTE [Mg/H] abundance measurement
from LoneStar
265- 284 F20.17 [-] [Al/H] ? [Al/H] abundance measurement
286- 306 F21.18 [-] e_[Al/H] ? Error on the [Al/H] abundance
measurement
308- 327 F20.17 [-] [Al/Fe] ? [Al/Fe] abundance measurement
from LoneStar
329- 348 F20.17 [-] [Si/H] ? [Si/H] abundance measurement
350- 370 F21.18 [-] e_[Si/H] ? Error on the [Si/H] abundance
measurement
372- 392 F21.18 [-] [Si/Fe] ? [Si/Fe] abundance measurement
from LoneStar
394- 414 F21.18 [-] [Si/H]LTE ? LTE [Si/H] abundance measurement
from LoneStar
416- 435 F20.17 [-] [Ca/H] ? [Ca/H] abundance measurement
437- 456 F20.18 [-] e_[Ca/H] ? Error on the [Ca/H] abundance
measurement
458- 478 F21.18 [-] [Ca/Fe] ? [Ca/Fe] abundance measurement
from LoneStar
480- 499 F20.17 [-] [Ca/H]LTE ? LTE [Ca/H] abundance measurement
from LoneStar
501- 521 F21.18 [-] [Sc/H] ? [Sc/H] abundance measurement
523- 542 F20.18 [-] e_[Sc/H] ? Error on the [Sc/H] abundance
measurement
544- 562 F19.17 [-] [Sc/Fe] ? [Sc/Fe] abundance measurement
from LoneStar
564- 584 F21.18 [-] [Ti/H] ? [Ti/H] abundance measurement
586- 605 F20.18 [-] e_[Ti/H] ? Error on the [Ti/H] abundance
measurement
607- 625 F19.17 [-] [Ti/Fe] ? [Ti/Fe] abundance measurement
from LoneStar
627- 647 F21.18 [-] [Ti/H]LTE ? LTE [Ti/H] abundance measurement
from LoneStar
649- 668 F20.17 [-] [V/H] ? [V/H] abundance measurement
670- 690 F21.18 [-] e_[V/H] ? Error on the [V/H] abundance measurement
692- 712 F21.18 [-] [V/Fe] ? [V/Fe] abundance measurement
from LoneStar
714- 733 F20.17 [-] [Cr/H] ? [Cr/H] abundance measurement
735- 754 F20.18 [-] e_[Cr/H] ? Error on the [Cr/H] abundance
measurement
756- 777 F22.19 [-] [Cr/Fe] ? [Cr/Fe] abundance measurement
from LoneStar
779- 798 F20.17 [-] [Mn/H] ? [Mn/H] abundance measurement
800- 820 F21.18 [-] e_[Mn/H] ? Error on the [Mn/H] abundance
measurement
822- 843 F22.19 [-] [Mn/Fe] ? [Mn/Fe] abundance measurement
from LoneStar
845- 863 F19.16 [-] [Mn/H]LTE ? LTE [Mn/H] abundance measurement
from LoneStar
865- 885 F21.18 [-] [Co/H] ? [Co/H] abundance measurement
887- 907 F21.18 [-] e_[Co/H] ? Error on the [Co/H] abundance
measurement
909- 928 F20.17 [-] [Co/Fe] ? [Co/Fe] abundance measurement
from LoneStar
930- 949 F20.17 [-] [Co/H]LTE ? LTE [Co/H] abundance measurement
from LoneStar
951- 971 F21.18 [-] [Ni/H] ? [Ni/H] abundance measurement
973- 992 F20.18 [-] e_[Ni/H] ? Error on the [Ni/H] abundance
measurement
994-1014 F21.18 [-] [Ni/Fe] ? [Ni/Fe] abundance measurement
from LoneStar
1016-1034 F19.16 [-] [Cu/H] ? [Cu/H] abundance measurement
1036-1056 F21.18 [-] e_[Cu/H] ? Error on the [Cu/H] abundance
measurement
1058-1079 F22.19 [-] [Cu/Fe] ? [Cu/Fe] abundance measurement
from LoneStar
1081-1100 F20.17 [-] [Zn/H] ? [Zn/H] abundance measurement
1102-1122 F21.18 [-] e_[Zn/H] ? Error on the [Zn/H] abundance
measurement
1124-1146 E23.16 [-] [Zn/Fe] ? [Zn/Fe] abundance measurement
from LoneStar
1148-1166 F19.16 [-] [Sr/H] ? [Sr/H] abundance measurement
1168-1187 F20.17 [-] e_[Sr/H] ? Error on the [Sr/H] abundance
measurement
1189-1210 F22.19 [-] [Sr/Fe] ? [Sr/Fe] abundance measurement
from LoneStar
1212-1230 F19.16 [-] [Y/H] ? [Y/H] abundance measurement
1232-1251 F20.18 [-] e_[Y/H] ? Error on the [Y/H] abundance measurement
1253-1273 F21.18 [-] [Y/Fe] ? [Y/Fe] abundance measurement
from LoneStar
1275-1281 F7.4 [-] [Zr/H] ? [Zr/H] abundance measurement
1283-1303 F21.18 [-] e_[Zr/H] ? Error on the [Zr/H] abundance
measurement
1305-1325 F21.18 [-] [Zr/Fe] ? [Zr/Fe] abundance measurement
from LoneStar
1327-1333 F7.4 [-] [Ba/H] ? [Ba/H] abundance measurement
1335-1355 F21.18 [-] e_[Ba/H] ? Error on the [Ba/H] abundance
measurement
1357-1378 F22.19 [-] [Ba/Fe] ? [Ba/Fe] abundance measurement
from LoneStar
1380-1400 F21.18 [-] [La/H] ? [La/H] abundance measurement
1402-1421 F20.17 [-] e_[La/H] ? Error on the [La/H] abundance
measurement
1423-1443 F21.18 [-] [La/Fe] ? [La/Fe] abundance measurement
from LoneStar
1445-1464 F20.17 [-] [Nd/H] ? [Nd/H] abundance measurement
1466-1486 F21.18 [-] e_[Nd/H] ? Error on the [Nd/H] abundance
measurement
1488-1507 F20.17 [-] [Nd/Fe] ? [Nd/Fe] abundance measurement
from LoneStar
1509-1514 F6.3 [-] [Eu/H] ? [Eu/H] abundance measurement
1516-1536 F21.18 [-] e_[Eu/H] ? Error on the [Eu/H] abundance
measurement
1538-1557 F20.17 [-] [Eu/Fe] ? [Eu/Fe] abundance measurement
from LoneStar
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Note (1): Label for whether the star is as follows:
science = a science star
kh_star = a star from Hawkins et al. 2018MNRAS.481.1028H 2018MNRAS.481.1028H
std = a benchmark star (from either the Gaia benchmark stars or
Bensby et al., 2014A&A...562A..71B 2014A&A...562A..71B, Cat. J/A+A/562/A71)
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Acknowledgements:
Tyler Nelson, tyler.w.nelson(at)maine.edu
(End) Patricia Vannier [CDS] 05-Jul-2024