J/ApJ/711/138 Spectral analysis of HIP 60350 and 18 Peg (Irrgang+, 2010)
The nature of the hyper-runaway candidate HIP 60350.
Irrgang A., Przybilla N., Heber U., Nieva M. F., Schuh S.
<Astrophys. J., 711, 138-143 (2010)>
=2010ApJ...711..138I 2010ApJ...711..138I
ADC_Keywords: Abundances ; Stars, B-type ; Spectroscopy
Keywords: stars: abundances - stars: atmospheres - stars: distances -
stars: early-type - stars: individual (HIP 60350, 18 Peg) -
stars: kinematics and dynamics
Abstract:
Young, massive stars in the Galactic halo are widely supposed to be
the result of an ejection event from the Galactic disk forcing some
stars to leave their place of birth as so-called runaway stars. Here,
we present a detailed spectroscopic and kinematic analysis of the
runaway B star HIP 60350 to determine which runaway scenario -a
supernova explosion disrupting a binary system or dynamical
interaction in star clusters- may be responsible for HIP 60350's
peculiar orbit. Based on a non-local thermodynamic equilibrium
approach, a high-resolution optical echelle spectrum was examined to
revise spectroscopic quantities and for the first time to perform a
differential chemical abundance analysis with respect to the B-type
star 18 Peg. The results together with proper motions from the
Hipparcos Catalog further allowed the three-dimensional kinematics of
the star to be studied numerically. The abundances derived for
HIP 60350 are consistent with a slightly supersolar metallicity
agreeing with the kinematically predicted place of birth ∼6kpc away
from the Galactic center. However, they do not exclude the possibility
of an α-enhanced abundance pattern expected in the case of the
supernova scenario. Its outstanding high Galactic rest-frame velocity
of 530±35km/s is a consequence of ejection in the direction of
Galactic rotation and slightly exceeds the local Galactic escape
velocity in a standard Galactic potential. Hence, HIP 60350 may be
unbound to the Galaxy.
Description:
HIP 60350 was observed in 2008 December with the high-resolution
echelle spectrograph of the 9.2m Hobby-Eberly Telescope (HET) at the
McDonald Observatory in wavelength range [3900Å,7870Å]. Three
intermediate-resolution spectra taken in 2009 May and July with the
3.5m telescope at Calar Alto, Spain, enlarging the spectral coverage
down to 3500Å.
We also carried out an abundance analysis of the normal Population I
B-type star 18 Peg. We used the fibre optics Cassegrain echelle
spectrograph (FOCES) on the 2.2m telescope at Calar Alto, Spain, to
obtain a high-resolution, high-S/N spectrum (S/N∼400 in the blue) of
18 Peg.
Objects:
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RA (2000) DE Designation(s)
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12 22 29.61 +40 49 35.6 HIP 60350 = TYC 3018-248-1
22 00 07.93 +06 43 02.8 * 18 Peg = TYC 564-1847-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 68 167 Spectral line analysis of HIP 60350 and 18 Peg
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See also:
V/136 : Teff and metallicities for Tycho-2 stars (Ammons+, 2006)
J/A+A/539/A143 : Nearby B-stars stellar parameters and abundances (Nieva+,
2012)
J/MNRAS/410/190 : Young runaway stars within 3kpc (Tetzlaff+, 2011)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ion Ion species
7- 10 F4.2 [-] ? Averaged HIP 60350 abundance; log(X/H)+12
12- 15 F4.2 [-] e_ ? Uncertainty in
17- 20 F4.2 [-] <Peg> ? Averaged 18 Peg abundance; log(X/H)+12
22- 25 F4.2 [-] e_<Peg> ? Uncertainty in <Peg>
27- 33 F7.2 0.1nm lambda Wavelength; Angstroms
35- 39 F5.2 eV ExPot Excitation potential
41- 46 F6.3 [-] log(gf) Log of oscillator strength
48- 49 A2 --- Acc Accuracy indicator (1)
51- 58 A8 --- Ref Reference(s) (2)
60- 63 F4.2 [-] HIP ? HIP 60350 abundance from the line; log(X/H)+12
65- 68 F4.2 [-] Peg The 18 Peg abundance from the line; log(X/H)+12
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Note (1): Uncertainties are coded as:
A = 3%;
B = 10%;
C = 25%;
D = 50%;
E = larger than 50%;
X = unknown.
Note (2): References as follows:
BB89 = Becker & Butler 1989A&A...209..244B 1989A&A...209..244B;
BMZ = Butler, Mendoza, & Zeippen 1993JPhB...26.4409B 1993JPhB...26.4409B;
FFT = Froese Fischer & Tachiev 2004ADNDT..87....1F 2004ADNDT..87....1F;
FFTI = Froese Fischer, Tachiev, & Irimia 2006ADNDT..92..607F 2006ADNDT..92..607F;
FMW = Fuhr, Martin, & Wiese 1988atps.book.....M 1988atps.book.....M;
FW = Fuhr, J. R. & Wiese, W. L. 1998, CRC Handbook of Chemistry and Physics,
79th ed., ed. D. R. Lide (Boca Raton, FL: CRC Press);
KB = Kurucz & Bell 1995all..book.....K 1995all..book.....K;
MAR = Mar et al. 2000A&AS..144..509M 2000A&AS..144..509M;
MELZ = Mendoza et al. 1995JPhB...28.3485M 1995JPhB...28.3485M;
MERLR = Matheron et al. 2001JQSRT..69..535M 2001JQSRT..69..535M;
N02 = Nahar 2002ADNDT..80..205N 2002ADNDT..80..205N;
N86 = Nussbaumer 1986A&A...155..205N 1986A&A...155..205N;
WFD = Wiese, Fuhr, & Deters 1996atpc.book.....W 1996atpc.book.....W;
WSM = Wiese, Smith, & Miles, 1969atp..book.....W 1969atp..book.....W.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 30-Mar-2012