J/MNRAS/466/546 Parameters for the 172 λ Boo stars (Murphy+, 2017)
Gaia's view of the λ Boo star puzzle.
Murphy S.J., Paunzen E.
<Mon. Not. R. Astron. Soc., 466, 546-555 (2017)>
=2017MNRAS.466..546M 2017MNRAS.466..546M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, peculiar ; Stars, early-type ; Photometry ;
Effective temperatures
Keywords: accretion, accretion discs - asteroseismology -
stars: chemically peculiar - circumstellar matter - stars: distances -
ISM: clouds
Abstract:
The evolutionary status of the chemically peculiar class of λ
Boo stars has been intensely debated. It is now agreed that the
λ Boo phenomenon affects A stars of all ages, from star
formation to the terminal age main sequence, but the cause of the
chemical peculiarity is still a puzzle. We revisit the debate of their
ages and temperatures in order to shed light on the phenomenon, using
the new parallaxes in Gaia Data Release 1 with existing Hipparcos
parallaxes and multicolour photometry. We find that no single
formation mechanism is able to explain all the observations, and
suggest that there are multiple channels producing λ Boo
spectra. The relative importance of these channels varies with age,
temperature and environment.
Description:
The starting point of our target selection was the catalogue of bona
fide λ Boo stars by Murphy et al. (2015, Cat.
J/other/PASA/32.36). From this sample, we made two selections. First,
we selected objects for which parallaxes with an error smaller than 25
per cent in the Hipparcos catalogue (van Leeuwen 2007, Cat. I/311)
and/or Gaia DR1 (Gaia Collaboration et al., 2016, Cat. I/337) are
available. Most of the parallaxes are much smaller than 25 per cent,
as we discuss in Section 2.2. Secondly, we included only those stars
with available Johnson UBV, Stroemgren-Crawford uvbyβ and Geneva
7-colour photometry, taken from Paunzen (2015, Cat. J/A+A/580/A23) and
the General Catalogue of Photometric Data (GCPD1). Where possible,
averaged and weighted mean values were used throughout. The final
sample consists of 172 stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 97 172 Parameters for the 172 λ Boo stars and
candidates considered in this work,
with Hipparcos or Gaia parallaxes
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See also:
J/other/PASA/32.36 : lambda Boo star membership evaluations (Murphy+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number
8- 22 A15 --- Name HIP/TYC name
24 I1 --- Memb Membership code (1)
26- 31 F6.3 mag Vmag V magnitude
33- 37 F5.3 mag AV Absorption in V band
39- 43 F5.2 mag BC Bolometric correction
45- 49 I5 K Teff Effective temperature
51- 53 I3 K e_Teff rms uncertainty on Teff
55- 59 F5.2 mag VMAGH ?=- Hipparcos absolute V magnitude
61- 64 F4.2 mag e_VMAGH ? rms uncertainty on VMAGH
66- 70 F5.2 mag VMAGG ?=- Gaia absolute V magnitude
72- 75 F4.2 mag e_VMAGG ? rms uncertainty on VMAGG
77- 80 F4.2 [Lsun] logL Luminosity
82- 85 F4.2 [Lsun] e_logL rms uncertainty on logL
87- 97 A11 --- var? Variability type from sources described
in Section 3.1
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Note (1): Membership probability in the λ Boo class (from Murphy et al.
2015, Cat. J/other/PASA/32.36) is indicated with integers between 1 and 4,
with 1 being certain members and 4 being non-members.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Aug-2019