J/MNRAS/441/3543 Possible planets around A stars (Balona, 2014)
Possible planets around A stars.
Balona L.A.
<Mon. Not. R. Astron. Soc., 441, 3543-3549 (2014)>
=2014MNRAS.441.3543B 2014MNRAS.441.3543B
ADC_Keywords: Stars, A-type ; Stars, double and multiple ; Planets
Keywords: stars: activity - stars: oscillations - planetary systems -
stars: rotation
Abstract:
Kepler photometry of A stars shows that a considerable fraction
(about 19 per cent) have a peculiar feature in the periodogram. This
feature consists of a broad peak, thought to be due to differential
rotation in a spotted star, and a sharp peak at slightly higher
frequency. The pattern clearly involves some widespread stellar
property and the sharp peak implies a strictly coherent periodicity.
We investigate the possibility that the periodicity is due to
rotation, pulsation or an orbital effect. We argue that neither
rotation nor pulsation can provide a suitable, testable, explanation.
We suggest that the sharp feature could be due to a planet in
synchronous orbit around the rapidly rotating, spotted A star, not
necessarily in transit. Spectroscopic observations of sufficient
precision are required to falsify this hypothesis.
Description:
The Kepler Input Catalogue (KIC; Brown et al., 2011, Cat. V/133)
provides estimates of effective temperature, surface gravity and radii
for practically all stars in the Kepler field from ground-based
multicolour photometry. The light curves for all Kepler A stars, i.e.
stars with effective temperatures, Teff, in the range 7500<Teff<10000K
are available in the Mikulski Archive for Space Telescopes (MAST,
http://archive.stsci.edu/).
The photometry is available as simple aperture photometry (SAP) in
which instrumental drifts and jumps are present and 'pre-search data
conditioning' (PDC) flux in which the SAP photometry is corrected
(Stumpe et al., 2012PASP..124..985S 2012PASP..124..985S). We decided to use the PDC
photometry, even though instrumental effects are clearly present in
some stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 166 List of A stars in which the characteristic
frequency pattern has been detected
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC KIC identification number
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 17 I2 s RAs Right ascension (J2000)
19 A1 --- DE- Declination sign (J2000)
20- 21 I2 deg DEd Declination (J2000)
23- 24 I2 arcmin DEm Declination (J2000)
26- 27 I2 arcsec DEs Declination (J2000)
29- 34 F6.3 mag kepmag [7.5/51.3] Kepler magnitude
36- 41 F6.4 [K] logTe [3.8/4.1] Effective temperature derived from KIC
43- 49 F7.4 [Lsun] logL [0.8/2.4]?=-1 Luminosity derived from KIC
51- 55 F5.3 d-1 nurot [0.1/3] Presumed rotational frequency peak
57- 61 F5.3 mmag Amp [0/4] Amplitude of variation
63- 67 F5.1 --- S/N [4.5/114] Signal-to-noise ratio (1)
69 A1 --- Note [D] D indicates a δ Scuti star
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Note (1): the ratio of the amplitude to the mean local background noise
in the periodogram.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 12-Feb-2015