J/ApJ/766/9 GALEX observations of exoplanet host stars (Shkolnik, 2013)
An ultraviolet investigation of activity on exoplanet host stars.
Shkolnik E.L.
<Astrophys. J., 766, 9 (2013)>
=2013ApJ...766....9S 2013ApJ...766....9S
ADC_Keywords: Photometry, ultraviolet ; Planets ; Stars, double and multiple
Keywords: planetary systems; planet-star interactions; stars: activity;
stars: late-type
Abstract:
Using the far-UV (FUV) and near-UV (NUV) photometry from the NASA
Galaxy Evolution Explorer (GALEX), we searched for evidence of
increased stellar activity due to tidal and/or magnetic star-planet
interactions (SPI) in the 272 known FGK planetary hosts observed by
GALEX. With the increased sensitivity of GALEX, we are able probe
systems with lower activity levels and at larger distances than what
has been done to date with X-ray satellites. We compared samples of
stars with close-in planets (a<0.1AU) to those with far-out planets
(a>0.5AU) and looked for correlations of excess activity with other
system parameters. This statistical investigation found no clear
correlations with a, Mp, or Mp/a, in contrast to some X-ray and
CaII studies. However, there is tentative evidence (at a level of
1.8σ) that stars with radial-velocity-(RV)-detected close-in
planets are more FUV-active than stars with far-out planets, in
agreement with several published X-ray and Ca II results. The case is
strengthened to a level of significance to 2.3σ when
transit-detected close-in planets are included. This is most likely
because the RV-selected sample of stars is significantly less active
than the field population of comparable stars, while the
transit-selected sample is similarly active. Given the factor of 2-3
scatter in fractional FUV luminosity for a given stellar effective
temperature, it is necessary to conduct a time-resolved study of the
planet hosts in order to better characterize their UV variability and
generate a firmer statistical result.
Description:
The GALEX satellite was launched on 2003 April 28 and has imaged
approximately three-fourths of the sky simultaneously in two UV bands:
near-UV (NUV) 1750-2750Å and far-UV (FUV) 1350-1750Å, with
angular resolutions of 5" and 6.5", respectively, across a 1.25°
field of view. In addition to a medium and a deep imaging survey (MIS,
DIS), covering 1000 and 100 square degrees, respectively, the GALEX
mission has produced an All-sky Imaging Survey (AIS) in both UV bands
which is archived at the Multi-mission Archive at the Space Telescope
Science Institute (MAST).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 140 271 Planet and stellar data for GALEX detected stars
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See also:
II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
V/130 : Geneva-Copenhagen Survey of Solar neighbourhood III (Holmberg+, 2009)
J/ApJS/211/9 : Variability in UV line emission of F-M stars (Loyd+, 2014)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/A+A/540/A82 : CaIIHK emission in stars with planets (Krejcova+, 2012)
J/PASP/123/412 : Exoplanet Orbit Database (Wright+, 2011)
J/A+A/533/A90 : Radial velocity curves of HD 132563 (Desidera+, 2011)
J/A+A/517/L1 : Radial velocities of WASP-8b planet (Queloz+, 2010)
J/AJ/139/1338 : UV-selected stars in Tau and Upper Sco (Findeisen+, 2010)
J/MNRAS/389/869 : Multiplicity among bright stellar systems (Eggleton+, 2008)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/A+A/480/L33 : Radial velocities of HD 4113 and HD 156846 (Tamuz+, 2008)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/A+A/450/735 : Effective temperatures and radii of stars (Masana+, 2006)
J/ApJ/646/523 : Exoplanet systems with stellar companions (Raghavan+, 2006)
http://mastweb.stsci.edu/gcasjobs/ : GALEX archive Casjobs
http://galex.stsci.edu/galexview/ : GALEX MAST home page
http://www.exoplanets.org/ : Exoplanet Orbit database
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Star Star identifier; ordered by RA
15 A1 --- Pl [b-e] Planet identifier
17- 21 A5 --- Meth Discovery method (RV or "Tran.")
23- 27 F5.3 AU a [0.01/6.8] Semimajor axis (1)
29- 33 F5.2 Mjup Mp [0/26.4]? Mass of planet (1)
35- 38 I4 K Teff [4545/6600] Effective temperature (1)
40- 42 A3 --- Srv GALEX survey (AIS, GII, MIS or NGS; see II/312)
44 A1 --- l_FFUV [<] Limit flag on FFUV
45- 51 F7.2 uJy FFUV [1/1018]? GALEX FUV band (1350-1750Å) flux
density
53 A1 --- f_FFUV [s] Indicates FFUV is saturated (2)
55- 59 F5.2 uJy e_FFUV [0.1/28]? Uncertainty in FFUV
61- 67 F7.2 uJy FNUV ? GALEX NUV band (1750-2750Å) flux density
69 A1 --- f_FNUV [s] Indicates FNUV is saturated (2)
71- 75 F5.2 uJy e_FNUV ? Uncertainty in FNUV
77 A1 --- l_logLF Limit flag on logLF
78- 84 F7.3 [-] logLF [-10.1/-4.5]? Log of FUV to bolometric
luminosities (3)
86 A1 --- f_logLF [i] Indicates logLF is incomplete (3)
88- 92 F5.3 [-] e_logLF ? Uncertainty in logLF
94- 99 F6.3 [-] logLN [-7.5/-2.9]? Log of NUV to bolometric
luminosities (3)
101 A1 --- f_logLN [i] Indicates logLN is incomplete (3)
103-107 F5.3 [-] e_logLN ? Uncertainty in logLN
109-140 A32 --- Note Additional notes (4)
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Note (1): Data are listed only for the inner most planet of the multi-planet
systems. Masses are minimum masses for non-transiting planets. Planet
and stellar parameters come from the Exoplanet Data Explorer
(Wright et al. 2011, J/PASP/123/412).
Note (2): Saturated using the published counts-per-second limits per detector
in Morrissey et al. (2007ApJS..173..682M 2007ApJS..173..682M). These are 34cps and 108cps
for the FUV and NUV detectors, respectively.
Note (3): Bolometric corrections, BCK were calculated using
Equations 17 and 18 of Masana et al. (2006, J/A+A/450/735). For those
stars lacking literature values needed calculate BCK, the fractional
luminosities are left "incomplete".
Note (4):
* "Bad phot." refers to a >20% difference in flux calculated using
the auto and aper_7 apertures in the GALEX pipeline.
* "NUV artifact" refers to flags>2 returned the the GALEX pipeline
and should be used with caution. Binary blend are reported for those
stars with relatively bright companions within 30". Note that stars
with any of these flags were not used in the analyses presented in
this paper.
* The references for the close binaries are:
[1] = Raghavan et al. 2006, J/ApJ/646/523
[2] = Eggleton & Tokovinin, 2008, J/MNRAS/389/869,
[3] = Patience et al. 2002ApJ...581..654P 2002ApJ...581..654P,
[4] = Desidera et al. 2011, J/A+A/533/A90
[5] = Tamuz et al. 2008, J/A+A/480/L33
[6] = Mugrauer & Neuhauser, 2009A&A...494..373M 2009A&A...494..373M,
[7] = Queloz et al. 2010, J/A+A/517/L1.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Nov-2014