J/ApJ/756/L33 Radial velocities of 2 hot Jupiters in Praesepe (Quinn+, 2012)
Two "b"s in the Beehive: the discovery of the first hot Jupiters in an
open cluster.
Quinn S.N., White R.J., Latham D.W., Buchhave L.A., Cantrell J.R.,
Dahm S.E., Furesz G., Szentgyorgyi A.H., Geary J.C., Torres G., Bieryla A.,
Berlind P., Calkins M.C., Esquerdo G.A., Stefanik R.P.
<Astrophys. J., 756, L33 (2012)>
=2012ApJ...756L..33Q 2012ApJ...756L..33Q
ADC_Keywords: Radial velocities ; Clusters, open ; Stars, double and multiple ;
Planets
Keywords: open clusters and associations: individual (Praesepe, M44, NGC 2632,
Beehive); planetary systems; stars: individual (BD+20 2184,
2MASS J08421149+1916373)
Abstract:
We report the discovery of two giant planets orbiting stars in
Praesepe (also known as the Beehive Cluster). These are the first
known hot Jupiters in an open cluster and the only planets known to
orbit Sun-like, main-sequence stars in a cluster. The planets are
detected from Doppler-shifted radial velocities; line bisector spans
and activity indices show no correlation with orbital phase,
confirming the variations are caused by planetary companions. Pr0201b
orbits a V=10.52 late F dwarf with a period of 4.4264±0.0070 days
and has a minimum mass of 0.540±0.039MJup, and Pr0211b orbits a
V=12.06 late G dwarf with a period of 2.1451±0.0012 days and has a
minimum mass of 1.844±0.064MJup. The detection of two planets
among 53 single members surveyed establishes a lower limit of
3.8+5.0-2.4% on the hot Jupiter frequency in this metal-rich open
cluster. Given the precisely known age of the cluster, this discovery
also demonstrates that, in at least two cases, giant planet migration
occurred within 600Myr after formation. As we endeavor to learn more
about the frequency and formation history of planets, environments
with well-determined properties--such as open clusters like
Praesepe--may provide essential clues to this end.
Description:
Cluster members were selected from the membership list assembled by
Kraus & Hillenbrand (2007, Cat. J/AJ/134/2340), excluding stars with
known spectroscopic or visual companions.
We used the Tillinghast Reflector Echelle Spectrograph (TRES) mounted
on the 1.5m Tillinghast Reflector at the Fred L. Whipple Observatory
on Mt. Hopkins, AZ to obtain high resolution spectra of Praesepe
stars, between UT 2012 January 6 and 2012 April 16. TRES is a
temperature-controlled, fiber-fed instrument with a resolving power of
R∼44000 and a wavelength coverage of ∼3850-9100Å, spanning 51
echelle orders.
Accounting for internal, instrumental, and stellar noise, we
constructed a χ2 fit of each star's RVs assuming a constant
velocity, and then calculated P(χ2), the probability that the
observed χ2 value would arise from a star of constant RV. Pr0201
(BD+20 2184) and Pr0211 (2MASS J08421149+1916373) stood out, with
P(χ2)<0.001. We obtained additional spectra of these stars, and
in both cases a Lomb-Scargle periodogram revealed significant
periodicity. Their radial velocities are presented in Table 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 53 Target list and observation summary
table2.dat 29 51 Relative radial velocities of planet hosts
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See also:
J/A+A/561/A93 : On the metallicity of open clusters. II. (Heiter+, 2014)
J/A+A/556/A150 : SWEETCat I. Stellar parameters for host stars (Santos+, 2013)
J/A+A/552/A119 : Planet-star and moon-planet interaction (Saur+, 2013)
J/MNRAS/428/2321 : Abundances of open cluster stars (Mitschang+, 2013)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/ApJ/750/98 : 24um obs. of AFGKM stars of 3 clusters (Urban+, 2012)
J/MNRAS/413/2218 : Stellar rotation in Hyades and Praesepe (Delorme+, 2011)
J/ApJ/720/1118 : i-band photometry of HAT-P-16 (Buchhave+, 2010)
J/ApJ/697/1578 : A debris disk study of Praesepe (Gaspar+, 2009)
J/A+A/498/949 : Velocities of F-K dwarfs in open clusters (Mermilliod+, 2009)
J/A+A/489/403 : Line abundances for solar stars (Pace+, 2008)
J/AJ/135/907 : Variables in Praesepe identified with KELT (Pepper+, 2008)
J/AJ/134/2340 : Praesepe & Coma Berenices clusters membership (Kraus+, 2007)
J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)
J/AJ/124/1570 : JHKs photometry in Praesepe (Adams+, 2002)
J/A+A/375/989 : JHK photometry of Praesepe low-mass stars (Bouvier+, 2001)
J/AJ/109/1379 : Praesepe + M 67 spectral standards (Allen+ 1995)
J/A+AS/109/29 : Very low mass stars in Praesepe (Hambly+, 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Object Name (<[QWL2012] PrNNNN> in Simbad)
8- 9 I2 h RAh [8] Hour of Right Ascension (J2000)
11- 12 I2 min RAm [34/50] Minute of Right Ascension (J2000)
14- 17 F4.1 s RAs Second of Right Ascension (J2000)
19 A1 --- DE- [+] Declination sign (J2000)
21- 22 I2 deg DEd [18/21] Degree of Declination (J2000)
24- 25 I2 arcmin DEm Arcminute of Declination (J2000)
27- 30 F4.1 arcsec DEs Arcsecond of Declination (J2000)
32- 36 F5.2 mag Vmag [9.6/12.3] Apparent V magnitude
38- 39 I2 --- Nv [5/33] Number of radial velocities
41- 45 F5.1 m/s rms [9.3/228] RMS of the radial velocities
47- 52 F6.4 d Per [2.1/4.5]? Period (from table 3)
54- 59 F6.4 d e_Per [0.001/0.007]? Per uncertainty (from table 3)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Object Name (PR0201 or Pr0211)
8- 17 F10.6 d BJD Barycentric Julian Date; BJD-2455900
19- 24 F6.1 m/s RV [-193/504.4] Relative radial velocity
26- 29 F4.1 m/s e_RV [12/50.5] RV uncertainty (1)
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Note (1): The errors listed here are internal error estimates, but in the
orbital solutions we include an assumed stellar jitter of 13m/s and
an instrumental floor error of 9m/s, added in quadrature with the
internal errors.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 19-May-2014