J/ApJ/818/106 MILO. I. HD 7449 radial velocities (Rodigas+, 2016)
MagAO Imaging of Long-period Objects (MILO).
I. A benchmark M dwarf companion exciting a massive planet around the Sun-like
star HD 7449.
Rodigas T.J., Arriagada P., Faherty J., Anglada-Escude G., Kaib N.,
Butler R.P., Shectman S., Weinberger A., Males J.R., Morzinski K.M.,
Close L.M., Hinz P.M., Crane J.D., Thompson I., Teske J., Diaz M.,
Minniti D., Lopez-Morales M., Adams F.C., Boss A.P.
<Astrophys. J., 818, 106 (2016)>
=2016ApJ...818..106R 2016ApJ...818..106R (SIMBAD/NED BibCode)
ADC_Keywords: Radial velocities ; Stars, double and multiple
Keywords: binaries: general; instrumentation: adaptive optics;
planetary systems; stars: individual: HD 7449;
techniques: high angular resolution; techniques: radial velocities
Abstract:
We present high-contrast Magellan adaptive optics images of HD 7449, a
Sun-like star with one planet and a long-term radial velocity (RV)
trend. We unambiguously detect the source of the long-term trend from
0.6-2.15µm at a separation of ∼0.54". We use the object's colors
and spectral energy distribution to show that it is most likely an
M4-M5 dwarf (mass ∼0.1-0.2M☉) at the same distance as the
primary and is therefore likely bound. We also present new RVs
measured with the Magellan/MIKE and Planet Finder Spectrograph (PFS)
spectrometers and compile these with archival data from CORALIE and
HARPS. We use a new Markov chain Monte Carlo procedure to constrain
both the mass (>0.17M☉ at 99% confidence) and semimajor axis
(∼18 AU) of the M dwarf companion (HD 7449B). We also refine the
parameters of the known massive planet (HD 7449Ab), finding that its
minimum mass is 1.09-0.19+0.52MJ, its semimajor axis is
2.33-0.02+0.01AU, and its eccentricity is 0.8-0.06+0.08. We
use N-body simulations to constrain the eccentricity of HD 7449B to
≲0.5. The M dwarf may be inducing Kozai oscillations on the planet,
explaining its high eccentricity. If this is the case and its orbit
was initially circular, the mass of the planet would need to be
≲1.5MJ. This demonstrates that strong constraints on known planets
can be made using direct observations of otherwise undetectable
long-period companions.
Description:
We observed HD 7449 using the Magellan Clay Telescope at the Las
Campanas Observatory in Chile on the nights of UT 2014 November 5 and
22. We observed the star with VisAO at Ys (0.99um) and with Clio-2 at
H (1.65um) and Ks (2.15um) on the first night and with VisAO at r'
(0.63um), i' (0.77um), z' (0.91um), and with Clio-2 at J (1.1um) on
the second night.
RV data on HD 7449 were first acquired as part of the Magellan Planet
Search Program, which originally made use of the MIKE echelle
spectrometer (R∼70000 in the blue and ∼50000 in the red; wavelength
coverage ranges from 3900 to 6200Å) on the Magellan Clay telescope
until 2009 September.
HD 7449 was subsequently observed using the Carnegie Magellan/PFS
(3880-6680Å with R∼80000 in the iodine region).
We also included in our analysis RVs measured with HARPS and CORALIE.
These RVs were originally reported in Dumusque et al. (2011,
J/A+A/535/A55). HARPS data on HD 7449 has been supplemented by the ESO
archive. See section 2.2 for further explanations.
Objects:
------------------------------------------------------
RA (ICRS) DE Designation(s)
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01 14 29.32 -05 02 50.6 HD 7449 = TYC 4683-883-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 28 201 Radial velocities for HD 7449
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See also:
J/A+A/585/A5 : Exoplanet hosts/field stars age consistency (Bonfanti+, 2016)
J/A+A/576/A69 : Li abundances in F stars (Delgado+, 2015)
J/A+A/575/A18 : Revising the ages of planet-hosting stars (Bonfanti+, 2015)
J/ApJ/799/163 : Chandra observations of solar analogs (Miller+, 2015)
J/MNRAS/445/2223 : Mass estimation for FGK stars (Pinheiro+, 2014)
J/MNRAS/443/L89 : Kapteyn's star spectrosc. measurements (Anglada-Escude+ 2014)
J/AJ/147/86 : From binaries to multiples. I. FG-67 sample (Tokovinin, 2014)
J/A+A/556/A150 : SWEETCat I. Stellar parameters for host stars (Santos+, 2013)
J/A+A/555/A150 : Physical param. of cool solar-type stars (Tsantaki+, 2013)
J/A+A/552/A119 : Planet-star and moon-planet interaction (Saur+, 2013)
J/A+A/552/A64 : Gaia-RVS standards (Soubiran+, 2013)
J/A+A/552/A6 : F-G MS stars abundances (Gonzalez Hernandez+, 2013)
J/A+A/551/A112 : Metallicity-giant planet correlation (Mortier+, 2013)
J/ApJ/766/9 : GALEX observations of exoplanet host stars (Shkolnik, 2013)
J/ApJS/200/15 : HARPS-TERRA project. I. (Anglada-Escude+, 2012)
J/ApJ/752/56 : BDKP III. Parallaxes for 70 ultracool dwarfs (Faherty+, 2012)
J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)
J/AJ/142/176 : Exoplanet host stars. II. Interferometry (Mason+, 2011)
J/A+A/535/A55 : 4 stars with long-period planets (Dumusque+, 2011)
J/ApJ/709/168 : Eccentric orbits in exoplanets (Anglada-Escude+, 2010)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/A+A/487/373 : Spectroscopic param. of 451 HARPS-GTO stars (Sousa+, 2008)
J/AJ/124/1144 : Orbits of single-lined spectroscopic binaries (Latham, 2002)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d JD Julian Date of the observation
15- 20 F6.2 m/s RVel [-34/108] Radial velocity
22- 26 F5.2 m/s e_RVel [0.5/10] Uncertainty in RVel
28 I1 --- Inst Instrument code (1)
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Note (1): Instrument as follows:
1 = CORALIE (Dumusque et al. 2011, J/A+A/535/A55);
2 = HARPS;
3 = Magellan/MIKE;
4 = Magellan/PFS.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 29-Apr-2016