J/ApJ/759/L41 New radial velocities of HD 97658 (Dragomir+, 2012)
Non-detection of previously reported transits of HD 97658b with MOST photometry.
Dragomir D., Matthews J.M., Howard A.W., Antoci V., Henry G.W.,
Guenther D.B., Johnson J.A., Kuschnig R., Marcy G.W., Moffat A.F.J.,
Rowe J.F., Rucinski S.M., Sasselov D., Weiss W.W.
<Astrophys. J., 759, L41 (2012)>
=2012ApJ...759L..41D 2012ApJ...759L..41D
ADC_Keywords: Radial velocities ; Stars, double and multiple
Keywords: planetary systems; stars: individual: HD 97658;
techniques: photometric
Abstract:
The radial velocity-discovered exoplanet HD 97658b was recently
announced to transit, with a derived planetary radius of
2.93±0.28R⊕. As a transiting super-Earth orbiting a bright
star, this planet would make an attractive candidate for additional
observations, including studies of its atmospheric properties. We
present and analyze follow-up photometric observations of the HD 97658
system acquired with the Microvariability and Oscillations of STars
space telescope. Our results show no transit with the depth and
ephemeris reported in the announcement paper. For the same ephemeris,
we rule out transits for a planet with radius larger than
2.09R⊕, corresponding to the reported 3σ lower limit. We
also report new radial velocity measurements which continue to support
the existence of an exoplanet with a period of 9.5 days, and obtain
improved orbital parameters.
Description:
HD 97658 was observed, with MOST (Microvariability and Oscillations of
STars) space telescope, contiguously in Direct Imaging mode on 2012
February 25 for 11.8hr and again on 2012 March 5 and 6 for 22.8hr.
Since the publication of Howard et al. (2011ApJ...730...10H 2011ApJ...730...10H), we have
measured the RV of HD 97658 for nearly two additional observing
seasons (2010-2012) using Keck-HIRES. The full set of 169 RVs and SHK
measurements of the CaII H & K lines (Isaacson & Fischer 2010,
Cat. J/ApJ/725/875) from 2005 to 2012 are listed in Table 1. The SHK
measurements (indicators of stellar activity) are not correlated with
the RVs, consistent with a planetary origin for the RV variation.
Between late 2010 and early 2012, 73 measurements were recorded after
the submission of Howard et al. The RV measurements in common differ
slightly here because of modest re-weighting of spectral segments in
the Doppler analysis.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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11 14 33.16 +25 42 37.4 HD 97658 = TYC 1981-1168-1 (P=9.5)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 169 Radial velocities and SHK values for HD 97658
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See also:
J/A+A/552/A119 : Planet-star and moon-planet interaction (Saur+, 2013)
J/A+A/551/L8 : Chromospheric activity of field stars (Pace, 2013)
J/A+A/546/A61 : Radial velocities for XHIP catalogue (de Bruijne+, 2012)
J/A+A/537/A147 : Optimizing exoplanet transit searches (Herrero+, 2012)
J/PASP/123/412 : Exoplanet Orbit Database (Wright+, 2011)
J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)
J/A+A/524/A10 : Radial Velocity standard stars (Crifo+, 2010)
J/A+A/521/A12 : Radial velocities of nearby late-type stars (Maldonado+, 2010)
J/A+A/520/A79 : Nearby FGK stars chromosph. activity (Martinez-Arnaiz+, 2010)
J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)
J/ApJS/141/503 : Radial Velocities for 889 late-type stars (Nidever+, 2002)
J/A+AS/142/275 : Stellar activity of late-type stars (Strassmeier+ 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 12 F11.5 d BJD Barycentric Julian Date; BJD-2440000
16- 21 F6.2 m/s RV [-12.6/12.6] Radial velocity
27- 30 F4.2 m/s e_RV [0.4/1.6] Uncertainty on the radial velocity
42- 47 F6.4 --- SHK [0.16/0.21]? Flux measurement of the
CaII H&K lines
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Jul-2014