Planets around evolved intermediate-mass stars - I. Two substellar companions in the open clusters NGC 2423 and NGC 4349

By C. Lovis, M. Mayor. 2007

193 citations recorded by the source corpus.

Context. Many efforts are being made to characterize extrasolar planetary systems and unveil the fundamental mechanisms of planet formation. An important aspect of the problem, which remains largely unknown, is to understand how the planet formation process depends on the mass of the parent star. In particular, as most planets discovered to date orbit a solar-mass primary, little is known about planet formation around more massive stars. Aims. To investigate this point, we present first results from a radial velocity planet search around red giants in the clump of intermediate-age open clusters. We choose clusters harbouring red giants with masses between 1.5 and 4 M� , using the well-known cluster parameters to accurately determine the stellar masses. We are therefore exploring a poorly-known domain of primary masses, which will bring new insights into the properties of extrasolar planetary systems. Methods. We follow a sample of about 115 red giants with the Coralie and HARPS spectrographs to obtain high-precision radial velocity (RV) measurements and detect giant planets around these stars. We use bisector and activity index diagnostics to distinguish between planetary-induced RV variations and stellar photospheric jitter. Results. We present the discoveries of a giant planet and a brown dwarf in the open clusters NGC 2423 and NGC 4349, orbiting the 2.4 M� -star NGC 2423 No. 3 (TYC 5409-2156-1) and the 3.9 M� -star NGC 4349 No. 127 (TYC 8975-2606-1). These low-mass companions have orbital periods of 714 and 678 days and minimum masses of 10.6 and 19.8 MJup, respectively. Combined with the other known planetary systems, these detections indicate that the frequency of massive planets is higher around intermediate-mass stars, and therefore probably scales with the mass of the protoplanetary disk.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/513fee31a30b112353eaa86788b8623044ba0057

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In Astronomy and Astrophysics

1. C. Mordasini
2. Debra A. Fischer
3. Nuno C. Santos
4. J. Johnson
5. M. Mayor
6. G. Marcy
7. B. Bowler
8. S. Udry

In Instrumentation

1. B. Bowler
2. J. Johnson
3. Debra A. Fischer
4. G. Marcy
5. Nuno C. Santos
6. M. Mayor
7. Jason T. Wright
8. R. P. Butler

Citations in the corpus

• A New Planet around an M Dwarf: Revealing a Correlation between Exoplanets and Stellar Mass (2007, background): “Our preliminary results and those of Lovis & Mayor (2007) reveal a positive correlation between the mass of stars and the likelihood that they harbor giant planets.”
• ON THE METAL RICHNESS OF M DWARFS WITH PLANETS (2009, background): “Abundance analyses of the stellar samples encompassed by Doppler surveys show that the occurrence rate of detectable planets correlates strongly with stellar metallicity (Santos et al. 2004; Fischer & Valenti 2005) and stellar mass (Lovis & Mayor 2007; Johnson et al. 2007).”
• A NEAR-INFRARED SPECTROSCOPIC STUDY OF YOUNG FIELD ULTRACOOL DWARFS (2013, background): “Is NGC 4349 127 b, a 20 MJup radial velocity companion (Lovis & Mayor 2007) to an intermediatemass star (3.9 M⊙), best characterized as a brown dwarf?”
• The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “Before M dwarfs were revealed to host small planets (< 4 R⊕) in abundance (which we describe in detail in Section 3.5), their dearth of gas giants established them as comparatively poor planet hosts (Laws et al., 2003; Johnson et al., 2007; Lovis & Mayor, 2007; Johnson et al., 2010a).”
• A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192 (2008, background): “Gas giant planets have been found in orbit around stars of all these types (Butler et al. 2006; Sato et al. 2007; Johnson et al. 2007; Niedzielski et al. 2007; Lovis & Mayor 2007), but they appear to be increasingly rare in orbit around low-mass stars.”
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs - I. New atmospheric parameters and masses for 48 stars with planets (2013, background): “Higher mass stars, on the other hand, seem to have a higher frequency of orbiting giant planets (Lovis & Mayor 2007; Johnso et al. 2007a).”
• Imaging Extrasolar Giant Planets (2016, background): “…a higher giant planet occurrence rate around massive stars analogous to the well-established correlation at small separations (Johnson et al. 2007; Lovis & Mayor 2007; Johnson et al. 2010; Bowler et al. 2010b), this trend is not yet statistically significant at wide orbital distances and requires…”
• PLANETS AROUND LOW-MASS STARS (PALMS). IV. THE OUTER ARCHITECTURE OF M DWARF PLANETARY SYSTEMS (2014, background): “…trend between planet occurrence rate and stellar host mass (Butler et al. 2004; Endl et al. 2006; Butler et al. 2006; Johnson et al. 2007; Lovis & Mayor 2007; Cumming et al. 2008; Bowler et al. 2010; Bonfils et al. 2013; Gaidos et al. 2013) lends support to the core accretion plus…”
• Extrasolar planet population synthesis - IV. Correlations with disk metallicity, mass, and lifetime (2012, background): “(5) Giant planets are more frequently found orbiting A stars than orbiting solar-like stars, and are also more massive (Lovis & Mayor 2007; Bowler et al. 2010) on average.”
• Extrasolar planet population synthesis - II. Statistical comparison with observations (2009, background): “…high mass end this could be related to the fact that the Nobsreal = 32 observational comparison sample only includes companions if their mass is smaller than 20 MX, while we do not use such a criterion, so that we might should add some brown dwarf candidates, as suggested by Lovis & Mayor (2007).”
• RETIRED A STARS AND THEIR COMPANIONS. III. COMPARING THE MASS–PERIOD DISTRIBUTIONS OF PLANETS AROUND A-TYPE STARS AND SUN-LIKE STARS (2009, methodology): “…and giants (Frink et al. 2002, Setiawan et al. 2003a, Sato et al. 2005b; Johnson et al. 2006, Niedzielski et al. 2007, Döllinger et al. 2007, Lovis & Mayor 2007, Liu et al. 2009), although at least one survey is targeting their main sequence progenitors (Galland et al. 2005; Lagrange et…”
• THE FORMATION MECHANISM OF GAS GIANTS ON WIDE ORBITS (2009, unknown): “Lovis & Mayor (2007) also found the highest average planet mass around A stars vs.”
• THE ORBITAL EVOLUTION OF GAS GIANT PLANETS AROUND GIANT STARS (2009, background): “The frequency of planets seems also to be higher around intermediate-mass stars (Lovis & Mayor 2007; Johnson et al. 2007b).”
• Extrasolar planets and brown dwarfs around A-F type stars. VI. High precision RV survey of early type dwarfs with HARPS (2008, background): “…to study “retired” early-type instead, either low-mass (≤1.6 M ) giants, intermediate-mass (1.6−2 M ) subgiants, or clump giants (1.7−3.9 M ) (see e.g., Hatzes et al. 2005; Niedzielski et al. 2007; Johnson et al. 2006, 2007; Lovis & Mayor 2007; Article published by EDP Sciences Sato et al. 2008).”
• FUNDAMENTAL PROPERTIES OF KEPLER PLANET-CANDIDATE HOST STARS USING ASTEROSEISMOLOGY (2013, unknown): “…surveys have yielded two important correlations: gas giant planets occur more frequently around stars of high metallicity (Gonzalez 1997; Santos et al. 2004; Fischer & Valenti 2005) and around more massive stars (Laws et al. 2003; Johnson et al. 2007; Lovis & Mayor 2007; Johnson et al. 2010).”