Non-Detection of the Putative Substellar Companion to Hd 149382

Norris, J.; Wright, Jason T.; Wade, Richard A.; Mahadevan, Suvrath; Gettel, Sara

doi:10.1088/0004-637x/743/1/88

Cited by 10 publications

(9 citation statements)

References 29 publications

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“…Although this early result could not be confirmed by other groups (Norris et al 2011), we soon found much better candidates. The selection criteria of the MUCHFUSS project not only single out massive companions but also companions with very low masses in extremely short orbits.…”

Section: Substellar Companionscontrasting

confidence: 71%

Hot subdwarfs: Small stars marking important events in stellar evolution: Ludwig Biermann Award Lecture 2014

Geier¹

2015

Astron Nachr

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Hot subdwarfs are considered to be the compact helium cores of red giants which lost almost their entire hydrogen envelope. What causes this enormous mass loss is still unclear. Binary interactions are invoked, and a significant fraction of the hot subdwarf population is indeed found in close binaries. In a large project we search for close binary sdBs with the most and the least massive companions. Significantly enhancing the known sample of close binary sdBs we performed the first comprehensive study of this population. Triggered by the discovery of two sdB binaries with close brown dwarf companions in the course of this project, we were able to show that the interaction of stars with substellar companions is an important channel to form sdB stars. Finally, we discovered a unique and very compact binary system consisting of an sdB and a massive white dwarf which qualifies as a progenitor candidate for a supernova of type Ia. In addition to that, we could connect those explosions to the class of hypervelocity hot subdwarf stars which we consider as the surviving companions of such events. Being the stripped cores of red giants, hot subdwarfs turned out to be important markers of peculiar events in stellar evolution ranging all the way from star-planet interactions to the progenitors of stellar explosions used to measure the expansion of our Universe.

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Section: Substellar Companionscontrasting

confidence: 71%

Hot subdwarfs: Small stars marking important events in stellar evolution: Ludwig Biermann Award Lecture 2014

Geier¹

2015

Astron Nachr

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“…Although we adopted the rough wavelength calibration used for planet search work, we did not attempt to use this calibration to measure our radial velocities. Rather, we extracted radial velocities in pixel space by crosscorrelating the spectra of our candidate cluster members with those of our observed RV standard stars (a similar pixel-space cross-correlation method was employed by Norris et al (2011)). To reduce the errors introduced by comparing two stars of different spectral types, we paired each candidate member to an RV standard star that minimized the difference between their V − J colors (∆(V − J)), with V − J = 0.8 for the bluest standard star and V − J = 2.4 for the reddest.…”

Section: Radial Velocity Determinationmentioning

confidence: 99%

Ruprecht 147: The Oldest Nearby Open Cluster as a New Benchmark for Stellar Astrophysics

Curtis

Wolfgang

Wright

et al. 2013

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102

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Ruprecht 147 is a hitherto unappreciated open cluster that holds great promise as a standard in fundamental stellar astrophysics. We have conducted a radial velocity survey of astrometric candidates with Lick, Palomar, and MMT observatories and have identified over 100 members, including 5 blue stragglers, 11 red giants, and 5 double-lined spectroscopic binaries (SB2s). We estimate the cluster metallicity from spectroscopic analysis, using Spectroscopy Made Easy (SME), and find it to be [M/H] = +0.07 ± 0.03. We have obtained deep CFHT/MegaCam g ′ r ′ i ′ z ′ photometry and fit Padova isochrones to the (g ′ − i ′ ) and 2MASS (J − K S ) CMDs, using the τ 2 maximum-likelihood procedure of Naylor (2009), and an alternative method using 2D cross-correlations developed in this work. We find best fits for isochrones at age t = 2.5 ± 0.25 Gyr, m − M = 7.35 ± 0.1, and A V = 0.25 ± 0.05, with additional uncertainty from the unresolved binary population and possibility of differential extinction across this large cluster. The inferred age is heavily dependent by our choice of stellar evolution model: fitting Dartmouth and PARSEC models yield age parameters of 3 Gyr and 3.25 Gyr respectively. At ∼300 pc and ∼3 Gyr, Ruprecht 147 is by far the oldest nearby star cluster.

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“…However, the attribution of these signals to exoplanets is debatable (Krzesinski 2015;Blokesz et al 2019). Using the RV method, Geier et al (2009) announced the discovery of a close-in (P orb = 2.4 days) planet of several Jupiter masses around HD 149382, but this was ruled out by high-precision RV measurements obtained with the Hobby-Eberly Telescope spectrograph, which excluded the presence of almost any substellar companion with P orb < 28 days and M sin i 1M Jup (Norris et al 2011).…”

Section: Search For Planets Around Hot Subdwarfs: Current Statusmentioning

confidence: 99%

A search for transiting planets around hot subdwarfs

Grootel

Pozuelos

Thuillier

et al. 2021

A&A

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Context. Hot subdwarfs experienced strong mass loss on the red giant branch (RGB) and are now hot and small He-burning objects. These stars constitute excellent opportunities for addressing the question of the evolution of exoplanetary systems directly after the RGB phase of evolution. Aims. In this project we aim to perform a transit survey in all available light curves of hot subdwarfs from space-based telescopes (Kepler, K2, TESS, and CHEOPS) with our custom-made pipeline SHERLOCK in order to determine the occurrence rate of planets around these stars as a function of orbital period and planetary radius. We also aim to determine whether planets that were previously engulfed in the envelope of their red giant host star can survive, even partially, as a planetary remnant. Methods. For this first paper, we performed injection-and-recovery tests of synthetic transits for a selection of representative Kepler, K2, and TESS light curves to determine which transiting bodies in terms of object radius and orbital period we will be able to detect with our tools. We also provide estimates for CHEOPS data, which we analyzed with the pycheops package. Results. Transiting objects with a radius ≲1.0 R⊕ can be detected in most of the Kepler, K2, and CHEOPS targets for the shortest orbital periods (1 d and shorter), reaching values as low as ~0.3 R⊕ in the best cases. Sub-Earth-sized bodies are only reached for the brightest TESS targets and for those that were observed in a significant number of sectors. We also give a series of representative results for larger planets at greater distances, which strongly depend on the target magnitude and on the length and quality of the data. Conclusions. The TESS sample will provide the most important statistics for the global aim of measuring the planet occurrence rate around hot subdwarfs. The Kepler, K2, and CHEOPS data will allow us to search for planetary remnants, that is, very close and small (possibly disintegrating) objects.

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Non-Detection of the Putative Substellar Companion to Hd 149382

Cited by 10 publications

References 29 publications

Hot subdwarfs: Small stars marking important events in stellar evolution: Ludwig Biermann Award Lecture 2014

Hot subdwarfs: Small stars marking important events in stellar evolution: Ludwig Biermann Award Lecture 2014

Ruprecht 147: The Oldest Nearby Open Cluster as a New Benchmark for Stellar Astrophysics

A search for transiting planets around hot subdwarfs

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