scholarly journals Orbital Period Refinement of CoRoT Planets with TESS Observations

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter Klagyivik ◽  
Hans J. Deeg ◽  
Szilárd Csizmadia ◽  
Juan Cabrera ◽  
Grzegorz Nowak
Keyword(s):  
Orbital Period ◽  
Space Mission ◽  
Future Generations ◽  
Large Uncertainty ◽  
Main Motivation ◽  
Transiting Planets

CoRoT was the first space mission dedicated to exoplanet detection. Operational between 2007 and 2012, this mission discovered 37 transiting planets, including CoRoT-7b, the first terrestrial exoplanet with a measured size. The precision of the published transit ephemeris of most of these planets has been limited by the relative short durations of the CoRoT pointings, which implied a danger that the transits will become unobservable within a few years due to the uncertainty of their future transit epochs. Ground-based follow-up observations of the majority of the CoRoT planets have been published in recent years. Between Dec. 2018 and Jan. 2021, the TESS mission in its sectors 6 and 33 re-observed those CoRoT fields that pointed towards the Galactic anti-center. These data permitted the identification of transits from nine of the CoRoT planets, and the derivation of precise new transit epochs. The main motivation of this study has been to derive precise new ephemerides of the CoRoT planets, in order to keep these planets’ transits observable for future generations of telescopes. The TESS data were analyzed for the presence of transits and the epochs of these re-observed transits were measured. The original CoRoT epochs, epochs from ground-based follow-up observations and those from TESS were collected. From these data, updated ephemerides are presented for nine transiting planets discovered by the CoRoT mission in its fields pointing towards the Galactic anti-center. In three cases (CoRoT-4b, 19b and 20b), transits that would have been lost for ground observations, due to the large uncertainty in the previous ephemeris, have been recovered. The updated ephemerides permit transit predictions with uncertainties of less than 30 min for observations at least until the year 2030. No significant transit timing variations were found in these systems.

scholarly journals The TOI-763 system: sub-Neptunes orbiting a Sun-like star

2020 ◽  
Vol 498 (3) ◽  
pp. 4503-4517
Author(s):  
M Fridlund ◽  
J Livingston ◽  
D Gandolfi ◽  
C M Persson ◽  
K W F Lam ◽  
...  
Keyword(s):  
Light Curve ◽  
Orbital Period ◽  
Planetary System ◽  
Space Mission ◽  
The Sun ◽  
Minimum Mass ◽  
Dwarf Star ◽  
Stellar Spectrum ◽  
Transit Signals

ABSTRACT We report the discovery of a planetary system orbiting TOI-763(aka CD-39 7945), a V = 10.2, high proper motion G-type dwarf star that was photometrically monitored by the TESS space mission in Sector 10. We obtain and model the stellar spectrum and find an object slightly smaller than the Sun, and somewhat older, but with a similar metallicity. Two planet candidates were found in the light curve to be transiting the star. Combining TESS transit photometry with HARPS high-precision radial velocity (RV) follow-up measurements confirm the planetary nature of these transit signals. We determine masses, radii, and bulk densities of these two planets. A third planet candidate was discovered serendipitously in the RV data. The inner transiting planet, TOI-763 b, has an orbital period of Pb  =  5.6 d, a mass of Mb  =  9.8 ± 0.8 M⊕, and a radius of Rb  =  2.37 ± 0.10 R⊕. The second transiting planet, TOI-763 c, has an orbital period of Pc  =  12.3 d, a mass of Mc  =  9.3 ± 1.0 M⊕, and a radius of Rc  =  2.87 ± 0.11 R⊕. We find the outermost planet candidate to orbit the star with a period of ∼48 d. If confirmed as a planet, it would have a minimum mass of Md  =  9.5 ± 1.6 M⊕. We investigated the TESS light curve in order to search for a mono transit by planet d without success. We discuss the importance and implications of this planetary system in terms of the geometrical arrangements of planets orbiting G-type stars.

scholarly journals A deeper meaning of sustainability: Insights from indigenous knowledge

2020 ◽  
Vol 7 (1) ◽  
pp. 77-93
Author(s):  
Fulvio Mazzocchi
Keyword(s):  
Indigenous Knowledge ◽  
Knowledge Systems ◽  
Future Generations ◽  
Main Motivation ◽  
Alternative Perspective ◽  
Western View ◽  
Different Cultures

This article argues that different cultures and their respective knowledge systems should partake to the sustainability debate. The focus is on insights that indigenous knowledge may provide, analyzing the principles which oversee indigenous relationship with nature, like reciprocity and caretaking. These principles move from a profound sense of unity and interconnectedness and put emphasis on the importance of giving back to nature. They offer an alternative perspective on sustainability that challenges the Western view. Such a view is still focused on maintaining the possibility of exploitation and embedded in a sense of separation from nature. The article discusses the need of creating a laboratory for sustainability, that is, a genuinely pluralist space in which multiple cultural expertise can interact and mutually enrich, yet maintaining their distinction and integrity. The main motivation of such an endevor should be to redefine the notion of sustainability in a more refined and thoughtful way: this is something vital for present and future generations.

Follow-up Photometry in Another Band Helps to Reduce Kepler’s False-positive Rates

2021 ◽  
Vol 162 (6) ◽  
pp. 258
Author(s):  
Mu-Tian Wang ◽  
Hui-Gen Liu ◽  
Jiapeng Zhu ◽  
Ji-Lin Zhou
Keyword(s):  
False Positive ◽  
Binary Systems ◽  
False Positives ◽  
Eclipsing Binaries ◽  
Identification Rate ◽  
Transiting Planets ◽  
Secondary Star ◽  
Band Depth ◽  
Depth Feature

Abstract The Kepler mission’s single-band photometry suffers from astrophysical false positives, most commonly of background eclipsing binaries (BEBs) and companion transiting planets (CTPs). Multicolor photometry can reveal the color-dependent depth feature of false positives and thus exclude them. In this work, we aim to estimate the fraction of false positives that cannot be classified by Kepler alone but can be identified from their color-dependent depth feature if a reference band (z, K s , and Transiting Exoplanet Survey Satellite (TESS)) is adopted in follow-up observation. We construct physics-based blend models to simulate multiband signals of false positives. Nearly 65%–95% of the BEBs and more than 80% of the CTPs that host a Jupiter-sized planet will show detectable depth variations if the reference band can achieve a Kepler-like precision. The K s band is most effective in eliminating BEBs exhibiting features of any depth, while the z and TESS bands are better for identifying giant candidates, and their identification rates are more sensitive to photometric precision. Given the radius distribution of planets transiting the secondary star in binary systems, we derive a formalism to calculate the overall identification rate for CTPs. By comparing the likelihood distribution of the double-band depth ratio for BEB and planet models, we calculate the false-positive probability (FPP) for typical Kepler candidates. Additionally, we show that the FPP calculation helps distinguish the planet candidate’s host star in an unresolved binary system. The framework of the analysis in this paper can be easily adapted to predict the multicolor photometric yield for other transit surveys, especially TESS.

scholarly journals Observations of the transiting planet TrES-2 with the AIU Jena telescope in Großschwabhausen

2008 ◽  
Vol 4 (S253) ◽  
pp. 436-439 ◽  
Author(s):  
S. Raetz ◽  
M. Mugrauer ◽  
T. O. B. Schmidt ◽  
T. Roell ◽  
T. Eisenbeiss ◽  
...  
Keyword(s):  
High Precision ◽  
Orbital Period ◽  
Ccd Camera ◽  
Light Curves ◽  
Orbital Parameters ◽  
Transiting Planets ◽  
Photometric Monitoring ◽  
Cassegrain Telescope ◽  
Parent Star ◽  
Planetary Transits

AbstractWe have started high precision photometric monitoring observations at the AIU Jena observatory in Großschwabhausen near Jena in fall 2006. We used a 25.4cm Cassegrain telescope equipped with a CCD-camera mounted piggyback on a 90cm telescope. To test the attainable photometric precision, we observed stars with known transiting planets. We could recover all planetary transits observed by us.We observed the parent star of the transiting planet TrES-2 over a longer period in Großschwabhausen. Between March and November 2007 seven different transits and almost a complete orbital period were analyzed. Overall, in 31 nights of observation 3423 exposures (in total 57.05h of observation) of the TrES-2 parent star were taken. Here, we present our methods and the resulting light curves. Using our observations we could improve the orbital parameters of the system.

scholarly journals Prospects for detecting the astrometric signature of Barnard’s Star b

2019 ◽  
Vol 623 ◽  
pp. A10 ◽  
Author(s):  
L. Tal-Or ◽  
S. Zucker ◽  
I. Ribas ◽  
G. Anglada-Escudé ◽  
A. Reiners
Keyword(s):  
Orbital Period ◽  
Mass Range ◽  
Periodic Signal ◽  
Wide Field ◽  
Space Telescope ◽  
Single Epoch ◽  
Low Amplitude ◽  
Orbital Orientation ◽  
True Mass

A low-amplitude periodic signal in the radial velocity (RV) time series of Barnard’s Star was recently attributed to a planetary companion with a minimum mass of ~3.2 M⊕ at an orbital period of ~233 days. The relatively long orbital period and the proximity of Barnard’s Star to the Sun raises the question whether the true mass of the planet can be constrained by accurate astrometric measurements. By combining the assumption of an isotropic probability distribution of the orbital orientation with the RV-analysis results, we calculated the probability density function of the astrometric signature of the planet. In addition, we reviewed the astrometric capabilities and limitations of current and upcoming astrometric instruments. We conclude that Gaia and the Hubble Space Telescope (HST) are currently the best-suited instruments to perform the astrometric follow-up observations. Taking the optimistic estimate of their single-epoch accuracy to be ~30μas, we find a probability of ~10% to detect the astrometric signature of Barnard’s Star b with ~50 individual-epoch observations. In case of no detection, the implied mass upper limit would be ~8 M⊕, which would place the planet in the super-Earth mass range. In the next decade, observations with the Wide-Field Infrared Space Telescope (WFIRST) may increase the prospects of measuring the true mass of the planet to ~99%.

scholarly journals Search for Transiting Exoplanets with HATNet

2008 ◽  
Vol 4 (S253) ◽  
pp. 21-27
Author(s):  
G. Á. Bakos ◽  
R. W. Noyes ◽  
G. Kovács ◽  
D. W. Latham ◽  
G. Torres ◽  
...  
Keyword(s):  
High Resolution ◽  
Extrasolar Planets ◽  
Detection Efficiency ◽  
False Alarms ◽  
Wide Field ◽  
Transiting Planets

AbstractHATNet is a network of six identical, fully automated wide field telescopes, four of which are located in Arizona, and two at Hawaii. The purpose of the network is to search for transiting extrasolar planets around relatively bright stars (8 <I< 12). The longitudinal coverage of 3.5 hours greatly enhances transit detection efficiency. HATNet has been operational since 2004, and has taken more than 1/2 million science frames at 5-min integrations, covering about 7% of the sky. Photometric precision reaches 3mmag rms at 5.5 min cadence atI≈ 8, and is 1% atI≈ 11.3. Hundreds of transitcandidateshave been detected in the data, and have been subject to vigorous follow-up by various 1m-class facilities, both spectroscopy and follow-up photometry. A fraction of the candidates that have survived these steps as not being false alarms have been observed by high resolution and precision spectrographs (primarily Keck/HIRES), to confirm their planetary nature and characterize their properties. So far nine transiting planets have been reported, making HATNet a very successful survey.

scholarly journals The photometric follow-up observations for transiting exoplanet XO-2b

2010 ◽  
Vol 6 (S276) ◽  
pp. 426-427
Author(s):  
Sheng-hong Gu ◽  
Andrew Collier Cameron ◽  
Xiao-bin Wang ◽  
Xiang-song Fang ◽  
Dong-tao Cao ◽  
...  
Keyword(s):  
Orbital Period ◽  
Light Curves ◽  
Mcmc Algorithm ◽  
System Parameters

AbstractFour new transit light curves of XO-2b obtained in 2008 and 2009, are analyzed by using MCMC algorithm, and the system parameters are derived. The result demonstrates that the orbital period of the system obtained from new observations is almost the same as Burke et al.'s one (2007), which does not confirm the result of Fernandez et al. (2009).

scholarly journals Swift/XRT Deep Galactic Plane Survey Discovery of a New Intermediate Polar Cataclysmic Variable, Swift J183920.1-045350

2021 ◽  
Vol 923 (2) ◽  
pp. 243
Author(s):  
Nicholas M. Gorgone ◽  
Patrick A. Woudt ◽  
David Buckley ◽  
Koji Mukai ◽  
Chryssa Kouveliotou ◽  
...  
Keyword(s):  
Orbital Period ◽  
Galactic Plane ◽  
Emission Lines ◽  
Cataclysmic Variable ◽  
Optical Photometry ◽  
X Ray ◽  
Common Features ◽  
Spin Period ◽  
Long Baseline

Abstract We report on the Swift/XRT Deep Galactic Plane Survey discovery and multiwavelength follow-up observations of a new intermediate polar (IP) cataclysmic variable, Swift J183920.1-045350. A 449.7 s spin period is found in XMM-Newton and NuSTAR data, accompanied by a 459.9 s optical period that is most likely the synodic, or beat period, produced from a 5.6 hr orbital period. The orbital period is seen with moderate significance in independent long-baseline optical photometry observations taken with the ZTF and SAAO telescopes. We find that the X-ray pulse fraction of the source decreases with increasing energy. The X-ray spectra are consistent with the presence of an Fe emission line complex with both local and interstellar absorption. In the optical spectra, strong Hα, H i, He i, and He ii emission lines are observed, all common features in magnetic CVs. The source properties are thus typical of known IPs, with the exception of its estimated distance of 2.26 − 0.83 + 1.93 kpc, which is larger than typical, extending the reach of the CV population in our Galaxy.

scholarly journals Detection and Doppler monitoring of K2-285 (EPIC 246471491), a system of four transiting planets smaller than Neptune

2019 ◽  
Vol 623 ◽  
pp. A41 ◽  
Author(s):  
E. Palle ◽  
G. Nowak ◽  
R. Luque ◽  
D. Hidalgo ◽  
O. Barragán ◽  
...  
Keyword(s):  
Bulk Composition ◽  
Velocity Measurements ◽  
Good Test ◽  
Transiting Planets ◽  
Atmospheric Escape ◽  
Outer Planets ◽  
Upper Limits ◽  
The Masses ◽  
Better Than

Context. The Kepler extended mission, also known as K2, has provided the community with a wealth of planetary candidates that orbit stars typically much brighter than the targets of the original mission. These planet candidates are suitable for further spectroscopic follow-up and precise mass determinations, leading ultimately to the construction of empirical mass-radius diagrams. Particularly interesting is to constrain the properties of planets that are between Earth and Neptune in size, the most abundant type of planet orbiting Sun-like stars with periods of less than a few years. Aims. Among many other K2 candidates, we discovered a multi-planetary system around EPIC 246471491, referred to henceforth as K2-285, which contains four planets, ranging in size from twice the size of Earth to nearly the size of Neptune. We aim here at confirming their planetary nature and characterizing the properties of this system. Methods. We measure the mass of the planets of the K2-285 system by means of precise radial-velocity measurements using the CARMENES spectrograph and the HARPS-N spectrograph. Results. With our data we are able to determine the mass of the two inner planets of the system with a precision better than 15%, and place upper limits on the masses of the two outer planets. Conclusions. We find that K2-285b has a mass of Mb = 9.68−1.37+1.21 M⊕ and a radius of Rb = 2.59−0.06+0.06 R⊕, yielding a mean density of ρb = 3.07−0.45+0.45 g cm−3, while K2-285c has a mass of Mc = 15.68−2.13+2.28 M⊕, radius of Rc = 3.53−0.08+0.08 R⊕, and a mean density of ρc = 1.95−0.28+0.32 g cm−3. For K2-285d (Rd = 2.48−0.06+0.06 R⊕) and K2-285e (Re = 1.95−0.05+0.05 R⊕), the upper limits for the masses are 6.5 M⊕ and 10.7 M⊕, respectively. The system is thus composed of an (almost) Neptune-twin planet (in mass and radius), two sub-Neptunes with very different densities and presumably bulk composition, and a fourth planet in the outermost orbit that resides right in the middle of the super-Earth/sub-Neptune radius gap. Future comparative planetology studies of this system would provide useful insights into planetary formation, and also a good test of atmospheric escape and evolution theories.

Ethical issues raised by intergenerational monitoring in clinical trials of germline gene modification

2020 ◽  
pp. medethics-2020-106095
Author(s):  
Austen Yeager
Keyword(s):  
Clinical Trials ◽  
Trial Design ◽  
Gene Editing ◽  
Ethical Issues ◽  
Clinical Trial Design ◽  
Careful Consideration ◽  
Future Generations ◽  
Germline Gene ◽  
Gene Modification

As research involving gene editing continues to advance, we are headed in the direction of being able to modify the human germline. Should we reach a point where an argument can be made that the benefits of preventing unborn children and future generations from inheriting genetic conditions that cause tremendous suffering outweigh the risks associated with altering the human germline, the next step will be to design clinical trials using this technology in humans. These clinical trials will likely require careful follow-up and monitoring of future generations born with altered genes. This paper addresses some of the ethical issues raised by intergenerational monitoring and sets out to show that these issues can be avoided with careful consideration and clinical trial design.

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