We report the discovery of KELT-18b, a transiting hot Jupiter in a 2.87-day orbit around the bright (V = 10.1), hot, F4V star BD+60 1538 (TYC 3865-1173-1). We present follow-up photometry, ...spectroscopy, and adaptive optics imaging that allow a detailed characterization of the system. Our preferred model fits yield a host stellar temperature of K and a mass of , situating it as one of only a handful of known transiting planets with hosts that are as hot, massive, and bright. The planet has a mass of , a radius of , and a density of , making it one of the most inflated planets known around a hot star. We argue that KELT-18b's high temperature and low surface gravity, which yield an estimated ∼600 km atmospheric scale height, combined with its hot, bright host, make it an excellent candidate for observations aimed at atmospheric characterization. We also present evidence for a bound stellar companion at a projected separation of ∼1100 au, and speculate that it may have contributed to the strong misalignment we suspect between KELT-18's spin axis and its planet's orbital axis. The inferior conjunction time is 2457542.524998 0.000416 (BJDTDB) and the orbital period is 2.8717510 0.0000029 days. We encourage Rossiter-McLaughlin measurements in the near future to confirm the suspected spin-orbit misalignment of this system.
KPS-1b Burdanov, Artem; Benni, Paul; Sokov, Eugene ...
Publications of the Astronomical Society of the Pacific,
07/2018, Letnik:
130, Številka:
989
Journal Article
Recenzirano
We report the discovery of the transiting hot Jupiter KPS-1b. This exoplanet orbits a V = 13.0 K1-type mainsequence star every 1.7 days, has a mass of
1.090
−
0.087
+
0.086
M
Jup and a radius of
1.03
...−
0.12
+
0.13
R
Jup. The discovery was made by the prototype Kourovka Planet Search (KPS) project, which used wide-field CCD data gathered by an amateur astronomer using readily available and relatively affordable equipment. Here we describe the equipment and observing technique used for the discovery of KPS-1b, its characterization with spectroscopic observations by the SOPHIE spectrograph and with high-precision photometry obtained with 1 m class telescopes. We also outline the KPS project evolution into the Galactic Plane eXoplanet survey. The discovery of KPS-1b represents a new major step of the contribution of amateur astronomers to the burgeoning field of exoplanetology.
Abstract
We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (
V
= 8.3 mag,
K
= 7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a
...T
eff
=
K, a mass of
M
*
=
M
⊙
, a radius of
R
*
= 1.506 ± 0.022
R
⊙
, and an age of
Gyr. Its planetary companion (KELT-24 b) has a radius of
R
P
= 1.272 ± 0.021
R
J
and a mass of
M
P
=
M
J
, and from Doppler tomographic observations, we find that the planet’s orbit is well-aligned to its host star’s projected spin axis (
). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.
We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V=8.3 mag, K=7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a ...Teff=-+65094950K, a mass of M*=+1.4600.0590.055Me, a radius of R*=1.506±0.022Re, and an age of +0.780.420.61Gyr. Its planetary companion (KELT-24 b) has a radius of RP=1.272±0.021RJ and a mass of MP=-+5.180.220.21MJ, and from Doppler tomographic observations, we find that the planet’s orbit is well aligned to its host star’s projected spin axis (l=-+2.63.65.1). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.
The nova M31N 2023-11f (2023yoa) has been recently identified as the second eruption of a previously recognized nova, M31N 2013-10c, establishing the latter object as the 21st recurrent nova system ...thus far identified in M31. Here we present well sampled \(R\)-band lightcurves of both the 2013 and 2023 eruptions of this system. The photometric evolution of each eruption was quite similar as expected for the same progenitor system. The 2013 and 2023 eruptions each reached peak magnitudes just brighter than \(R\sim16\), with fits to the declining branches of the eruptions yielding times to decline by two magnitudes of \(t_2(R)=5.5\pm1.7\) and \(t_2(R)=3.4\pm1.5\) days, respectively. M31N 2013-10c has an absolute magnitude at peak, \(M_R=-8.8\pm0.2\), making it the most luminous known recurrent nova in M31.
Transit Timing Variations (TTVs) can be induced by a range of physical
phenomena, including planet-planet interactions, planet-moon interactions, and
stellar activity. Recent work has shown that ...roughly half of moons would induce
fast TTVs with a short period in the range of two-to-four orbits of its host
planet around the star. An investigation of the Kepler TTV data in this period
range identified one primary target of interest, Kepler-1513 b. Kepler-1513 b
is a $8.05^{+0.58}_{-0.40}$ $R_\oplus$ planet orbiting a late G-type dwarf at
$0.53^{+0.04}_{-0.03}$ AU. Using Kepler photometry, this initial analysis
showed that Kepler-1513 b's TTVs were consistent with a moon. Here, we report
photometric observations of two additional transits nearly a decade after the
last Kepler transit using both ground-based observations and space-based
photometry with TESS. These new transit observations introduce a previously
undetected long period TTV, in addition to the original short period TTV
signal. Using the complete transit dataset, we investigate whether a
non-transiting planet, a moon, or stellar activity could induce the observed
TTVs. We find that only a non-transiting perturbing planet can reproduce the
observed TTVs. We additionally perform transit origami on the Kepler
photometry, which independently applies pressure against a moon hypothesis.
Specifically, we find that Kepler-1513 b's TTVs are consistent with an exterior
non-transiting $\sim$Saturn mass planet, Kepler-1513 c, on a wide orbit,
$\sim$5$\%$ outside a 5:1 period ratio with Kepler-1513 b. This example
introduces a previously unidentified cause for planetary interlopers in the
exomoon corridor, namely an insufficient baseline of observations.
Studying the relative orientations of the orbits of exoplanets and wide-orbiting binary companions (semimajor axis greater than 100 AU) can shed light on how planets form and evolve in binary ...systems. Previous observations by multiple groups discovered a possible alignment between the orbits of visual binaries and the exoplanets that reside in them. In this study, using data from \textit{Gaia} DR3 and TESS, we confirm the existence of an alignment between the orbits of small planets \((R<6 R_\oplus)\) and binary systems with semimajor axes below 700 AU (\(p=10^{-6}\)). However, we find no statistical evidence for alignment between planet and binary orbits for binary semimajor axes greater than 700 AU, and no evidence for alignment of large, closely-orbiting planets (mostly hot Jupiters) and binaries at any separation. The lack of orbital alignment between our large planet sample and their binary companions appears significantly different from our small planet sample, even taking into account selection effects. Therefore, we conclude that any alignment between wide-binaries and our sample of large planets (predominantly hot Jupiters) is probably not as strong as what we observe for small planets in binaries with semimajor axes less than 700 AU. The difference in the alignment distribution of hot Jupiters and smaller planets may be attributed to the unique evolutionary mechanisms occuring in systems that form hot Jupiters, including potentially destabilizing secular resonances that onset as the protoplanetary disk dissipates and high-eccentricity migration occurring after the disk is gone.
We present a dedicated transit and radial velocity survey of planets orbiting subgiant stars observed by the TESS Mission. Using $\sim$$16\( nights on Keck/HIRES, we confirm and characterize \)12\( ...new transiting planets -- \)\rm TOI-329\,b\(, \)\rm HD\,39688\,b\( (\)\rm TOI-480\(), \)\rm TOI-603\,b\(, \)\rm TOI-1199\,b\(, \)\rm TOI-1294\,b\(, \)\rm TOI-1439\,b\(, \)\rm TOI-1605\,b\(, \)\rm TOI-1828\,b\(, \)\rm HD\,148193\,b\( (\)\rm TOI-1836\(), \)\rm TOI-1885\,b\(, \)\rm HD\,83342\,b\( (\)\rm TOI-1898\(), \)\rm TOI-2019\,b\( -- and provide updated properties for 9 previously confirmed TESS subgiant systems (\)\rm TOI-197\(, \)\rm TOI-954\(, \)\rm TOI-1181\(, \)\rm TOI-1296\(, \)\rm TOI-1298\(, \)\rm TOI-1601\(, \)\rm TOI-1736\(, \)\rm TOI-1842\(, \)\rm TOI-2145\(). We also report the discovery of an outer, non-transiting planet, \)\rm TOI-1294\,c\( (\)P=160.1\pm2.5\( days, \)M_{\mathrm{p}}=148.3^{+18.2}_{-16.4} \,M_{\oplus}\(), and three additional stars with long-term RV trends. We find that at least \)19\pm8\%\( of subgiants in our sample of \)21\( stars have outer companions, comparable to main-sequence stars. We perform a homogeneous analysis of the stars and planets in the sample, with median uncertainties of \)3\%\(, \)8\%\( and \)15\%\( for planet radii, masses and ages, doubling the number of known planets orbiting subgiant stars with bulk densities measured to better than \)10\%$. We observe a dearth of giant planets around evolved stars with short orbital periods, consistent with tidal dissipation theories that predict the rapid inspiral of planets as their host stars leave the main sequence. We note the possible evidence for two distinct classes of hot Jupiter populations, indicating multiple formation channels to explain the observed distributions around evolved stars. Finally, continued RV monitoring of planets in this sample will provide a more comprehensive understanding of demographics for evolved planetary systems.
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