KELT Results

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Re: KELT Results

Post by Stalker on 10th September 2015, 8:23 am

I guess a bot can easily tell us wich exoplanet is in wich contellation tanks to AlladinLit for example.

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Re: KELT Results

Post by Lazarus on 1st October 2015, 1:09 pm

More KELT results...

Rodriguez et al. "KELT-14b and KELT-15b: An Independent Discovery of WASP-122b and a New Hot Jupiter"
http://arxiv.org/abs/1509.08953

KELT-15b is the new one.
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Re: KELT Results

Post by Sirius_Alpha on 1st October 2015, 8:30 pm

Here's KELT-4Ab. The host is the brightest in a triple system.
http://arxiv.org/abs/1510.00015

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Re: KELT Results

Post by Edasich on 2nd October 2015, 4:57 am

Nice to see more KELT exoplanets released to fill the "numerical gap".
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Re: KELT Results

Post by Lazarus on 2nd October 2015, 3:43 pm

Third known transiting planet in a hierarchical triple star system? Wouldn't have guessed the number was that low...
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Re: KELT Results

Post by Stalker on 3rd October 2015, 3:29 pm

I reference 1977 exoplanets (close <25Mj companions around stars), 28 wide planetary masse companions, 4 brown dwarf planets. All those are "EPE friendly" planets and the total is 2009. I Just realised we know more than 2000 exoplanets!

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Re: KELT Results

Post by Sirius_Alpha on 6th July 2016, 9:08 pm

KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V=8 Subgiant HD 93396
http://arxiv.org/abs/1607.01755

We report the discovery of a transiting exoplanet, KELT-11b, orbiting the bright (V=8.0) subgiant HD 93396. A global analysis of the system shows that the host star is an evolved subgiant star with Teff=5370±51 K, M∗=1.438+0.061−0.052M⊙, R∗=2.72+0.21−0.17R⊙, log g∗=3.727+0.040−0.046, and [Fe/H]=0.180±0.075. The planet is a low-mass gas giant in a P=4.736529±0.00006 day orbit, with MP=0.195±0.018MJ, RP=1.37+0.15−0.12RJ, ρP=0.093+0.028−0.024 g cm−3, surface gravity log gP=2.407+0.080−0.086, and equilibrium temperature Teq=1712+51−46 K. KELT-11 is the brightest known transiting exoplanet host in the southern hemisphere by more than a magnitude, and is the 6th brightest transit host to date. The planet is one of the most inflated planets known, with an exceptionally large atmospheric scale height (2763 km), and an associated size of the expected atmospheric transmission signal of 5.6%. These attributes make the KELT-11 system a valuable target for follow-up and atmospheric characterization, and it promises to become one of the benchmark systems for the study of inflated exoplanets.

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Re: KELT Results

Post by Shellface on 7th July 2016, 3:03 pm

This is an interesting one. It dethrones HAT-P-11 b as the shallowest transit signal discovered from the ground. It is also one of the few short-period planets known around such evolved stars, though the low mass makes calling it a hot jupiter a stretch.

Something very notable is that the star had been observed by HIRES since 2007, but the RV variability was too modest to be recognised. As they put it:

This planet was discovered due to the combination of both transit and RV survey data. The KELT survey observations (§2.1) and follow-
up photometry (§2.2) enabled us to identify this target as a good candidate, but with such a low mass planet, our typical follow-up methods to obtain an RV orbit would have been extremely hard-pressed to enable dynamical confirmation purely through follow-up RV observations. However, the addition of the CPS survey data provided the evidence that this was a real planet, prompting us to gather the additional APF observations to enable reliable confirmation. Furthermore, the CPS RV observations by themselves were not sufficient to verify HD 93396 as a planet host without the accompanying transit evidence from KELT. We believe that this synergy between multiple types of survey data will be of great value over the next several years, especially with the expected launch of the TESS mission and availability of nearly all-sky high precision photometry.
I expect a significant number of similar results due to TESS, down to the low-mass planet range. All current RV surveys have stars with few observations and little RV variability that appear to be uninteresting, but TESS will have the opportunity to (literally) shed light on some of their missed planets.

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Re: KELT Results

Post by Sirius_Alpha on 13th July 2016, 9:09 pm

KELT-17b: A hot-Jupiter transiting an A-star in a misaligned orbit detected with Doppler tomography
http://arxiv.org/abs/1607.03512

We present the discovery of a hot-Jupiter transiting the V=9.23 mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a 1.31 -0.29/+0.28 Mj, 1.645 -0.055/+0.060 Rj hot-Jupiter in a 3.08 day period orbit misaligned at -115.9 +/- 4.1 deg to the rotation axis of the star. The planet is confirmed via both the detection of the radial velocity orbit, and the Doppler tomographic detection of the shadow of the planet over two transits. The nature of the spin-orbit misaligned transit geometry allows us to place a constraint on the level of differential rotation in the host star; we find that KELT-17 is consistent with both rigid-body rotation and solar differential rotation rates (alpha < 0.30 at 2 sigma significance). KELT-17 is only the fourth A-star with a confirmed transiting planet, and with a mass of 1.635 -0.061/+0.066 Msun, effective temperature of 7454 +/- 49 K, and projected rotational velocity v sin I_* = 44.2 -1.3/+1.5 km/s; it is amongst the most massive, hottest, and most rapidly rotating of known planet hosts.

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Re: KELT Results

Post by Sirius_Alpha on 2nd August 2016, 8:33 pm

KELT-16b: A highly irradiated, ultra-short period hot Jupiter nearing tidal disruption
http://arxiv.org/abs/1608.00618

We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright (V=11.7) star TYC 2688-1839-1/KELT-16. A global analysis of the system shows KELT-16 to be a F7V star with Teff=6236±54 K, logg⋆=4.253+0.031−0.036, [Fe/H]=−0.002+0.086−0.085, M⋆=1.211+0.043−0.046M⊙, and R⋆=1.360+0.064−0.053R⊙. The planet is a relatively high mass inflated gas giant with MP=2.75+0.16−0.15MJ, RP=1.415+0.084−0.067RJ, density ρP=1.20±0.18 g cm−3, surface gravity loggP=3.530+0.042−0.049, and Teq=2453+55−47 K. The best-fitting linear ephemeris is TC=2457247.24791±0.00019 BJDTBD and P=0.9689951±0.0000024 days. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with P<1 day. Its ultra-short period and high irradiation make it a benchmark target for atmospheric studies by HST, Spitzer, and eventually JWST. For example, as a hotter, higher mass analog of WASP-43b, KELT-16b may feature an atmospheric temperature-pressure inversion and day-to-night temperature swing extreme enough for TiO to rain out at the terminator. KELT-16b could also join WASP-43b in extending tests of the observed mass-metallicity relation of the Solar System gas giants to higher masses. KELT-16b currently orbits at a mere ∼ 1.7 Roche radii from its host star, and could be tidally disrupted in as little as a few ×105 years (for a stellar tidal quality factor of Q′∗=105). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov oscillations played a role in driving KELT-16b inward to its current precarious orbit.

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Re: KELT Results

Post by Sirius_Alpha on 16th August 2016, 11:53 pm

KELT-12b: A P∼5 Day, Highly Inflated Hot Jupiter Transiting a Mildly Evolved Hot Star
http://arxiv.org/abs/1608.04714

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Re: KELT Results

Post by Lazarus on 7th February 2017, 3:08 pm

McLeod et al. "KELT-18b: Puffy Planet, Hot Host, Probably Perturbed"
https://arxiv.org/abs/1702.01657
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KELT-9b: a planet as hot as a K dwarf star.

Post by Stalker on 5th June 2017, 3:37 pm

A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature22392.html
The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300–10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside2, and is highly inflated–traits that have been linked to high insolation3,4. However, even at the temperature of its dayside, its atmosphere probably resembles the  molecule-dominated atmospheres of other planets and, given  the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star6.

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Re: KELT Results

Post by Lazarus on 22nd June 2017, 3:30 am

KELT-9b paper now on arXiv: https://arxiv.org/abs/1706.06723
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Re: KELT Results

Post by Sirius_Alpha on 6th July 2017, 8:27 pm

KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603
https://arxiv.org/abs/1707.01518

We report the discovery of KELT-20b, a hot Jupiter transiting a V~7.6 early A star with an orbital period of P~3.47 days. We identified the initial transit signal in KELT-North survey data. Archival and follow-up photometry, the Gaia parallax, radial velocities, Doppler tomography, and adaptive optics imaging were used to confirm the planetary nature of the companion and characterize the system. From global modeling we infer that the host star HD 185603 is a rapidly-rotating (VsinI~120 km/s) A2V star with an effective temperature of Teff=8730K, mass of Mstar=1.76Msun, radius of Rstar=1.561Rsun, surface gravity of logg=4.292, and age of <600 Myr. The planetary companion has a radius of 1.735+0.070−0.075 RJ, a semimajor axis of a=0.0542+0.0014−0.0021AU, and a linear ephemeris of BJDTDB=2457503.120049±0.000190+E(3.4741070±0.0000019). We place a 3σ upper limit of ~3.5 MJ on the mass of the planet. The Doppler tomographic measurement indicates that the planetary orbit is well aligned with the projected spin-axis of the star (λ=3.4±2.1 degrees). The inclination of the star is constrained to be 24.4<I∗<155.6 degrees, implying a true (three-dimensional) spin-orbit alignment of 1.3<ψ<69.8 degrees. The planet receives an insolation flux of ∼8×109 erg s−1 cm−2, implying an equilibrium temperature of of ~ 2250 K, assuming zero albedo and complete heat redistribution. Due to the high stellar Teff, the planet also receives an ultraviolet (wavelengths d≤91.2~nm) insolation flux of ∼9.1×104 erg s−1 cm−2, which may lead to significant ablation of the planetary atmosphere. Together with WASP-33, Kepler-13 A, HAT-P-57, KELT-17, and KELT-9, KELT-20 is the sixth A star host of a transiting giant planet, and the third-brightest host (in V) of a transiting planet.

The planet has also been independently discovered by MASCARA,

MASCARA-2 b: A hot Jupiter transiting a mV=7.6 A-star
https://arxiv.org/abs/1707.01500

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Re: KELT Results

Post by Sirius_Alpha on 21st September 2017, 8:32 pm

KELT-19Ab: A P~4.6 Day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion
https://arxiv.org/abs/1709.07010

We present the discovery of the giant planet KELT-19Ab, which transits the moderately bright (V∼9.9) A8V star TYC 764-1494-1. We confirm the planetary nature of the companion via a combination of low-precision radial velocities, which limit the mass to MP<4.1MJ (3σ), and a clear Doppler tomography signal, which indicates a retrograde projected spin-orbit misalignment of λ=−179.7+3.7−3.8 degrees. Global modeling indicates that the Teff=7500±110K host star has M∗=1.62+0.25−0.20M⊙ and R∗=1.83±0.10R⊙. The planet has a radius of RP=1.91±0.11RJ and receives a stellar insolation flux of ∼3.2×109ergs−1cm−2, leading to an inferred equilibrium temperature of Teq∼1935K assuming zero albedo and complete heat redistribution. With a vsinI∗=84.8±2.0kms−1, the host star is rapidly-rotating. Interestingly, its vsinI∗ is relatively low compared to other stars with similar effective temperatures, and it appears to be enhanced in metallic species such as strontium but deficient in others such as calcium, suggesting that it is likely an Am star. KELT-19A would be the first definitive detection of an Am host of a transiting planet of which we are aware. Adaptive optics observations of the system reveal the existence of a companion with late G9V/early K1V spectral type at a projected separation of ≈160AU. Radial velocity measurements indicate that this companion is bound. Most Am stars are known to have stellar companions, which are often invoked to explain the relatively slow rotation of the primary. In this case, the stellar companion is unlikely to have caused the tidal braking of the primary.

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Re: KELT Results

Post by Sirius_Alpha on 11th December 2017, 9:33 pm

KELT-21b: A Hot Jupiter Transiting the Rapidly-Rotating Metal-Poor Late-A Primary of a Likely Hierarchical Triple System
https://arxiv.org/abs/1712.03241

We present the discovery of KELT-21b, a hot Jupiter transiting the V=10.5 A8V star HD 332124. The planet has an orbital period of P=3.6127647±0.0000033 days and a radius of 1.586+0.039−0.040 RJ. We set an upper limit on the planetary mass of MP<3.91 MJ at 3σ confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin-orbit misalignment of λ=−5.6+1.7∘−1.9. The star has Teff=7598+81−84 K, M∗=1.458+0.029−0.028 M⊙, R∗=1.638±0.034 R⊙, and vsinI∗=146 km s−1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal-poor and α-enhanced, with [Fe/H]=−0.405+0.032−0.033 and [α/Fe]=0.145±0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.2" and with a combined contrast of ΔKS=6.39±0.06 with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of ∼0.12 M⊙, a projected mutual separation of ∼20 AU, and a projected separation of ∼500 AU from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems.

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Re: KELT Results

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