HATnet Results

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Re: HATnet Results

Post by Sirius_Alpha on 23rd August 2010, 8:55 am

Unlikely. A massive core (with super-terrestrial density) beneath your typical H-He gaseous envelope is likely the case, I think.

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Re: HATnet Results

Post by Lazarus on 23rd August 2010, 2:17 pm

So when was the last non-transiting hot Jupiter discovery announced? Seems it has been a while...

In fact, looking at the EPE catalogue for what's been discovered in 2010, there is only ONE non-transiting hot Jupiter in the list, HD 102956b, which is unusual as being the first planet within 0.6 AU of a former A-type star.
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Re: HATnet Results

Post by Borislav on 23rd August 2010, 2:47 pm

http://exoplanet.eu/catalog-all.php?mdAff=stats#tc
http://exoplanet.eu/catalog-transit.php?mdAff=stats#tc

In addition, 2010 year perhaps the first year in which number the transit planets has more than half of all announced - 33 of 65 now.

Although the course of tomorrow's announcement will all change, but by the end of the year will be announced by a large number of planets Kepler.

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Re: HATnet Results

Post by Borislav on 23rd August 2010, 3:28 pm

And then interesting to observe the competition between projects HATnet and SuperWASP. At the beginning of the year the score was 14:20. In April 2010 - 16:34. Today - 24:42.

Probably after the start of the project HAT-South is a great chance to get ahead SuperWASP.

While certainly SuperWASP not publishes a large number of his discoveries. In reality, they have not 42 - about 28 planets.

In general, in the region transit planets observed a similar situation with the California and Geneva groups.

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Hat P17b & c!

Post by lodp on 23rd August 2010, 8:09 pm

http://arxiv.org/PS_cache/arxiv/pdf/1008/1008.3898v1.pdf

And 25b:
http://arxiv.org/PS_cache/arxiv/pdf/1008/1008.3565v1.pdf

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Re: HATnet Results

Post by Sirius_Alpha on 23rd August 2010, 8:16 pm

That explains the delay in releasing HAT-P-17. Very, very nice!

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Re: HATnet Results

Post by Edasich on 24th August 2010, 2:58 am

Sirius_Alpha wrote:That explains the delay in releasing HAT-P-17. Very, very nice!

I said it was missing. Good thing Very Happy
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Re: HATnet Results

Post by Lazarus on 24th August 2010, 2:16 pm

The HAT-P-13 system is a better case for detection of TTVs though, given the wider separation, lower mass and lower eccentricity of HAT-P-17c.

(Also have to like the start of the discussion section in the HAT-P-25 paper, it basically starts with "this is a boring planet")
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Re: HATnet Results

Post by Sirius_Alpha on 29th September 2010, 8:15 pm

The orbit of HAT-P-11 is found to be misaligned, by two groups.

The Oblique Orbit of the Super-Neptune HAT-P-11b
http://arxiv.org/abs/1009.5671

We find the orbit of the Neptune-sized exoplanet HAT-P-11b to be highly inclined relative to the equatorial plane of its host star. This conclusion is based on spectroscopic observations of two transits, which allowed the Rossiter-McLaughlin effect to be detected with an amplitude of 1.5 m/s. The sky-projected obliquity is 103_{-10}^{+26} degrees. This is the smallest exoplanet for which spin-orbit alignment has been measured. The result favors a migration scenario involving few-body interactions followed by tidal dissipation. This finding also conforms with the pattern that the systems with the weakest tidal interactions have the widest spread in obliquities. We predict that the high obliquity of HAT-P-11 will be manifest in transit light curves from the Kepler spacecraft: starspot-crossing anomalies will recur at most once per stellar rotation period, rather than once per orbital period as they would for a well-aligned system.


A Possible Tilted Orbit of the Super-Neptune HAT-P-11b
http://arxiv.org/abs/1009.5677

We report the detection of the Rossiter-McLaughlin effect for the eccentric, super-Neptune exoplanet HAT-P-11b, based on radial velocity measurements taken with HDS mounted on the Subaru 8.2m telescope, and simultaneous photometry with the FTN 2.0m telescope, both located in Hawai'i. The observed radial velocities during a planetary transit of HAT-P-11b show a persistent blue-shift, suggesting a spin-orbit misalignment in the system. The best-fit value for the projected spin-orbit misalignment angle is $\lambda= 103_{-19}^{+23}$ deg. Our result supports the notion that eccentric exoplanetary systems are likely to have significant spin-orbit misalignment (e.g., HD 80606, WASP-8, WASP-14, WASP-17, and XO-3). This fact suggests that not only hot-Jupiters but also super-Neptunes like HAT-P-11b had once experienced dynamical processes such as planet-planet scattering or the Kozai migration.

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Re: HATnet Results

Post by Sirius_Alpha on 6th October 2010, 8:11 pm

HAT-P-26b: A Low-Density Neptune-Mass Planet Transiting a K Star (emphasis mine)
http://arxiv.org/abs/1010.1008

We report the discovery of HAT-P-26b, a transiting extrasolar planet orbiting the moderately bright V=11.744 K1 dwarf star GSC 0320-01027, with a period P = 4.234516 +- 0.000015 d, transit epoch Tc = 2455304.65122 +- 0.00035 (BJD), and transit duration 0.1023 +- 0.0010 d. The host star has a mass of 0.82 +- 0.03 Msun, radius of 0.79 + 0.10 - 0.04 Rsun, effective temperature 5079 +- 88 K, and metallicity [Fe/H] = -0.04 +- 0.08. The planetary companion has a mass of 0.059 +- 0.007 MJ, and radius of 0.565 + 0.072 - 0.032 RJ yielding a mean density of 0.40 +- 0.10 g cm-3. HAT-P-26b is the fourth Neptune-mass transiting planet discovered to date. It has a mass that is comparable to those of Neptune and Uranus, and slightly smaller than those of the other transiting Super-Neptunes, but a radius that is ~65% larger than those of Neptune and Uranus, and also larger than those of the other transiting Super-Neptunes. HAT-P-26b is consistent with theoretical models of an irradiated Neptune-mass planet with a 10 Mearth heavy element core that comprises >~ 50% of its mass with the remainder contained in a significant hydrogen-helium envelope, though the exact composition is uncertain as there are significant differences between various theoretical models at the Neptune-mass regime. The equatorial declination of the star makes it easily accessible to both Northern and Southern ground-based facilities for follow-up observations.

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Re: HATnet Results

Post by Borislav on 7th October 2010, 12:37 am

Cool! HAT-net is striking for its efficiency - has two transit Neptune!

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Re: HATnet Results

Post by Lazarus on 7th October 2010, 5:01 am

So the Neptune-mass planets also have substantial variations in radii. Nice, they were starting to get predictable Smile
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Re: HATnet Results

Post by lodp on 7th October 2010, 8:27 pm

http://arxiv.org/PS_cache/arxiv/pdf/1010/1010.1318v1.pdf

Third body in HAT P4 system hinted at

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Re: HATnet Results

Post by Edasich on 8th October 2010, 4:07 am

And retrograde orbit for HAT-P-14 b too.
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Re: HATnet Results

Post by Borislav on 9th October 2010, 5:34 am

Now among all the transiting planets HAT-P-26b has 3-position at the lower mass and the 6-position of the smallest radius.

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Re: HATnet Results

Post by Borislav on 10th October 2010, 9:45 am

http://www.noao.edu/perl/abstract?2010A-0127

Abstract: Over the past years, the HATNet project has produced dozens of transiting exoplanet (TEP) candidates around bright (V<13.0) stars. In order to confirm their planetary nature, and perform accurate initial characterization, they require high-precision radial velocity (RV) observations and spectral line bisector analysis. Based on Keck/HIRES observations, \bf 13 HATNet TEPs have been announced (including HAT-P- 11b, a transiting super-Neptune around a 9th magnitude star in the Kepler field), 7 more have been verified and are being readied for publication, ~9 more need further Keck/HIRES spectra for better characterization leading to final confirmation, ~23 more are ready for initial HIRES observations. We expect an additional ~25 candidates per semester. These are high quality candidates: based on statistics to date, \bf 75% of the HIRES time is spent on candidates that are eventually identified as hosting transiting planets, meaning a very efficient use of Keck. We propose for 4 nights on Keck-I/HIRES for 2010A, and for long-term status, to finish pending candidates and also to perform a similar analysis on new targets. We are confident that \bf this effort will lead to the announcement of several new TEPs per semester.

http://www.noao.edu/perl/abstract?2010B-0130

Abstract: The HATNet project has produced dozens of transiting exoplanet (TEP) candidates around bright (V<13.0) stars. In order to confirm their planetary nature, and perform accurate initial characterization, they require high-precision radial velocity (RV) observations and spectral line bisector analysis. \bf Fifteen HATNet TEPs have been published or submitted so far based almost entirely on Keck/HIRES observations; another 10 have been verified and are in the process of being analyzed, some of these may require additional observations if detailed analysis suggests the presence of additional planets in the system or a non-zero eccentricity, ~15 more need further Keck/HIRES spectra for better characterization leading to final confirmation, and ~15 more are ready for initial HIRES observations. We expect dozens of additional candidates per semester. These are high quality candidates: based on statistics to date, \bf 75% of the HIRES time is spent on candidates that are eventually identified as hosting transiting planets- representing a very efficient use of Keck. We propose for 4 nights on Keck-I/HIRES for 2010B to finish pending candidates and also to perform a similar analysis on new targets. We are confident that \bf this effort will lead to the announcement of several new TEPs.

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Re: HATnet Results

Post by Edasich on 10th October 2010, 1:22 pm

Corot loses Razz

However first prize to SuperWASP so far. Wink
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Re: HATnet Results

Post by Borislav on 18th December 2010, 3:31 am

http://www.noao.edu/perl/abstract?2011A-0207

Twenty-six HATNet TEPs have been published or submitted so far based almost entirely on Keck/HIRES observations; several more have been verified and are in the process of being analyzed, some of these may require additional observations if detailed analysis suggests the presence of additional planets in the system or a non-zero eccentricity, ~20 more need further Keck/HIRES spectra for better characterization leading to final confirmation, and ~12 more are ready for initial HIRES observations. There is a continuous flow of dozens of high quality candidates per semester.

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Re: HATnet Results

Post by Sirius_Alpha on 18th January 2011, 9:11 pm

HAT-P-27b: A hot Jupiter transiting a G star on a 3 day orbit
http://arxiv.org/abs/1101.3511

We report the discovery of HAT-P-27b, a transiting extrasolar planet orbiting the moderately bright V=12.214 G8 dwarf star GSC 0333-00351, with period P = 3.039586 +/- 0.000012 d, transit epoch Tc = 2455186.01879 +/- 0.00054 (BJD), and transit duration 0.0705 +/- 0.0019 d. The host star has a mass of 0.94 +/- 0.04 Msun, radius 0.90 +/- 0.04 Rsun, effective temperature 5300 +/- 90 K, and metallicity [Fe/H] = +0.29 +/- 0.10. The planetary companion has a mass of 0.660 +/- 0.033 MJ and radius 1.038 +0.077 -0.058 RJ, yielding a mean density 0.73 +/- 0.13 g cm^{-3}. According to recent theoretical models, these parameters are consistent with a 4 Gyr old planet having a 10 MEarth core. A negative correlation between host star metallicity and planetary radius is found at a 0.03% level of statistical significance for known transiting exoplanets between 0.3 MJ and 0.8 MJ.

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HAT-P-6 b -- Another retrograde planet

Post by Sirius_Alpha on 26th January 2011, 9:25 pm

The retrograde orbit of the HAT-P-6b exoplanet
http://arxiv.org/abs/1101.5009

We observed with the SOPHIE spectrograph (OHP, France) the transit of the HAT-P-6b exoplanet across its host star. The resulting stellar radial velocities display the Rossiter-McLaughlin anomaly and reveal a retrograde orbit: the planetary orbital spin and the stellar rotational spin point towards approximately opposite directions. A fit to the anomaly measures a sky-projected angle lambda = 166 +/- 10 degrees between these two spin axes. All seven known retrograde planets are hot jupiters with masses M_p < 3 M_Jup. About two thirds of the planets in this mass range however are prograde and aligned (lambda ~ 0). By contrast, most of the more massive planets (M_p > 4 M_Jup) are prograde but misaligned. Different mechanisms may therefore be responsible for planetary obliquities above and below ~3.5 M_Jup.

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Re: HATnet Results

Post by Edasich on 27th January 2011, 5:17 am

To move in HATNet results, I think.
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Re: HATnet Results

Post by Edasich on 9th March 2011, 1:42 pm

Two more transiting hot Jupiters.

http://exoplanet.eu/star.php?st=HAT-P-28

http://exoplanet.eu/star.php?st=HAT-P-29
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Re: HATnet Results

Post by Sirius_Alpha on 22nd March 2011, 2:22 am

HAT-P-30b: A transiting hot Jupiter on a highly oblique orbit
http://arxiv.org/abs/1103.3825

We report the discovery of HAT-P-30b, a transiting exoplanet orbiting the V=10.419 dwarf star GSC 0208-00722. The planet has a period P=2.810595+/-0.000005 d, transit epoch Tc = 2455456.46561+/-0.00037 (BJD), and transit duration 0.0887+/-0.0015 d. The host star has a mass of 1.24+/-0.04 Msun, radius of 1.21+/-0.05 Rsun, effective temperature 6304+/-88 K, and metallicity [Fe/H] = +0.13+/-0.08. The planetary companion has a mass of 0.711+/-0.028 Mjup, and radius of 1.340+/-0.065 Rjup yielding a mean density of 0.37+/-0.05 g cm^-3. We also present radial velocity measurements that were obtained throughout a transit that exhibit the Rossiter-McLaughlin effect. By modeling this effect we measure an angle of \lambda = 73.5+/-9.0 deg between the sky projections of the planet's orbit normal and the star's spin axis. HAT-P-30b represents another example of a close-in planet on a highly tilted orbit, and conforms to the previously noted pattern that tilted orbits are more common around stars with Teff > 6250 K.

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Re: HATnet Results

Post by Sirius_Alpha on 19th May 2011, 9:11 pm

Spin-orbit inclinations of the exoplanetary systems HAT-P-8, HAT-P-9, HAT-P-16 and HAT-P-23
http://arxiv.org/abs/1105.3849

We report the measurement of the spin-orbit angle of the extra-solar planets HAT-P-8 b, HAT-P-9 b, HAT-P-16 b and HAT-P-23 b, thanks to spectroscopic observations performed at the Observatoire de Haute-Provence with the SOPHIE spectrograph on the 1.93-m telescope. Radial velocity measurements of the Rossiter-McLaughlin effect show the detection of an apparent prograde, aligned orbit for all systems. The projected spin-orbit angles are found to be lambda=-17 deg (+9.2,-11.5), -16 deg (8), -10 deg (16), +15 deg (22) for HAT-P-8, HAT-P-9, HAT-P-16 and HAT-P-23 respectively, with corresponding projected rotational velocities of 14.5 (0.8), 12.5 (1.8), 3.9 (0.8), and 7.8 (1.6) km/s. These new results increase to 37 the number of accurately measured spin-orbit angles in transiting extrasolar systems. We conclude by drawing a tentative picture of the global behaviour of orbital alignement, involving the complexity and diversity of possible mechanisms.

Edit: HAT-P-8 b's R-M effect was measured earlier (link).
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Re: HATnet Results

Post by Sirius_Alpha on 7th June 2011, 9:05 pm

HAT-P-31b,c: A Transiting, Eccentric, Hot Jupiter and a Long-Period, Massive Third-Body
http://arxiv.org/abs/1106.1169

We report the discovery of HAT-P-31b, a transiting exoplanet orbiting the V=11.660 dwarf star GSC 2099-00908. HAT-P-31b is the first HAT planet discovered without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the HATNet project. The 2.17 Mj, 1.1Rj planet has a period P = 5.0054 days and maintains an unusually high eccentricity of e = 0.2450+/-0.0045, determined through Keck, FIES and Subaru high precision radial velocities. Detailed modeling of the radial velocities indicates an additional quadratic residual trend in the data detected to very high confidence. We interpret this trend as a long-period outer companion, HAT-P-31c, of minimum mass 3.4Mj and period >2.8 years. Since current RVs span less than half an orbital period, we are unable to determine the properties of HAT-P-31c to high confidence. However, dynamical simulations of two possible configurations show that orbital stability is to be expected. Further, if HAT-P-31c has non-zero eccentricity, our simulations show that the eccentricity of HAT-P-31b is actively driven by the presence of c, making HAT-P-31 a potentially intriguing dynamical laboratory.

HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-Jitter Stars
http://arxiv.org/abs/1106.1212

We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V=11.289 star GSC 3281-00800, with a period P = 2.150008 d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high velocity jitter (~80m/s). Assuming a circular orbit, the star has a mass of 1.16+-0.04 M_sun, and radius of 1.22+-0.02 R_sun, while the planet has a mass of 0.860+-0.164 MJ, and a radius of 1.789+-0.025 RJ. When the eccentricity is allowed to vary, the best-fit model results in a planet which is close to filling its Roche Lobe. Including the constraint that the planet cannot exceed its Roche Lobe results in the following best-fit parameters: e = 0.163+-0.061, Mp = 0.94+-0.17 MJ, Rp = 2.04+-0.10 RJ, Ms = 1.18+0.04-0.07 M_sun and Rs = 1.39+-0.07 R_sun. The second planet, HAT-P-33b, orbits the bright V=11.188 star GSC 2461-00988, with a period P = 3.474474 d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter (~50m/s). In this case spectral line bisector spans are significantly anti-correlated with the radial velocity residuals, and we use this correlation to reduce the residual rms to ~35m/s. We find the star has a mass of either 1.38+-0.04 M_sun or 1.40+-0.10 M_sun, and a radius of either 1.64+-0.03 R_sun or 1.78+-0.28 R_sun, while the planet has a mass of either 0.762+-0.101 MJ or 0.763+-0.117 MJ, and a radius of either 1.686+-0.045 RJ or 1.827+-0.290 RJ, for an assumed circular orbit or for the best-fit eccentric orbit respectively. Due to the large bisector span variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date.


Last edited by Sirius_Alpha on 8th June 2011, 2:24 am; edited 1 time in total (Reason for editing : Posted the correct link to the first paper...)

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Re: HATnet Results

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