2,066 research outputs found
Combined ultraviolet studies of astronomical sources
Ultraviolet studies of astronomical sources are discussed. Some studies utilized IVE data. Non-radiative shock at the edge of the Cygnses Loop, stellar flares, local interestellar medium, hot galaxies, stellar mass ejection, contact binaries, double quasars, and stellar chromosphere and coronae are discussed
HAT-P-17b,c: A Transiting, Eccentric, Hot Saturn and a Long-period, Cold Jupiter
We report the discovery of HAT-P-17b,c, a multi-planet system with an inner
transiting planet in a short-period, eccentric orbit and an outer planet in a
4.8 yr, nearly circular orbit. The inner planet, HAT-P-17b, transits the bright
V = 10.54 early K dwarf star GSC 2717-00417, with an orbital period P =
10.338523 +/- 0.000009 d, orbital eccentricity e = 0.346 +/- 0.007, transit
epoch T_c = 2454801.16945 +/- 0.00020, and transit duration 0.1691 +/- 0.0009
d. HAT-P-17b has a mass of 0.530 +/- 0.018 M_J and radius of 1.010 +/- 0.029
R_J yielding a mean density of 0.64 +/- 0.05 g cm^-3. This planet has a
relatively low equilibrium temperature in the range 780-927 K, making it an
attractive target for follow-up spectroscopic studies. The outer planet,
HAT-P-17c, has a significantly longer orbital period P_2 = 1797^+58_-89 d and a
minimum mass m_2 sin i_2 = 1.4^+1.1_-0.4 M_J. The orbital inclination of
HAT-P-17c is unknown as transits have not been observed and may not be present.
The host star has a mass of 0.86 +/- 0.04 M_Sun, radius of 0.84 +/- 0.02,
effective temperature 5246 +/- 80 K, and metallicity [Fe/H] = 0.00 +/- 0.08.
HAT-P-17 is the second multi-planet system detected from ground-based transit
surveys.Comment: Submitted to ApJ, 13 pages, 6 figures, 6 table
HAT-P-4b: A metal-rich low-density transiting hot Jupiter
We describe the discovery of HAT-P-4b, a low-density extrasolar planet
transiting BD+36 2593, a V = 11.2 mag slightly evolved metal-rich late F star.
The planet's orbital period is 3.056536+/-0.000057 d with a mid-transit epoch
of 2,454,245.8154 +/- 0.0003 (HJD). Based on high-precision photometric and
spectroscopic data, and by using transit light curve modeling, spectrum
analysis and evolutionary models, we derive the following planet parameters:
Mp= 0.68 +/- 0.04 MJ, Rp= 1.27 +/- 0.05 RJ, rho = 0.41 +/- 0.06 g cm-3 and a =
0.0446 +/- 0.0012 AU. Because of its relatively large radius, together with its
assumed high metallicity of that of its parent star, this planet adds to the
theoretical challenges to explain inflated extrasolar planets.Comment: 5 pages, accepted for publication in ApJ
HAT-P-3b: A heavy-element rich planet transiting a K dwarf star
We report the discovery of a Jupiter-size planet transiting a relatively
bright (V = 11.56) and metal-rich early K dwarf star with a period of about 2.9
days. On the basis of follow-up photometry and spectroscopy we determine the
mass and radius of the planet, HAT-P-3b, to be M_p = 0.599 +/- 0.026 M_Jup and
R_p = 0.890 +/- 0.046 R_Jup. The relatively small size of the object for its
mass implies the presence of about 75 Earth masses worth of heavy elements (1/3
of the total mass) based on current theories of irradiated extrasolar giant
planets, similar to the mass of the core inferred for the transiting planet HD
149026b. The bulk density of HAT-P-3b is found to be rho_p = 1.06 +/- 0.17
g/cm^3, and the planet orbits the star at a distance of 0.03894 AU. Ephemerides
for the transit centers are T_c = 2,454,218.7594 +/- 0.0029 + N (2.899703 +/-
0.000054) (HJD).Comment: To appear in ApJ
Hat-P-25b: A Hot-Jupiter Transiting a Moderately Faint G Star
We report the discovery of HAT-P-25b, a transiting extrasolar planet orbiting the V = 13.19 G5 dwarf star GSC 1788-01237, with a period P = 3.652836 ± 0.000019 days, transit epoch T_c = 2455176.85173 ± 0.00047 (BJD—barycentric Julian dates throughout the paper are calculated from Coordinated Universal Time, UTC), and transit duration 0.1174 ± 0.0017 days. The host star has a mass of 1.01 ± 0.03 M_☉, radius of 0.96^(+0.05)_(– 0.04) R_☉, effective temperature 5500 ± 80 K, and metallicity [Fe/H] = +0.31 ± 0.08. The planetary companion has a mass of 0.567 ± 0.022 M_J and radius of 1.190^(+0.081)_(–0.056) R_J yielding a mean density of 0.42 ± 0.07 g cm^(–3)
Hat-P-20b-Hat-p-23b: Four Massive Transiting Extrasolar Planets
We report the discovery of four relatively massive (2-7 M J) transiting extrasolar planets. HAT-P-20b orbits the moderately bright V = 11.339 K3 dwarf star GSC 1910-00239 on a circular orbit, with a period P = 2.875317 ± 0.000004 days, transit epoch T_c = 2455080.92661 ± 0.00021 (BJD_(UTC)), and transit duration 0.0770 ± 0.0008 days. The host star has a mass of 0.76 ± 0.03 M_☉, radius of 0.69 ± 0.02 R_☉, effective temperature 4595 ± 80 K, and metallicity [Fe/H] = +0.35 ± 0.08. The planetary companion has a mass of 7.246 ± 0.187 M_J and a radius of 0.867 ± 0.033 R_J yielding a mean density of 13.78 ± 1.50 g cm^(–3). HAT-P-21b orbits the V = 11.685 G3 dwarf star GSC 3013-01229 on an eccentric (e = 0.228 ± 0.016) orbit, with a period P = 4.124481 ± 0.000007 days, transit epoch T_c = 2454996.41312 ± 0.00069, and transit duration 0.1530 ± 0.0027 days. The host star has a mass of 0.95 ± 0.04 M_☉, radius of 1.10 ± 0.08 R_☉, effective temperature 5588 ± 80 K, and metallicity [Fe/H] = +0.01 ± 0.08. The planetary companion has a mass of 4.063 ± 0.161 M_J and a radius of 1.024 ± 0.092 R_J yielding a mean density of 4.68^(+1.59)_(–0.99) g cm^(-3). HAT-P-21b is a borderline object between the pM and pL class planets, and the transits occur near apastron. HAT-P-22b orbits the bright V = 9.732 G5 dwarf star HD 233731 on a circular orbit, with a period P = 3.212220 ± 0.000009 days, transit epoch T_c = 2454930.22001 ± 0.00025, and transit duration 0.1196 ± 0.0014 days. The host star has a mass of 0.92 ± 0.03 M_☉, radius of 1.04 ± 0.04 R_☉, effective temperature 5302 ± 80 K, and metallicity [Fe/H] = +0.24 ± 0.08. The planet has a mass of 2.147 ± 0.061 M_J and a compact radius of 1.080 ± 0.058 R_J yielding a mean density of 2.11^(+0.40)_(–0.29) g cm^(–3). The host star also harbors an M-dwarf companion at a wide separation. Finally, HAT-P-23b orbits the V = 12.432 G0 dwarf star GSC 1632-01396 on a close to circular orbit, with a period P = 1.212884 ± 0.000002 days, transit epoch T_c = 2454852.26464 ± 0.00018, and transit duration 0.0908 ± 0.0007 days. The host star has a mass of 1.13 ± 0.04 M_☉, radius of 1.20 ± 0.07 R_☉, effective temperature 5905 ± 80 K, and metallicity [Fe/H] = +0.15 ± 0.04. The planetary companion has a mass of 2.090 ± 0.111 M_J and a radius of 1.368 ± 0.090 R_J yielding a mean density of 1.01 ± 0.18 g cm^(–3). HAT-P-23b is an inflated and massive hot Jupiter on a very short period orbit, and has one of the shortest characteristic infall times (7.5^(+2.9)_(–1.8) Myr) before it gets engulfed by the star
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