Do you want to publish a course? Click here

Spectroscopic Confirmation that 2MASS J07414279-0506464 is a Mid-Type L Dwarf

48   0   0.0 ( 0 )
 Added by Michael Cushing
 Publication date 2018
  fields Physics
and research's language is English




Ask ChatGPT about the research

We present a low-resolution near-infrared spectrum of 2MASS J07414279-0506464, a mid-type L dwarf candidate recently identified by Scholz & Bell. The spectrum was obtained using the Near-Infrared High Throughput Spectrograph (NIHTS) on Lowell Observatorys 4.3 m Discovery Channel Telescope and indicates that 2MASS J07414279-0506464 has a spectral type of L5.



rate research

Read More

95 - P. Bonifacio 2018
The Gaia Data Release 2 provides a parallax of 0.734+/-0.073 mas for SDSS J102915+172927, currently the most metal-poor known object. This parallax implies that it is dwarf star, ruling out the scenario that it is a subgiant. The subgiant scenario had as a corollary that the star had been formed in a medium highly enriched in C, thus making line cooling efficient during the collapse, that was also highly enriched in Fe by Type Ia SNe. This scenario can also now be ruled out for this star, reinforcing the need of dust cooling and fragmentation to explain its formation.
Photometry of Leo5 = 1H 1025+220 show that it is a dwarf nova of the Z Cam subtype. Two long standstills have been observed in the last five years.
We report the discovery of a probable L1 companion to the nearby K2 dwarf GJ 1048 using the Two Micron All-Sky Survey (2MASS). This source, 2MASSI J0235599-233120 or GJ 1048B, has 2MASS near-infrared colors and absolute magnitudes consistent with an early L dwarf companion with a projected separation of 250 A.U. The L1 spectral type is confirmed by far-red optical and low-resolution IR spectroscopy. We present evidence that GJ 1048 is a young (<~1 Gyr) system, and that GJ 1048B may be a high-mass brown dwarf below the hydrogen-burning limit. Additional studies of the GJ 1048 system will help constrain the characteristics of L dwarfs as a function of age and mass.
We present a new suite of photometric and spectroscopic data for the faint Bootes II dwarf spheroidal galaxy candidate. Our deep photometry, obtained with the INT/WFC, suggests a distance of 46 kpc and a small half-light radius of 4.0 arcmin (56 pc), consistent with previous estimates. Follow-up spectroscopy obtained with the Gemini/GMOS instrument yielded radial velocities and metallicities. While the majority of our targets covers a broad range in velocities and metallicities, we find five stars which share very similar velocities and metallicities and which are all compatible with the colors and magnitudes of the galaxys likely red giant branch. We interpret these as a spectroscopic detection of the Bootes II system. These stars have a mean velocity of -117 km/s, a velocity dispersion of (10.5+-7.4) km/s and a mean [Fe/H] of -1.79 dex, with a dispersion of 0.14 dex. At this metallicity, Boo II is not consistent with the stellar-mass-metallicity relation for the more luminous dwarf galaxies. Coupled with our distance estimate, its high negative systemic velocity rules out any physical connection with its projected neighbor, the Bootes I dwarf spheroidal, which has a velocity of ~+100 km/s. The velocity and distance of Bootes II coincide with those of the leading arm of Sagittarius, which passes through this region of the sky, so that it is possible that Bootes II may be a stellar system associated with the Sagittarius stream. Finally, we note that the properties of Bootes II are consistent with being the surviving remnant of a previously larger and more luminous dSph galaxy.
We present the spectroscopic orbits of eleven nearby, mid-to-late M dwarf binary systems in a variety of configurations: two single-lined binaries (SB1s), seven double-lined binaries (SB2s), one double-lined triple (ST2), and one triple-lined triple (ST3). Eight of these orbits are the first published for these systems, while five are newly identified multiples. We obtained multi-epoch, high-resolution spectra with the TRES instrument on the 1.5m Tillinghast Reflector at the Fred Lawrence Whipple Observatory located on Mt. Hopkins in AZ. Using the TiO molecular bands at 7065 -- 7165 Angstroms, we calculated radial velocities for these systems, from which we derived their orbits. We find LHS 1817 to have in a 7-hour period a companion that is likely a white dwarf, due to the ellipsoidal modulation we see in our MEarth-North light curve data. We find G 123-45 and LTT 11586 to host companions with minimum masses of 41 M_Jup and 44 M_Jup with orbital periods of 35 and 15 days, respectively. We find 2MA 0930+0227 to have a rapidly rotating stellar companion in a 917-day orbital period. GJ 268, GJ 1029, LP 734-34, GJ 1182, G 258-17, and LTT 7077 are SB2s with stellar companions with orbital periods of 10, 96, 34, 154, 5, and 84 days; LP 655-43 is an ST3 with one companion in an 18-day orbital period and an outer component in a longer undetermined period. In addition, we present radial velocities for both components of L 870-44AB and for the outer components of LTT 11586 and LP 655-43.
comments
Fetching comments Fetching comments
Sign in to be able to follow your search criteria
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا